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COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (applying liquids or other fluent materials to surfaces in general B05; making metal-coated products by extrusion B21C 23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D 39/00, B23K; working of metal by the action of a high concentration of electric current on a workpiece using an electrode B23H; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B 41/00 ; paints varnishes, laquers C09D; enamelling of, or applying a vitreous layer to, metals C23D; inhibiting corrosion of metallic material or incrustation in general C23F; single-crystal film growth C30B; manufacture of semiconductor devices H01L; manufacture of printed circuits H05K)
Definition statement
This subclass/group covers:

Hot-dipping or immersion processes and apparatus for applying the coating material in the molten state without affecting the shape.

Coating by spraying, casting, by vacuum evaporation, by sputtering or by ion implantation and the different aspects of chemical coating which includes

Chemical coating by decomposition of either gaseous compounds, liquid or solid compounds, solutions or suspensions of the coating forming compounds, without leaving reaction products of surface HYPERLINK "http://www.wipo.int/ipcpub/glossary?lang=en&symbol=C23C0018000000&term=material" \t "_blank" material in the coating.

Coating starting from inorganic powder.

Coating with metallic material characterized only by the composition of the metallic HYPERLINK "http://www.wipo.int/ipcpub/glossary?lang=en&symbol=C23C&term=material" \t "_blank" material.

Chemical surface treatment of metallic materials, leaving reaction products of surface material in the coating.

All coatings referred to in this subclass are either “for metallic materials” or “by metallic material,” with the exception of PVD (by vacuum evaporation, by sputtering or by ion implantation), and CVD (an aspect included in “the different aspects of chemical coating").

Solid state diffusion into metallic material surfaces.

Relationship between large subject matter areas

Applying liquids or other fluent materials to surfaces in general are classified in B05; while C23C includes the coating of metallic material and the coating material with metallic material.

Making metal-coated products by extrusion is classified in B21C 23/22 while C23C includes surface treatment of metallic material by diffusion into the surface.

Metallizing of glass is classified in C03C and Metallizing mortars, concrete, artificial stone, ceramics or natural stone is classified in C04B 41/00.

Coating with paints, varnishes, lacquers is classified in C09D.

Covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D 39/00, B23K .

Processes for the electrolytic or electrophoretic production of coatings are classified in C25D.

Processes for the electrolytic removal of materials from objects are classified in C25F.

Enameling of or applying a vitreous layer to, metals is classified in C23D .

Inhibiting corrosion of metallic material or incrustation in general is classified in C23F.

Cleaning or de-greasing of metallic material by chemical methods other than electrolysis,

e.g. cleaning, pickling are classified in C23G

References relevant to classification in this subclass
This subclass/group does not cover:
Making metal-coated products by extrusion
Metallizing of glass
Metallizing mortars, concrete, artificial stone, ceramics or natural stone
Covering with metal by connecting pre-existing layers to articles
Enameling of, or applying a vitreous layer to, metals
Treating metal surfaces or coating of metals by electrolysis or electrophoresis
Single-crystal film growth
Metallizing textiles
Decorating textiles by locally metallizing
Informative references
Attention is drawn to the following places, which may be of interest for search:
Applying liquids or other fluent materials to surfaces in general
B05
Casting for building up linings or coverings
Casting by dipping
Working of metal by the action of a high concentration of electric current on a work piece using an electrode
Inhibiting corrosion of metallic material or incrustation in general
Processes for the electrolytic removal of materials from objects
Paints, varnishes, lacquers
Details of scanning-probe apparatus, in general
Manufacture of semiconductor devices
Manufacture of printed circuits
Coating of shapes articles of macromolecular compounds
Special rules of classification within this subclass

In this subclass, an operation is considered as pretreatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation. If an operation results in the formation of a permanent sub-layer or upper layer, it is considered as pre-treatment or after-treatment only if it has a direct impact on the layer above or below respectively.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
METALLIC MATERIAL COVERS:M etals; Alloys which are metallic composite materials containing a substantial proportion of fibers or other somewhat larger particles;ceramic compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides or silicides, e.g. cermets, or other metal compounds, e.g. oxyni trides or sulfides, other than as macroscopic reinforcing agents.
Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
Definition statement
This subclass/group covers:

This main group covers:

Metallic coatings obtained by dipping or immersing a substrate into a molten bath of the coating material, where the substrate itself remains essentially unchanged, as well as any methods and/or apparatuses specifically used thereof.

References relevant to classification in this group
This subclass/group does not cover:
Enamelling of, or applying a vitreous layer to, metals
Casting molten material on the substrate
Formation of mono or polycrystalline Si coatings by pulling high temperature resistant wires and/or sheets through molten silicon.
Informative references
Attention is drawn to the following places, which may be of interest for search:
Control devices or methods specially adapted for metal-rolling mills
Layered products essentially comprising metal
Single-crystal growth by pulling from a melt, pulling on a substrate
Production of homogeneous polycrystalline material with defined structure, from liquids, by pulling from a melt
Controlling or regulating thickness in general
Special rules of classification within this group

Classes are given to well disclosed coatings and/or methods. Classes are further given to related methods, such as pre-treatment(s) of the substrate or after-treatment(s) of the coating. Classes are also further given to apparatus features important to the coating method.

In this main group, an operation is considered as pre-treatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation.

All well-disclosed, non-trivial examples of methods and/or coatings are classified.

Precedence rules indicated in the headers of the subgroups are to be strictly followed, e.g. removal by air knives of an excess of molten material on a strip is to be classified only in C23C 2/20, and not also in C23C 2/26 and C23C 2/40.

Alloys based on a given metal are alloys where said metal makes up at least 50% by weight of said alloy (see in particular C23C 2/06, C23C 2/08, C23C 2/10 and C23C 2/12).

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
Metals and metals alloys, also including inorganic materials such as oxides, carbides, nitrides, borides, silicides and their mixtures
[N: Pattern or selective deposit without pre-treatment of the material to be coated]
Definition statement
This subclass/group covers:

Pattern or selective deposition done by means externals to the substrate, e.g. masking elements such as casings, shields, fixtures or blocking elements.

Pre-treatment of the material to be coated, e.g. for coating on selected surface areas (C23C 2/30 takes precedence)
Definition statement
This subclass/group covers:

Pre-treatment of the material to be coated, for example:

  • Cleaning or etching treatments
  • Physical treatments such as roughening, grinding or polishing
  • Deposition of sublayers, i.e. adhesion layers, masking layers
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pre-treatment of metallic material, by etching with chemical means
Pre-treatment of metallic material, by cleaning/pickling/degreasing
Fluxes or coverings on molten baths
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subgroup, the following terms (or expressions) are used with the meaning indicated:

Covering
A chemical compound and/or composition, usually immiscible with the melt and having a lower density, i.e. not a physical object.
Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge (spraying guns B05B; making alloys containing fibres or filaments by thermal spraying of metal C22C 47/16 ; plasma guns H05H )
Definition statement
This subclass/group covers:

Coating processes in which melted or partially melted materials are sprayed, i.e. propelled, onto a surface, as well as apparatuses specifically used thereof.

The material to be deposited is typically fed into the spray gun in powder, wire or rod form where it is rapidly heated and melted or partially melted by electrical (plasma or arc) or chemical means (combustion flame, detonation), before being accelerated towards the substrate to be coated.

The obtained coatings are characterized by a lamellar grain structure resulting from the rapid solidification of small globules, flattened from striking a cold surface at high velocities.

Relationship between large subject matter areas

Protective layers or coatings deposited by spraying for specific articles is classified in this group and also classified in the appropriate places for said specific articles, e.g. F01D 5/288 for protective coatings for turbine blades; F28F 19/02, F28F 19/06 for protective coatings for heat exchangers; A61L 27/28 for coating materials for prostheses; B22C 3/00 for coating compositions for surfaces of moulds, cores or patterns.

References relevant to classification in this group
This subclass/group does not cover:
Spraying of powders in which no significant melting occurs before reaching the substrate
Coating by simply casting molten material on the substrate
Informative references
Attention is drawn to the following places, which may be of interest for search:
Coating materials for prostheses
Control of spray area by means of masking elements
Apparatus for spraying by means of detonations in general
Apparatus for spraying by means of flame in general
Apparatus for spraying by means of electric arc in general
Coating compositions for surfaces of moulds, cores or patterns
Making alloys containing fibres or filaments by thermal spraying of metal
Enamelling of, or applying a vitreous layer to, metals
Protective coatings for turbine blades
Protective coatings for heat exchangers
Plasma torches in general
Special rules of classification within this group

Classes are given to well disclosed coatings and/or methods. Classes are further given to related methods, such as pre-treatment(s) of the substrate or after-treatment(s) of the coating. Classes are also further given to apparatus features important to the coating method.

In this main group, an operation is considered as pre-treatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation.

All well-disclosed, non-trivial examples of methods and/or coatings are classified.

Precedence rules indicated in the headers of the subgroups are to be strictly followed.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
Metals and metals alloys, also including inorganic materials such as oxides, carbides, nitrides, borides, silicides and their mixtures
Synonyms and Keywords
APS
Air plasma spraying
HVOF
High velocity oxygen fuel
HPPS
High pressure plasma spraying
IGPS
Inert gas plasma spraying
IPS
Inductive plasma spraying
LPPS
Low pressure plasma spraying
VPS
Vacuum plasma spraying
[N: Pattern or selective deposit without pre-treatment of the material to be coated]
Definition statement
This subclass/group covers:

Masking elements such as casings, shields, fixtures or blocking elements

Stripping foreign matter from cavities by means of gas or water jets.

Pre-treatment of the material to be coated, e.g. for coating on selected surface areas
Definition statement
This subclass/group covers:

Pre-treatment of the material to be coated, for example:

  • Cleaning or etching treatments
  • Physical treatments such as roughening, grinding or polishing
  • Deposition of sublayers, i.e. adhesion layers, masking layers
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pretreatment of metallic material, by etching with chemical means
Pretreatment of metallic material, by cleaning/pickling/degreasing
Special rules of classification within this group

Only methods which are specially adapted for, but quite distinct from the main spraying coating process, and which result in sublayers having a direct impact on the main coating layer either above (e.g. adhesion) or below (e.g. masking) should be classified in this group.

Sprayed bond coats for thermal barrier coatings (TBC) are only to be classified if the TBC is also sprayed and the bond coat is well-defined and/or exhibiting unusual characteristics.

characterised by the coating material
Special rules of classification within this group

All specific and well-defined coating compositions should be classified in the relevant subgroups, C23C 4/06 to C23C 4/105.

Metallic material, [N: e.g. mixture of metallic alloys and hard particles like SiC and WC (C23C 4/085 takes precedence)]
Definition statement
This subclass/group covers:

Metals and metal alloys compositions mixed with inorganic hard particles such as oxides, borides, carbides, nitrides and/or silicides.

References relevant to classification in this group
This subclass/group does not cover:
Pure metals or metal alloys as coating material
MCrAlY type alloys where M=Ni,Co,Fe as coating material
Pure oxides, borides, carbides, nitrides, silicides or their mixtures as coating material
Pure oxide compositions as coating material
containing only metal elements
Definition statement
This subclass/group covers:

Pure metals or metal alloys compositions.

References relevant to classification in this group
This subclass/group does not cover:
MCrAlY type alloys where M=Ni,Co,Fe as coating material
[N: MCrAl or MCrAlY type alloys where M = Ni,Co,Fe]
Definition statement
This subclass/group covers:

MCrAl or MCrAlY alloys, also when further elements are present in said alloys (e.g. Si, ...)

Oxides, borides, carbides, nitrides, silicides or mixtures thereof
Definition statement
This subclass/group covers:

Compositions including mixtures of any two or more of oxides, borides, carbides, nitrides and/or silicides, or pure borides, carbides, nitrides or silicides compositions.

References relevant to classification in this group
This subclass/group does not cover:
Pure oxides compositions as coating material
Oxides
Definition statement
This subclass/group covers:

Pure oxides compositions

Synonyms and Keywords
PSZ
Partially Stabilized Zirconia
PLZT
Lead Lanthanum Zirconate Titanate
PZT
Lead Zirconate Titanate
YSZ
Yttria Stabilized Zirconia
characterised by the method of spraying
Definition statement
This subclass/group covers:

Coating by spraying the cotaing material in the molten state characterised by the method of spraying.

Special rules of classification within this group

All specific and well-defined methods and/or apparatuses should be classified in the relevant subgroups, C23C 4/121 to C23C4/10N.

[N: Spraying molten metal]
Definition statement
This subclass/group covers:

Processes and apparatuses in which the material to be deposited is melted in a furnace, then the molten material is slowly poured through a conical tundish into a small-bore ceramic nozzle. The molten material exits the furnace as a thin free-falling stream and is broken up into droplets by an annular array of gas jets, and these droplets then proceed downwards, accelerated by the gas jets to impact onto a substrate.

References relevant to classification in this group
This subclass/group does not cover:
Continuous casting of metals
Dipping in a molten bath
Casting molten material on a substrate
[N: utilising detonation (apparatus for spraying by means of detonations in general B05B 7/0006 )]
Definition statement
This subclass/group covers:

Processes and apparatuses where oxygen and fuel is fed into a barrel along with a charge of powder of the material to be deposited. A spark is used to ignite the gas mixture and the resulting detonation heats and accelerates the powder to supersonic velocity down the barrel, to deposit on the substrate.

Schematic diagram of a detonation process:

Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for spraying by means of detonations in general
[N: utilising flame spraying (apparatus for spraying by means of flame in general B05B 7/20 )]
Definition statement
This subclass/group covers:

Processes and apparatuses in which the spray material, in form of a powder or a wire, is fed continually into a fuel gas-oxygen flame where it is typically melted by the heat of combustion. A powder feed carrier gas transports the powder particles into the combustion flame, and the mixed gases transport the material towards the prepared workpiece surface.

Schematic diagram of a wire flame process:

© Sulzer Metco

Schematic diagram of a powder flame process:

© Sulzer Metco

Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for spraying by means of flame in general
[N: utilising wire arc spraying (apparatus for spraying by means of electric arc in general B05B 7/22 )]
Definition statement
This subclass/group covers:

Processes and apparatuses using two metallic wires, usually of the same composition, as the coating feedstock. The two wires are electrically charged with opposing polarity and are fed into the arc gun at matched, controlled speeds. When the wires are brought together at the contact point, the opposing charges on the wires create enough heat to continuously melt the tips of the wires. Compressed air is used to atomize the now molten material and accelerate it onto the workpiece surface to form the coating.

Schematic diagram of a wire arc process:

© Sulzer Metco

Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for spraying by means of electric arc
[N: utilising plasma spraying (plasma torches in general H05H 1/26, apparatus for spraying by means of electric arc in general B05B 7/22 )]
Definition statement
This subclass/group covers:

Processes and apparatuses where an electric arc is generated between an anode and a cathode. This ionizes the flowing process gases into the plasma state. Powdered feedstock material is injected into the plasma jet, melting the powder particles and propelling them to the surface of the workpiece.

Schematic diagram of a plasma spray process:

© Sulzer Metco

Informative references
Attention is drawn to the following places, which may be of interest for search:
Apparatus for spraying by means of electric arc in general
Plasma torches in general
[N: Spraying in vacuum or in an inert gas chamber]
Definition statement
This subclass/group covers:

Coating by spraying in vaccum or in an inert gas chamber the coating material in the molten state, for example:

Spraying at below atmospheric pressure

Spraying using inert gas shrouds or in enclosures filled with inert gas

Synonyms and Keywords
IGPS
Inert Gas Plasma Spraying
IPS
Inductive Plasma Spraying
LPPS
Low Pressure Plasma Spraying
VPS
Vacuum Plasma Spraying
Coating by casting molten material on the substrate
Definition statement
This subclass/group covers:

Processes and apparatuses involving pouring molten, i.e. liquid, material onto a substrate to form a coating.

References relevant to classification in this group
This subclass/group does not cover:
Casting molten macromolecular compounds, i.e. polymers, on a substrate
Dipping in a molten metal bath
Spraying molten metals
Enamelling of, or applying a vitreous layer to, metals
Informative references
Attention is drawn to the following places, which may be of interest for search:
Continuous casting of metals
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Material
Metals and metals alloys, also including inorganic materials such as oxides, carbides, nitrides, borides, silicides and their mixtures
Solid state diffusion of only non-metal elements into metallic material surfaces (diffusion of silicon C23C 10/00); Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals (C23C 14/00 takes precedence)
Definition statement
This subclass/group covers:

The diffusion of non-metal elements such as carbon, oxygen, nitrogen, but also boron, phosphor, sulfur, selenium or tellurium into a metal or metal alloy surface by contact with either a reactive gas (e.g. oxygen, hydrocarbons, nitrogen), a liquid (e.g. salt melts) or a solid (e.g. powders, pastes).

Coatings obtained by oxidising, carburising, nitriding, carbo-nitriding and/or boronising a metal or metal alloy surface.

References relevant to classification in this group
This subclass/group does not cover:
Diffusion of only metal elements or silicon into a metallic surface
Diffusion of at least one non-metal element other than silicon and at least one metal element or silicon into metallic material surfaces
Coating by evaporation, by sputtering or by ion implantation of the coating forming material
Reactive after treatment of PVD coatings with sulfur, selenium and/or tellurium
Electroless plating
Conversion or passivation coatings obtained by reaction of the metallic surface with a reactive liquid, e.g. chromate, phosphate and/or silicate conversion coatings
Conversion coatings obtained by electrolytic surface reaction, e.g. anodisation, phosphatising, chromatising
Process or apparatus specially adapted for the manufacture or treatment of semiconductors devices, e.g. doping of semiconductors
Informative references
Attention is drawn to the following places, which may be of interest for search:
General methods or devices for heat treatment of ferrous or non-ferrous metals or alloys
Special rules of classification within this group

Classes are given to well disclosed coatings and/or methods. Classes are further given to related methods, such as pre-treatment(s) of the substrate or after-treatment(s) of the coating.

An operation is considered as pre-treatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation.

All well-disclosed, non-trivial examples of methods and/or coating are classified.

Precedence rules indicated in the headers of the subgroups are to be strictly followed.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Ferrous surfaces
Surfaces containing a majority of iron per weight, such as but not limited to steel and cast iron
Pre-treatment of the material to be coated (C23C 8/04 takes precedence)
Definition statement
This subclass/group covers:

Cleaning or etching treatments

Physical treatments such as roughening, grinding or polishing

Deposition of sublayers, i.e. adhesion layers, masking layers

Informative references
Attention is drawn to the following places, which may be of interest for search:
Pre-treatment of metallic material, by etching with chemical means
Pre-treatment of metallic material, by cleaning/pickling/degreasing
Treatment of selected surface areas, e.g. using masks
Definition statement
This subclass/group covers:

Masking elements such as casings, shields, fixtures or blocking elements, as well as masking layers or tapes.

Treatments on selected surface areas also not involving masking elements.

using ionized gases, e.g. ionnitriding (discharge tubes with provision for introducing objects or material to be exposed to the discharge H01J 37/00 )
Definition statement
This subclass/group covers:

Solid state diffusion of only non-metal elements into metallic material surfaces by reaction of the metallic surface with ionised gases, leaving reaction products of surface material in the coating, e.g. ionnitriding.

References relevant to classification in this group
This subclass/group does not cover:
Coating by evaporation, sputtering or ion implantation
Chemical vapour deposition
Informative references
Attention is drawn to the following places, which may be of interest for search:
Discharge tubes with provision for introducing objects or material to be exposed to the discharge
Solid state diffusion of only metal elements or silicon into metallic material surfaces
Definition statement
This subclass/group covers:

This main group covers:

The diffusion of metal elements or silicon into a metal or metal alloy surface by contact with either a reactive gas, a liquid (e.g. salt or metal melts) or a solid (e.g. powders, pastes).

References relevant to classification in this group
This subclass/group does not cover:
Diffusion of non-metal elements other than silicon into a metal or metal alloy surface
Diffusion of at least one non-metal element other than silicon and at least one metal element or silicon into metallic material surfaces
Coating by evaporation, by sputtering or by ion implantation of the coating forming material
Electroless plating
Conversion or passivation coatings obtained by reaction of the metallic surface with a reactive liquid, e.g. chromate, and/or silicate conversion coatings
Conversion coatings obtained by electrolytic surface reaction, e.g. anodisation, chromatising
Process or apparatus specially adapted for the manufacture or treatment of semiconductors devices, e.g. doping of semiconductors
Informative references
Attention is drawn to the following places, which may be of interest for search:
General methods or devices for heat treatment of ferrous or non-ferrous metals or alloys
Special rules of classification within this group

Classes are given to well disclosed coatings and/or methods. Classes are further given to related methods, such as pre-treatment(s) of the substrate or after-treatment(s) of the coating.

An operation is considered as pre-treatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation.

All well-disclosed, non-trivial examples of methods and/or coatings are classified.

Precedence rules indicated in the headers of the subgroups are to be strictly followed.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Ferrous surfaces
Surfaces containing a majority of iron per weight, such as but not limited to steel and cast iron
Pretreatment of the material to be coated (C23C 10/04 takes precedence)
Definition statement
This subclass/group covers:

Pretretaments of the material to be coated, for example:

  • Cleaning or etching treatments
  • Physical treatments such as roughening, grinding or polishing
  • Deposition of sublayers, i.e. adhesion layers, masking layers
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pre-treatment of metallic material, by cleaning/pickling/degreasing
Pre-treatment of metallic material, by etching with chemical means
Diffusion into selected surface areas, e.g. using masks
Definition statement
This subclass/group covers:

Masking elements such as casings, shields, fixtures or blocking elements, as well as masking layers or tapes.

Treatments on selected surface areas also not involving masking elements.

Solid state diffusion of at least one non-metal element other than silicon and at least one metal element or silicon into metallic material surfaces
References relevant to classification in this group
This subclass/group does not cover:
Diffusion of only metal elements or silicon into a metallic surface
Coating by evaporation, by sputtering or by ion implantation of the coating forming material
Electroless plating
Conversion or passivation coatings obtained by reaction of the metallic surface with a reactive liquid, e.g. chromate, and/or silicate conversion coatings
Diffusion of only non-metal elements other than silicon into a metallic surface
Conversion coatings obtained by electrolytic surface reaction, e.g. anodisation, chromatising
Process or apparatus specially adapted for the manufacture or treatment of semiconductors devices, e.g. doping of semiconductors
Informative references
Attention is drawn to the following places, which may be of interest for search:
General methods or devices for heat treatment of ferrous or non-ferrous metals or alloys
Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material (discharge tubes with provision for introducing objects or material to be exposed to the discharge H01J 37/00 )
Definition statement
This subclass/group covers:

Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material, e.g. physical vapor deposition (PVD), reactive sputtering.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Deposition of organic layers
Cleaning
Carbon (fullerenes)
Surface treatment of glass
After-treatment of ceramics
Organometallic compounds
Multilayers
Epitaxial layers
Plasma apparatuses
Semiconductors
Special rules of classification within this group

General considerations.

CPC groups are given to well disclosed PVD (physical vapor deposition) coating methods.

CPC groups are further given to related methods, such as pre-treatment of the substrate or after-treatment of the coating.

CPC groups are further given to apparatus features important to the coating method, such as crucibles for the source material in PVD.

Trivial references to well known PVD processes are not classified. As an example "...the SiO2 layer was deposited by sputtering..." may be mentioned.

In this subclass, an operation is considered as pre-treatment or after-treatment when it is specially adapted for, but quite distinct from, the coating process concerned and constitutes an independent operation. 

If an operation results in the formation of a permanent sub-layer or upper layer, it is  considered as pre-treatment or after- treatment only if it has a direct impact on the layer above or below respectively.

During classification in C23C 14/00 it is common that a document is vague about some of the subject-matter relating to PVD, making the classifier doubt if the document should be classified or not. The classifier should in these cases be guided by his/her own best judgement and the possible importance of the well disclosed subject-matter.

Specific considerations related to specific parts of the classification scheme:

Most of the groups in C23C 14/00 are self-explanatory. Below some explanation of non obvious aspects.

C23C 14/0021-C23C 14/0031: Material in the gas phase is achieved by evaporation, laser ablation etc and reacted with another gas before or during the coating of the substrate. After-treatment with reactive gas in any form is classified in C23C 14/5846-C23C 14/5866.

C23C 14/0036-C23C 14/0084: Material in the gas phase is achieved by sputtering and reacted with another gas before or during the coating of the substrate. After-treatment with reactive gas in any form is classified in C23C 14/5846-C23C 14/5866. Note that the sequential processes in C23C 14/0073 and L2 are not considered as after-treatments.

C23C 14/024-C23C 14/027: The sub-layers are classified only if they have a direct relation to the PVD coating above. Examples are improvement of the adhesion or influence on the structure or properties of the PVD coating above.

C23C 14/04-C23C 14/048: Deliberate action to avoid coating of some areas of the substrate. Merely coating of the front side of a substrate directed towards a source of coating material and not coating the side that the substrate rests on is not classified.

C23C 14/08-C23C 14/088: The alkaline earth, refractory and iron group metals are defined in IPC section C on one of the first pages. Mixed oxides from different groups are classified in C23C 14/08. Mixed oxides from one group is classified in that group. For example Al-Mg-O is classified in C23C 14/081 but Ti-Al-O is classified in C23C 14/08.

C23C 14/10: Note that these materials are usually based on Si-O, but other types of glass should also be classified here.

C23C 14/22: Here, coating processes are classified that does not fit the groups C23C 14/221-C23C 14/48. Examples are processes based on a combinations of CVD and PVD and combinations of different PVD processes.

C23C 14/24-C23C 14/32: Some ionization usually takes place during laser ablation (C23C 14/28) and electron beam induced evaporation (C23C 14/30). However, these documents are not classified in C23C 14/32 unless further ionization of the evaporated material takes place.

C23C 14/34-C23C 14/46. In C23C 14/3407 it is particularly important to classify the method used for building up the target-backing plate unit. Remember that the features of the electrodes as such are classified in H01J 37/34.

Note further that sputtering may be performed with other particles than ions.

A sputtering process is based on the use of the kinetic energy of a particle impacting a target surface releasing target material that is subsequently deposited on a substrate.

C23C 14/56: Normal vacuum pumping is classified here. Deliberate minimization of impurities is classified in C23C 14/564.

Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition (CVD) processes (reactive sputtering or vacuum evaporation C23C 14/00 )
Definition statement
This subclass/group covers:

Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, e.g. chemical vapour deposition (CVD), chemical coating by decomposition of gaseous compounds using electric discharge (plasma coating),using non excited gas phase coating.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Deposition of organic layers
Cleaning
Carbon (fullerenes)
Surface treatment of glass
After-treatment of ceramics
Organometallic compounds
Multilayers
Epitaxial layers
Plasma apparatuses
Semiconductors
Special rules of classification within this group

General considerations.

CPC groups are given to well disclosed CVD coating methods.

CPC groups are further given to related methods, such as pre-treatment of the substrate or after-

treatment of the coating.

CPC groups are further given to apparatus features important to the coating method, such as gas inlets in CVD.

Trivial references to well known CVD processes are not classified. As an example "...the SiO2 layer was deposited by decomposition of TEOS in the presence of oxygen..." may be mentioned.

In this subclass, an operation is considered as pre-treatment or  after-treatment when it is specially adapted for, but quite distinct  from, the coating process concerned and

constitutes an independent  operation. If an operation results in the formation of a permanent sub-layer or upper layer, it is  considered as pre-treatment or after- treatment only if it has a direct impact on the layer above or below respectively.During classification in C23C 16/00 it is common that a document is vague about some of the subject-matter relating to CVD, making the classifier doubt if the document should be classified or not. The classifier should in these cases be guided by his/her own best judgement and the possible importance of the well disclosed subject-matter.

Specific considerations related to specific parts of the classification scheme.

Most of the groups in C23C 16/00 are self-explanatory. Below some explanation of non obvious aspects.

C23C 16/01: Any method for substrate coating separation is classified here, not only etching.

C23C 16/0272-C23C 16/029: The sub-layers are classified only if they have a direct relation to the CVD coating above. Examples are improvement of the adhesion or influence on the structure or properties of the CVD coating above.

C23C 16/04-C23C 16/047: Deliberately taking action to avoid coating on some areas of the substrate. Merely coating the front side of a substrate directed towards a source of coating material and not coating the side that the substrate rests on is not classified.

C23C 16/27-C23C16/27D2: All processes for deposition of diamond not in the subdivisions C23C 16/273-C23C17/27P, in particular hybrid and combination processes.

C23C 16/28: For description of the non metal elements see IPC section C one of the first pages. Here, also Ge is considered to be a non-metal as opposed to the definition in the IPC.

C23C 16/40-C23C 16/409: The alkaline earth, refractory and iron group metals are defined in IPC section C on one of the first pages. Mixed oxides from different groups are classified in C23C 16/40. Mixed oxides from one group is classified in that group. For example Al-Mg-O is classified in C23C 16/403 but Ti-Al-O is classified in C23C 16/40.

C23C 16/44: Here, coating processes are classified that does not fit the groups C23C 16/4401-C23C 16/545. Examples are processes based on a combinations of CVD and PVD and combinations of different CVD processes.

C23C 16/452: The most important aspect of this group is the CVD process where radicals but not ions from a plasma takes part in the deposition process.

C23C 16/453: These processes are only classified if a coating is made. Processes for creating "soot" for glass making are not classified here, but in C03C.

C23C 16/45525-C23C 16/45553: Sequentially exposing the substrate to the precursors: Reacting the first precursor with the surface of the substrate and subsequently reacting the first precursor on the surface of the substrate with the second precursor.

C23C 16/45563- C23C 16/4588: These groups relate largely to apparatus features that are important for the deposition process. These features are only classified if documents discloses a relation to a CVD coating method. General documents describing apparatus features are classified in the appropriate places such as H01L and B01J.

C23C 16/46 vs C23C 16/481: Note that C23C 16/481 takes precedence.

C23C 16/50-C23C 16/517: These groups relate to plasma CVD processes where in some cases apparatus features are important. These features are only classified if documents discloses a relation to a plasma CVD coating method. General document describing plasma apparatuses are classified in H01J 37/00.

Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating (chemical surface reaction C23C 8/00, C23C 22/00); Contact plating
Definition statement
This subclass/group covers:
  • Chemical coating occurring through decomposition of either liquid compounds, solutions, dispersions or paste of the coating forming compounds without leaving reactions products of surface material in the coating
  • Coating compositions, compounds or processes step specific to said coating
  • Contact plating
References relevant to classification in this group
This subclass/group does not cover:
Coating of inorganic material not in molten state, e.g. cold spray, heat or pressure on metallic substrate
Vapour coating through PVD
Vapour coating through CVD
Informative references
Attention is drawn to the following places, which may be of interest for search:
Process of fluid deposition
Molten material spraying, e.g. Plasma spraying
Diffusion onto metallic substrate
Superposed coating from at least 2 layers on metallic substrate
Electroplating
Measuring thickness
Controlling or regulating
Medical implants
Glass
Ceramics
Polymer coating composition
Ink
Capacitors
Semiconductors
Solar cells
Solution for the manufacture of photoactive layer
Printed circuit boards
Special rules of classification within this group

3 subgroups are present:

-C23C 18/02- C23C 18/14: thermal decomposition through heating or irradiation

-C23C 18/16-C23C 18/52: electroless deposition through use of a chemical reducing agent

-C23C 18/54: electroless deposition through substitution with a more electropositive metal than the one being substituted

These sub-groupss and their corresponding sub-divisions are generally self-explanatory but more details is given for the following classes:

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass, the following terms or expressions are used with the meaning indicated

Contact plating
Plating of metal surface with a more electropositive metal
by thermal decomposition
Definition statement
This subclass/group covers:

Processes, apparatus compositions or compounds for chemical coating by thermal decomposition.

Processes of chemical coating by thermal decomposition characterised by the deposition of material other than inorganic material and involving particles

Apparatus for deposition of particles in general

Process of chemical coating by thermal decomposition characterised by the deposition of metallic material including particles.

Special rules of classification within this group

Processes of chemical coating by thermal decomposition characterised by deposition of inorganic material other than metallic material, including or not particles are classified in C23C 18/12 subgroups.

Pretreatment of the material to be coated (C23C 18/06 takes precedence)
References relevant to classification in this group
This subclass/group does not cover:
Coating on selected surface areas, e.g. using masks
Coating on selected surface areas, e.g. using masks
Definition statement
This subclass/group covers:

Coating for which a pattern area is present, e.g. using masks.

Synonyms and Keywords
Keywords for coating on selected surfaces:
pattern, mask
characterised by the deposition of metallic material
Definition statement
This subclass/group covers:

Coating for the deposition of metallic material per se and coating for the deposition of aluminium per se through thermal decomposition.

characterised by the deposition of inorganic material other than metallic material
Definition statement
This subclass/group covers:

processes and product thereof whereby an inorganic material is deposited through thermal decomposition of its reactant/precursor

apparatus for said process and manufacture of product

Special rules of classification within this group

4 parts with subdivision are present within this group covering:

C23C 18/1204-C23C 18/122: the composition of the product deposited.

C23C 18/1225: the production of multilayers.

C23C 18/1229-C23C 18/1245: the composition of the substrate onto which the inorganic coating is deposited.

C23C 18/125-C23C 18/1295: the features of the process.

All 4 subdivision have equal weight: classification occurs in any or all of the 4 when features present in claims.

[N: Metal oxides (C23C 18/1212 takes precedence)]
Definition statement
This subclass/group covers:

Processes, compositions for chemical coating by thermal decomposition characterised by the deposition of metal oxides other than zeolites or glasses.

References relevant to classification in this group
This subclass/group does not cover:
Coating of Zeolites, glasses
Decomposition by irradiation, e.g. photolysis, particle radiation
Definition statement
This subclass/group covers:

Process for deposition of metallic or inorganic material through thermal decomposition by irradiation.

Special rules of classification within this group

Classification is also given to the material being deposited when known: C23C 18/08, C23C 18/12.

Synonyms and Keywords
Synomyms for decomposition by irradiation:
photochemical deposition
Keywords for decomposition by irradiation:
radiation, irradiation, e-beam, laser, UV
by reduction or substitution, e.g. electroless metal plating (C23C 18/54 takes precedence)
Definition statement
This subclass/group covers:
  • Electroless plating of metals or metal oxides
  • Constituent of electroless plating composition, i.e. special product not specific for a defined electroless metal composition
  • Dispersion of solid particle, e.g. embedded particles
  • Forming dispersion of solid particles in the product (composite) by electroless plating
  • Electroless plating using dispersion containing solid particles
References relevant to classification in this group
This subclass/group does not cover:
Contact plating
[N: Process or apparatus]
Definition statement
This subclass/group covers:

- Process or apparatus for chemical coating by reduction or substitution, for example :

-process for deposition of material through reduction or substitution by use of a chemical reducing agent

- process whereby application of reducing and metal solution are separated

Synonyms and Keywords
Synonyms for process
-chemical plating/deposition/coating -non electrolytic plating/deposition/coating-autocatalytic plating/deposition/coating
[N: coating on selected surface areas]
Definition statement
This subclass/group covers:

Electroless deposition of a patterned coating.

Special rules of classification within this group

Electroless deposition on selected surface areas by the use of mask is classified in C23C 18/1605.

Synonyms and Keywords
Synonym for coating on selected surface areas
pattern
[N: Purification and regeneration of coating baths]
Definition statement
This subclass/group covers:

Process whereby the electroless coating bath is purified or regenerated.

References relevant to classification in this group
This subclass/group does not cover:
Control of the bath/process
Pre-treatment of the material to be coated
Definition statement
This subclass/group covers:

Pretreatment not specific to a particular substrate as well as pretreatment of metallic substrate to be coated.

Special rules of classification within this group

- Pretreatment of inorganic substrate other than metallic substrate is classified in C23C 18/1851

- Pretreatment of organic substrate only is classified in C23C 18/20

- C23C 18/2006 covers pretreatment which are not covered by any sub-groups C23C 18/2013 to C23C 18/30, e.g. gas pretreatment (ozone), corona discharge, cold plasma pretreatment.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subgroup, the following terms (or expressions) are used with the meaning indicated:

Sensitising in C23C 18/28 and lower
pre-treatment to the activation step by activation of a reducing agent on the substrate surface for promoting the formation of metallic clusters on the substrate surface during the subsequent activation step, e.g. Sn based solution
Activating in C23C 18/28 and lower
Formation of catalytic site on the substrate surface by reduction of metal ions and deposition of metallic clusters, thereby facilitating subsequent electroless plating steps, e.g. Pd, Ag, Au, based solution

The steps of sensitising and activating are either used in a 2 step process or a 1 step process in the patent litterature

The term "sensitising" and "activating" are sometimes used interchangeably in the patent litterature.

Coating with metals
Definition statement
This subclass/group covers:

Metallic composition for use in electroless plating process .

Informative references
Attention is drawn to the following places, which may be of interest for search:
Electroplating composition
Special rules of classification within this group
  • Coating with a reducing agent containing phosphorus or boron does not equate to coating of alloy
  • Coating of alloy is an alloy of at least 2 metals
Contact plating, i.e. electroless electrochemical plating
Definition statement
This subclass/group covers:

Plating of metal surface (e.g. Ni, Cu) with a more electropositive metal (e.g. noble metal).

Synonyms and Keywords
Synonyms for contact plating:
displacement, immersion, cementation, exchange, dipping, replacement
Chemical coating by decomposition of either solid compounds or suspensions of the coating forming compounds, without leaving reaction products of surface material in the coating (chemical surface reaction C23C 8/00, C23C 22/00)
Special rules of classification within this group

The groups C23C 20/00-C23C 20/08 are not used, the subject matter is covered by the C23C 18/00 subgroups.

Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals (wash primers C09D 5/12)
Definition statement
This subclass/group covers:

Methods, compositions and apparatus for chemical surface treatment of metallic material by reaction of the metallic surface with a reactive liquid to form conversion or passivation coatings thereon.

This group covers also suspensions containing reactive liquids and non-reactive solid particles.

Apparatus for treating metallic material to form conversion coatings thereon (C23C 22/00).

General methods or special ones for forming conversion coatings on metallic materials that do not have an appropriate subgroup (C23C 22/00).

Conversion coatings (C23C 22/00 - C23C 22/47).

C23C 22/02 . using non-aqueous solutions

C23C 22/05 . using aqueous solutions

C23C 22/70 . using melts

Passivation, oxidation coatings (C23C 22/48 - C23C 22/58).

Conversion coatings characterized by the process (C23C 22/73).

Pretreatment of the material to be coated (C23C 22/78).

After-treatment (C23C 22/82).

Regeneration of the coating bath (C23C 22/86).

Relationship between large subject matter areas

Articles characterised by special methods of manufacture are not to be classified in this group but in the appropriate places for such articles, e.g. in F16C for shafts, bearings or parts thereof.

Protective layers or coatings for specific articles are not to be classified in this group but in the appropriate places, e.g. F01D, F28F, A61L, B22C.

References relevant to classification in this group
This subclass/group does not cover:
Protection of catalyst by coating
Apparatus for depositing polymeric coatings
Processes for applying multilayers from a liquid; Painting
B05D7/00N
Preliminary treatment of areas to be soldered
Non-corrosive coatings; primers applied before welding
Non-metallic compositions, e.g. coatings of interest in soldering or welding
Bonding rubber to metal (mechanical)
B29H9/10B
Laminates, self-supporting layers
Chemical or electrical treatment of printing surfaces with a chromium compound, a silicon compound, a phosphorous compound or a compound of a metal group IVB
Bonding rubber or polymer to a metal (chemical)
Corrosion-inhibiting coatings (anti-corrosive paints, anti-corrosion oils) for metallic material
Coating by hot-dipping or immersion in molten material
Coating by spraying molten materials, e.g. oxides
Diffusion coatings (chemical surface reaction)
PVD coatings
CVD coatings
Chemical coating by decomposition
Sol-gel coatings
Powder coatings, e.g. by spraying molten material
Other coating methods for metallic substrates
Multilayer coatings, at least two superposed coatings either by methods not provided for in a single one of groups C23C 2/00 to C23C 26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
Coating a metal defined by the composition of the coating rather than the coating process
Enamelling of, or applying a vitreous layer to, metals
Electrolytic recovery
Electrolytic coating
Informative references
Attention is drawn to the following places, which may be of interest for search:
Coating materials for prostheses
Process, in general, for preparing catalysts, e.g. by coating
Catalysts comprising oxides, or hydroxides of Mg, B, Al, C. Si, Ti, Zr, Hf
Process for applying monomolecular layers (SAM layers)
Pretreatment of surfaces to which liquids or other fluent are to be applied; After-treatment of applied coatings
Process for applying liquids or other fluent materials to obtain special surface effects, finishes or structures, e.g. for repairing damaged coatings
Processes specially adapted for applying liquids or other fluent materials to metal surfaces, e.g. car bodies, metallic pipes or tubes; or to internal surfaces of tubes or pipes
One specific pretreatment, e.g. phosphatation, chromatation, and one specific coating
B05D7/00N1
Coatings for surface of moulds, cores or pattern
Coating containing alkyl silicates or metals silicates
Coating containing alkali metals silicates
Coatings containing phosphates binders
Coatings with alkali metal silicates
Coatings with siloxanes
Reactive Wash primers, e.g. polymers (+ H3PO4, pigments, corrosion inhibitors)
Coatings based on homopolymers or copolymers having one or more unsaturated aliphatic radicals
Coatings with polyesters
Coating with polyamines
Coatings with polysilcates, polysiloxanes
Adhesive bonding involving pretreatment of the surface to be joined
Lubricating composition containing more than 10 % water and not containing mineral or fatty oils
Local protective coating
Chemical treatment of the metal surfaces prior to coating by enamelling, or by applying a vitreous layer to metals
Pretreatment of metallic material, by cleaning/pickling
Pretreatment of metallic material, by etching
Corrosion inhibitors
Electrochemical coating with inorganic materials
Electrochemical Phosphatising
Electrochemical Chromatising
Particular treatment of turbine blades
Protective coatings for turbine blades
Protective coatings for heat exchangers
Corrosion protection, e.g. by coating of magnetic steels
Applying non-metallic protective coatings
Improving adhesion between the insulating substrate and the metal by conversion of the metal surface, e.g. by oxidation
Improving adhesion between the insulating substrate and the metal by the use of a coupling agent, e.g. silane
Special rules of classification within this group

In this group it is MANDATORY to classify ALL EXAMPLES of Compositions or Methods.

Other well-disclosed and non-trivial aspects are also classified.

Rejuvenating of the bath is classified in the appropriate place for the specific bath composition.

C23C 22/24 - C23C 22/33, C23C 22/04, C23C 22/37, C23C 22/38, C23C 22/43, C23C 22/67 - treatment with acidic aqueous solutions containing hexavalent chromium compounds - an old technology being phased out due to the carcinogenic effects of hexavalent chromium compounds (see, Restriction of Hazardous Substances (RoHS) - European Union Directive 2002/95/EC).

Classification of additional information

In many cases the classification of additional information is very useful for retrieving the document, and therefore very desirable, although not compulsory. Well-known (trivial) aspects or features are not classified.

For example:

If a document discloses a "conversion process and composition for treatment of aluminium" (C23C 22/56), which in the description is also described as being suitable "for treating magnesium", and if this additional information is per se new /inventive ("non-trivial"), it is classified, namely C23C 22/57 as well.

In some cases the additional information is broadly defined as any secondary information useful for search that is not relevant per se, but that could be interesting for search when considered together with the important (invention-like) information, then it is classified with (Indexing Code), e.g. C23C 2222/10 for searching conversion coatings based on Cr(III) with no Cr(VI), C23C 2222/20 for searching conversion coatings containing or corrosion inhibiting compositions based on silanes or hydrolysis or condensation products thereof.

Subgroups and head group

In the head group C23C 22/00, the specific technical information is relevant to the apparatus for treating metallic material to form conversion coatings thereon; and the general methods or special ones for forming conversion coatings on metallic materials that do not have an appropriate subgroup.

In subgroups C23C 22/02 - C23C 22/86, in the absence of an indication to the contrary, classification is made in the last appropriate place.  

In the subgroup C23C 22/17 the specific technical information is relevant to the chemical treatment of metallic material with acidic aqueous phosphating solutions which, besides zinc ions, oxidants (nitrite, nitrate, chlorate), contains organic acids, or hydroxylamines, or nitrocompounds, such as nitrobenzene sulfonate.

In the subgroup C23C 22/73 the specific technical information is relevant to the process, e.g. two consecutive treatments or the way how the coating is applied to metallic surfaces.

In the subgroup C23C 22/74 the specific technical information is relevant to the process of conversion coatings formed by chemical reactions of concentrated reactive solutions followed by a thermal treatment (curing step) at temperatures more than 100 - 120 °C.

In the subgroup C23C 22/84 the specific technical information is relevant to the after-treatment (post-treatment) of conversion or passivation coatings by dyeing (coloration). If the conversion or passivation coating is coloured, no classification in C23C 22/84.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
covers metals and alloys (attention is drawn to the Note following the title of subclass C22C).
Phosphate coatings
Phosphate coatings are processes of chemical conversion on a metal surface to produce thin adherent phosphate compound coatings. The phosphate crystals formed on the surfaces of materials can be iron, zinc, or manganese phosphates. Among these phosphates, manganese phosphate is more suitable for wear applications. Phosphate coatings are usually applied to carbon steel, low-alloy steel, and cast iron. They can also be applied to zinc, cadmium, aluminum, and tin. Phosphate processes are hard to apply on high alloys for these alloys are likely immune to the phosphoric acid. In short, phosphating is one of the most useful non-metallic conversion coatings.
Chromate coatings
Chromate coatings, similar to phosphate coatings, are processes of chemical conversion. But the chromate coatings are formed by the reaction of water solutions of chromic acid or chromium salts. The coatings can be applied to aluminum, zinc, cadmium, and magnesium. The coatings usually have good atmospheric corrosion resistance. Chromate coatings are widely used in protecting common household products, such as screws, hinges, and many hardware items with the yellow-brown appearance.
Oxide coatings
The oxide coatings are in fact corrosion products which is a thin, usually less than 2.5 µm oxide with good adhesion. The oxide treatments are done by heat, chemicals, or electrochemical reactions.
Bluing-type oxidations
gun -bluing -type oxidations are done by heating the metals, generally steel, at 370ºC in a steam atmosphere. Chemical baths produce coatings similar to a gun bluing coating by immersion techniques.
Black oxide or blackening coatings
Black oxide or blackening coatings is a conversion coating for steel, copper, zinc, powder metals and silver solder, and most for stainless steel by treating with hot caustic soda (blackening agent). Some pastes can be rubbed on surfaces to produce similar results.
Synonyms and Keywords

In patent documents the following abbreviations are often used:

Passivation
oxidation, bluing
Conversion
phosphating or phosphatation, chromating or chromatation black oxide or blackeningcerium oxide conversion coatings
Anodizing or anodising
electrochemical conversion coating
Burned-in
cured
Condensed phosphates
polyphosphates
Dyeing
postcoloration of the conversion or passivation coating
Coating starting from inorganic powder (spraying of the coating material in molten state C23C 4/00; solid state diffusion C23C 8/00 to C23C 12/00; manufacture of composite layers, workpieces or articles by sintering metallic powder B22F 7/00; friction welding B23K 20/12 )
Definition statement
This subclass/group covers:

Coating methods where the material to be coated is applied in powder form on the surface of the substrate to be coated, e.g. cold spray methods.

Also methods where the coating material is applied in form of a slurry as long as said methods result in obtaining a coating, and not in a modification of the surface of the substrate or in a diffusion into the substrate.

References relevant to classification in this group
This subclass/group does not cover:
Manufacture of composite layers, workpieces or articles by sintering metallic powder
Friction welding
Coating mortars, concrete, artificial stone or ceramics, using a powder as coating material
Coating mortars, concrete, artificial stone or ceramics, with vitreous materials
Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
C23C 10/28 - C34C10/58
Solid state diffusion of at least one non-metal element other than silicon and at least one metal element or silicon into metallic material surfaces
Spraying of the coating material in molten state, starting from a powder
Solid state diffusion of only non-metal elements into metallic material surfaces using solids, e.g. powders, pastes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Enamelling of, or applying a non refractory vitreous layer to, metals
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
Metals or metal alloys, optionally comprising hard particles, e.g. oxides, carbides or nitrides
Impact or kinetic deposition of particles
Definition statement
This subclass/group covers:

Cold spray methods, i.e. spraying methods in which the sprayed particles are not significantly melted before reaching the substrate.

References relevant to classification in this group
This subclass/group does not cover:
Spraying of the coating material in molten state, starting from a powder
Coating not provided for in groups C23C 2/00 to C23C 24/00
Definition statement
This subclass/group covers:

Any method of coating a metallic surface and/or of coating a substrate with a metallic material which is not already described in any of groups C23C 2/00 to C23C 24/00

References relevant to classification in this group
This subclass/group does not cover:
Applying liquids or other fluent materials to surfaces in general
B05
Making metal-coated products by extrusion
Connecting objects or parts, e.g. coating with sheet metal otherwise than plating
Working of metal by the action of a high concentration of electric current on a workpiece using an electrode
Plating by soldering or welding
Metallising of glass
Metallising mortars, concrete, artificial stone, ceramics or natural stone
Paints, varnishes, lacquers
Enamelling of, or applying a vitreous layer to, metals
Treating metal surfaces or coating of metals by electrolysis or electrophoresis
Electrolytic stripping of metallic layers or coatings
Single-crystal film growth
Manufacture of semiconductor devices
Manufacture of printed circuits
applying molten material to the substrate (applying melts to surfaces, in general B05)
References relevant to classification in this group
This subclass/group does not cover:
Applying melts to surfaces, in general
B05
Dipping or immersing the substrate in a molten bath
Casting molten material on the substrate
Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C 2/00 to C23C 26/00 or by combinations of methods provided for in subclasses C23C and C25D
Definition statement
This subclass/group covers:

Multi-layered coatings, where the different layers composing the coating have been deposited by at least two different methods as disclosed in group C23C 2/00 to C23C 26/00 or by a combination of one method from C23C and one method from C25D.

Relationship between large subject matter areas

Articles characterised by special methods of manufacture are not to be classified in this group but in the appropriate places for such articles, e.g. optical coatings of optical elements G02B 1/10, magnetic record carriers G11B 5/00, resistors H01C 7/00, capacitors H01G 4/00, semiconductor and/or solid-state devices H01L, batteries and/or fuel cells H01M, semiconductor lasers H01S 5/00 and so on.

If a multilayered product classified in B32B is obtained by at least two different methods as disclosed in groups C23C 2/00 to C23C 26/00 or by a combination of methods provided for in subclasses C23C and C25, then the combination of methods should be classified in C23C 28/00 subgroups.

References relevant to classification in this group
This subclass/group does not cover:
Deposition of sublayers, e.g. to promote adhesion of the coating, prior to the deposition of a coating by PVD
Deposition of sublayers, e.g. to promote adhesion of the coating, prior to the deposition of a coating by CVD
Special rules of classification within this group
  • Classes are given to well disclosed coatings. Classes are given for all and every aspects/features present in the multi-layered coating being classified, in order to enable an easy cross-searching.
  • Multi-layered coatings where all layers are made of a metallic material, as defined in the glossary above, are classified in C23C 28/02 and subgroups.
  • Multi-layered coatings where all layers are made of an inorganic non-metallic material, as defined in the glossary above, are classified in C23C 28/04 and subgroups.
  • Multi-layered coatings comprising a mixture of metallic and non-metallic layers as defined in the glossary above, are classified in C23C28/06 and subgroups.
  • Multi-layered coatings comprising alternating layers following a pattern and/or a periodic or defined repetition are classified additionally in C23C28/08 and subgroups.
  • Coatings characterized by a main coating and an adhesion (sub)-layer are not to be classified in C23C 28/00, even if said adhesion layer is deposited using a different method as the method used for the main coating, but according to the method used for the main coating, e.g. for a PVD method in C23C 14/024, for a CVD method in C23C 16/0272.
  • Multi-layered coatings that cannot be classified in any one of the single groups C23C 28/02, C23C 28/04 or C23C28/06 and their subgroups, but still fall within the definition statement of the main group are to be classified in C23C 28/00.
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
Metals and metals alloys, not including inorganic materials such as oxides, carbides, nitrides, borides, silicides and their mixtures, with the exception where said inorganic materials are embedded in a metal matrix as hard particles, e.g. Cermets and MMC.
Inorganic non-metallic materials
Oxides, carbides, nitrides, borides, silicides and their mixtures, enamels, phosphates and sulphides.
Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C 26/00C23C 28/00 take precedence)
Definition statement
This subclass/group covers:

Coatings obtained by any of the methods of group C23C 2/00 to C23C 26/00 but characterized either by the peculiarity of their compositions or of their structures, e.g. columnar thermal barrier coatings, metal matrix composite coatings, two/multi-phase metallic coatings, quasicrystalline coatings, etc.

[N: on hard metal substrates]
Definition statement
This subclass/group covers:

Essentially coated cutting tools where the coating has been obtained by any of the methods of group C23C 2/00 to C23C 26/00 .

Relationship between large subject matter areas

Cutting tools of which the bits, tips or cutting inserts are of a special material are per se classified in B23B 27/14 and not systematically cross-classified in C23C 30/005 when said special material includes a coating.

Cutting tools coated with multi-layered coatings should also be classified in C23C 28/00, when said multi-layered coatings are of a particular interest.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Hard metal substrates
Includes cemented carbide substrates
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Last Modified: 10/11/2013