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NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K 26/00; desurfacing by applying flames B23K 7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C 1/22 ; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25.
Definition statement
This subclass/group covers:

Methods, compositions and apparatus for etching of metallic materials by chemical means (C23F 1/00 - C23F 1/44).

Regeneration of etching compositions, including apparatus for regenerating etching agents (C23F 1/46).

Methods, compositions and apparatus for chemical polishing (brightening) of metals (C23F 3/00 - C23F 3/06).

Other non-mechanical processes for removing metallic material from surfaces, e.g. by plasma or sputter etching, and compositions therefor (C23F 4/00 - C23F 4/04).

Simultaneous chemical and mechanical removal of metallic material from surfaces, e.g. by laser ablation (C23F 4/02, C23F 4/04).

Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion (C23F 11/00 - C23F 11/188).

Inhibiting corrosion of metallic material by adding inhibitors to the corrosive agent (C23F 11/00 - C23F 11/188).

Inhibiting corrosion of metals by anodic or cathodic protection (C23F 13/00 - C23F 13/22).

Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes (C23F 14/00), in polymerisation reactors (C23F 15/005).

Corrosion inhibitors per se (C23F 11/12 - C23F 11/18).

Incrustation inhibitors per se (C23F 14/02).

Other methods of preventing corrosion or incrustation, e.g. by removing the corrosive agent from the medium or rendering it non corrosive by neutralizing it (C23F 15/00).

Other apparatus for executing the methods mentioned above as far as they are specially adapted for treating metallic material, e.g. apparatus for regenerating etching agents; apparatus for anodic or cathodic protection, apparatus for executing the processes of the other groups, but only if they have at least one feature which is specifically designed for treating metallic material (C23F 1/00, C23F 3/00; C23F 4/00, C23F 13/00, C23F 14/00, C23F 15/00).

Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 (C23F 17/00).

Relationship between large subject matter areas

Protective layers or coating compositions or methods of applying them are not classified in this subclass but in the appropriate places, e.g. B05, B44, C09D, C10M, C23C.

Mechanical devices or constructional features of particular articles for inhibiting incrustation are not classified in this subclass but in the appropriate places, e.g. F16L pipes or pipe fittings.

Articles characterised by being made of materials selected for their properties of resistance to corrosion or incrustation are not to be classified in this subclass but in the appropriate places for such articles, e.g. F01D turbine blades.

Processes using enzymes or micro-organisms in order to:

liberate, separate or purify a pre-existing compound or composition, or to

treat textiles or clean solid surfaces of materials

are further classified in subclass C12S.

References relevant to classification in this subclass
This subclass/group does not cover:
Methods for preventing fouling
Working of metal by electro-erosion
De-surfacing by applying flames
Working metal by laser beam
Adding scale preventives or removers to water
Polishing compositions
Adding corrosion inhibitors to pickling solutions
Electrolytic etching or polishing
Etching process and compositions for silicon or germanium
Preventing formation of scale in cooking vessels
Producing decorative effects by removing surface material, e.g. by engraving, by etching
Mechanical methods for preventing fouling in hull protection
Application corrosion inhibitors to containers, packaging elements, or packages, for contents presenting particular transport or storage problem
Manufacture or treatment of micro-structural devices or systems in or on a substrate, e.g. MEMS devices, self-assembly devices, e.g. by etching
Preventing incrustations during destructive distillation of carbonaceous materials
Inhibition or prevention of corrosion or incrustation during processing of hydrocarbons
Use of additives to fuels or fires for minimising corrosion or incrustation
Adding corrosion inhibitors to lubricants
C10M
C10N30/12
Manufacture of two-terminal components for integrated circuits, e.g. resistors, electrodes, capacitors, inductors by etching conductive layers
H01L21/02B
Measures against corrosion for turbine blades
Preventing incrustation in pipes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Repairing fractures or cracked metal parts or products
Manufacture of printing surfaces
Surface treatment of glass by etching
Etching of natural or artificial stone or ceramics
Compositions for in situ inhibition of corrosion in boreholes or wells
Etching, surface-brightening or pickling compositions in general, e.g. for silicon, metal nitrides, etc.
Regeneration of process liquids, e.g. of etching compositions
Compositions for preventing, limiting or eliminating depositions
Portable water systems, e.g. treating plumbing systems for preventing leaching /elution of lead in water
Water supplying lines
In situ inhibition of corrosion in boreholes or wells
Preparing samples for investigations, e.g. by etching or polishing
Photomechanical reproduction
Investigating or analysing metals by specific methods, e.g. metallographic etching
Discharge tubes with the provision for introducing objects or materials to be exposed to the discharge, e.g. plasma apparatus and treatment in general (see C23F 4/00, classification rules)
Apparatus for treating semiconductor bodies
After treatment of semiconductor bodies, e.g. by physical or chemical etching of conductive layers
After treatment of semiconductor bodies, e.g. by chemical mechanical polishing of conductive layers
Chemical or electrical treatment, e.g. by etching, of semiconductor bodies
Manufacture of printed circuits
Special rules of classification within this subclass

C23F does not include methods, compositions and apparatus for treatment of non metallic material.

Groups C23F 1/00 to C23F 4/04 are not used for classifying methods, compositions and apparatuses for etching in general.

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-disclosed and non-trivial aspects are classified.

Well-known (trivial) aspects or features are not classified.

For example:

If a document discloses an "etching process and composition for aluminium" (C23F 1/20), which in the description is also described as being suitable "for etching magnesium", and if this additional information is per se new /inventive ("non-trivial"), it is classified, namely C23F 1/22 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, it is classified with (Indexing Code), e.g. "type of materials to be protected by cathodic protection (C23F 2201/00).

Subgroups and head groups

Apparatus or processes are classified in the subgroups for apparatus /process, if such subgroups exist, if not the process /apparatus are classified in the head group.

Etching /inhibiting compositions for are classified in the specific subgroups according to the intrinsic nature /function of the mixture or composition, e.g. acidic aqueous etching composition (C23F 1/16) or alkaline aqueous etching compositions (C23F 1/32).

An "application-oriented" invention should be classified in an application-oriented place (when it exists). An "application-oriented" invention is considered as:

- a thing "specially adapted for" a particular use or purpose, e.g. an apparatus modified or particularly constructed for etching /inhibiting corrosion or incrustation/ of metallic material;

- a particular use or application of a thing; e.g. alkaline composition for etching copper or alloys thereof (C23F 1/34).

If a document concerns embodiments which are covered by several subgroups (e.g. C23F 1/16 - C23F 1/30) dependent on a higher hierarchy group (head group, e.g. C23F 1/16), the following rules apply:

the specific technical information relevant for some of the subgroups is classified (EC) in all said subgroups;

if relevant, the combination of the elements covered by the subgroups is classified (EC) in the head group;

analogously, if generic technical information common to all of the subgroups is disclosed and only schematic embodiments of the specific subgroup embodiments are represented, the document is classified (EC) in the head group.

For example:

If a document discloses an acidic etching composition suitable for etching a metallic material in general, or selected from a big list of metals, without specific embodiments for the selected metals, then it is classified in the head group C23F 1/16;

If a document discloses an acidic etching composition for etching copper or alloys thereof, then it is classified in C23F 1/18;

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Metallic material
covers metals and alloys
Alloys
include: metallic composite materials containing a substantial proportion of fibres or other somewhat larger particles;ceramic compositions bonded by free metal, containing free metal bonded to carbides, diamond, oxides, borides, nitrides or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides, other than as macroscopic reinforcing agents.
Applying corrosion inhibitors
Applying corrosion inhibitors to a metallic surface layer is not considered to be applying a protective coating.
Inhibiting corrosion
Inhibiting corrosion is a specific form of preventing corrosion, the words are not synonyms
Corrosion
Deterioration of a metallic material due to a change of valence state caused by reactions with its environment.
Incrustation
Accumulation of deposition /precipitation of undesired solid /dense products on a metallic surface in systems in which a fluid circulation takes place, preferably a water-based fluid, e.g. deposition /precipitation of compounds of calcium, magnesium, barium or strontium (carbonates/ sulphates, oxalates, phosphates, fluorides, silica, silicates, naphtelenates), iron /lead / zinc sulphide, zinc /cadmium carbonates (white rust).
Synonyms and Keywords

In patent documents the expression "encrustation" is often used with the meaning " incrustation".

In patent documents the expression "fouling" is often used with the meaning " incrustation" or "rusting".

In patent documents the expression "chemical polishing" is often used with the meaning "brightening".

In patent documents the following words "incrustation", "crust" , "chalk", "limescale" and "carbonate /sulfate scale", "white rust" are often used as synonyms.

In patent documents the following words "etching", "stripping", "engraving" are often used as synonyms.

Etching metallic material by chemical means (manufacture of printing surfaces B41C; manufacture of printed circuits H05K)
Definition statement
This subclass/group covers:

Methods, compositions and apparatus for etching of metallic materials by chemical means.

Regeneration of etching compositions, including apparatus for regenerating etching agents (C23F 1/46).

Selective etching /dealloying of an element /phase from an alloy in order to obtain a porous surface (C23F 1/00).

Selective etching of complex structures (i.e. metallic mutilayers) (C23F 1/44).

Local etching e.g. by using a photoresist mask (C23F 1/02).

Apparatus for photo-mechanical printing surface (C23F 1/08).

Emulsions compositions for etching of metallic material (C23F 1/42).

In the subgroup C23F 1/10, the expression "etching composition" is used with the meaning: "etching composition for specific metals" and covers: etching composition of specific metals, and not etching composition in general;

The subgroup C23F 1/06 relates to "sharpening files" (old technology)

Relationship between large subject matter areas

Dry etching of semi-conductors are classified in H01L 21/00.

Processes of etching silicon used in semiconductors applications is classified in H01L 21/00.

Processes and compositions for etching silicon which are not for semiconductor applications are classified in C09K 13/00

References relevant to classification in this group
This subclass/group does not cover:
Etching compositions of silicon or germanium
Electrolytic etching
Etching semiconductors
Producing decorative effects by removing surface material, e.g. by engraving, by etching
Informative references
Attention is drawn to the following places, which may be of interest for search:
Manufacture of printing surfaces
Surface treatment of glass by etching
Etching of natural or artificial stone or ceramics
Recovering of metals from etching solutions
Regeneration of process liquids, e.g. of etching compositions
Cleaning of turbomachines
Repairing methods or devices for turbomachines
Photomechanical reproduction
Chemical etching of semiconductor bodies
Chemical etching of semiconductor bodies by using masks
After-treatment of conductive layers, e.g. by chemical liquid etching (wet-etching)
Semiconductor treating apparatus, e.g. for wet etching
Manufacture of printed circuits
Chemically removing of conductive material
Etching compositions
Improving adhesion between the insulating substrate and the metal by microetching
Special rules of classification within this group

The C23F1/24 IPC group is not used in the internal ECLA classification scheme. Subject-matter covered by this group is classified in the following groups: C09K 13/00 to C09K 13/08.

See the rules for classification of invention /additional information, and examples mentioned for the subclass C23F.

A selective etching composition of complex structures is classified in C23F 1/44 and the specific technical information relevant for some of the subgroups (C23F 1/14 - C23F 1/40) is classified in all said subgroups

For example:

If a document discloses an acidic etching composition for selectively etching a metal, such as Ta, from an aluminium substrate, then it is classified in the subgroups C23F 1/44 and C23F 1/26.

Processes of dry etching of metal materials by plasma, are classified in C23F 4/00.

Processes of dry etching of metal materials by using gases are classified in C23F 1/12

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Chemical Etching
Removal or dissolution of metallic material from a surface by chemical reaction between the metallic material and the etching agent
Chemical Milling
Removal of high amount of metallic material from a piece having big dimensions by chemical reaction between the metallic material and the etching agent
Synonyms and Keywords

In patent document the following abbreviations are often used:

Etching
stripping, roughening, engraving, dulling, matting, wet-etching , dry-etching
Dispersed water-immiscible liquid
powder less etching (old definition), emulsion, thixotropic etching
Brightening metals by chemical means
Definition statement
This subclass/group covers:

Methods, compositions and apparatus for chemical polishing or chemical-mechanical (brightening) of metals.

Relationship between large subject matter areas

Polishing (brightening) compositions receive an additional classification symbol in C09G (Polishing compositions other than French polish; ski waxes).

Apparatus receives an additional or only a classification symbol in B24B (Machines, devices, or processes for grinding or polishing).

Other apparatus for executing the methods mentioned above receives an additional classification symbol in C23F as far as they are specially adapted for treating metallic material (see definition field of C23F).

References relevant to classification in this group
This subclass/group does not cover:
Abrasive or related blasting, e.g. shot blasting
Electrolytic polishing
Informative references
Attention is drawn to the following places, which may be of interest for search:
Mechanical polishing apparatus, e.g. polishing pads
Polishing compositions
Abrasives, e.g. powders, suspensions, pastes for polishing
Surface-brightening compositions in general
After treatment of conductive layers, e.g. planarisation by chemical mechanical polishing
Polishing of the conductive pattern
Polishing for inhibiting the corrosion of the circuit, e.g. for preserving the solderability
Special rules of classification within this group

See the rules for classification of invention /additional information, and examples mentioned for the subclass C23F.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Chemical Polishing
Removal of metallic material from a surface in order to make the surface more bright by chemical reaction between the metallic material and the polishing agent
Chemical-Mechanical Polishing (CMP)
Removal of metallic material from a surface by combining abrasive polishing and chemical polishing, typically by applying a polishing composition or slurry to a polishing pad, establishing pressure-contact between the composition-or slurry-coated surface and the polishing pad while providing relative motion, typically rotational or orbital motion, between the surface and the polishing pad. The chemically- mechanically polishing compositions typically contains an abrasive material, such as silica, ceria, and/or alumina particles, in an acidic, neutral, or basic solution.
Synonyms and Keywords

In patent document the following abbreviations are often used:

Chemical polishing
brightening
Chemical-mechanical polishing (CMP)
planarization, smoothing, chemical-mechanical grinding, deburring
Polishing compositions
polishing slurries
Polishing
surface improvement
Grinding
improvement of the dimensional accuracy
Processes for removing metallic material from surfaces, not provided for in group C23F 1/00 or C23F 3/00
Definition statement
This subclass/group covers:

Other non-mechanical processes for removing metallic material from surfaces, e.g. by plasma or sputter etching, and compositions therefor (C23F 4/00).

Removal of metallic material from surfaces, e.g. by evaporation /volatilisation /vaporisation (EP049312, GB998708, GB817017), e.g. CO2 or YAG lasers are utilized to thermally vaporize the metal layer, excimer laser for laser ablation, or in metal-halogen systems by laser stimulated halogen gas etching of metal substrates (US4622095, US5874011), or by using an UV light to produce a product which is either volatile or easily removed in solution (US4490211, US5318662) (C23F 4/02).

Removal of metallic material from surfaces, e.g. by physical dissolution /melting (EP0158536), by laser surface melting (EP1640109)(C23F 4/04).

References relevant to classification in this group
This subclass/group does not cover:
Cleaning by radiant energy, e.g. by UV, laser, light beam
Cutting, scarfing or de-surfacing by applying flames, e.g. laser flame cutting
Working metal by laser beam, e.g. welding, cutting or boring metal parts by using plasma arc cutting torch, or a laser beam cutting head
Physical treatment to alter the texture of the surface, e.g. by irradiation with laser or particle beam
Etching semiconductors, e.g. by plasma
Informative references
Attention is drawn to the following places, which may be of interest for search:
Discharge tubes with the provision for introducing objects or materials to be exposed to the discharge, e.g. gas filled discharge tubes (plasma apparatus)
After treatment of conductive layers, e.g. by plasma etching
Apparatus or processes for manufacturing printed circuits, e.g. by the conductive material being removed by irradiation,
Special rules of classification within this group

The majority of documents to be classified in C23F 4/00 relate to removal of metallic material by plasma, which process is more physical than chemical.

Apparatus per se for dry etching are classified in H01J 37/00 and subgroups. If the apparatus has one feature specifically designed for treating metallic material, then the apparatus is also classified in C23F 4/00, e.g. plasma etching method and plasma etching apparatus for processing a magnetic film composed of iron or nickel.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Laser- induced chemical etching
Removal or dissolution of very thin layers of metallic material from a surface (in a very small amount) by reaction between the metallic material and reactive species (in the presence of reactive gases or under clean conditions) enhanced by incidence of a laser beam, e.g. by reaction of chlorine gas with aluminium is formed aluminium chloride which desorbs resulting in an etching of aluminium surface, the etching process of aluminium is further enhanced by UV laser pulses incident to the surface.
Laser -induced ablation
Removal or dissolution of very thin layers of metallic material from a surface (in a very small amount) by evaporation or physical dissolution /dissociation under clean conditions by using an UV pulsed laser, e.g. an UV Excimer -Laser.
Laser-transmissive ablation
A very thin metal film is selectively removed by means of a single radiation pulse.
Synonyms and Keywords

In patent document the following abbreviations are often used:

Plasma
discharge, DC, AC, RF, HF, UHF, MW, Hz, MHz, GHz, reactive ion etching, dry etching
Laser
light (UV, IR)
Evaporation
volatilisation, vaporization
Laser -induced chemical etching
photoetching with laser as light source
Laser -induced ablation
photoablation
Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent (adding inhibitors to mineral oil, fuels, or lubricants C10; adding inhibitors to pickling solutions C23G)
Definition statement
This subclass/group covers:

Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion.

Inhibiting corrosion of metallic material by adding inhibitors to the corrosive agent.

Preventing leaching /elution of a metallic element /phase from an alloy, e.g. in water systems (C23F 11/00).

Preventing leaching /elution of a metallic element /phase from an alloy, e.g. in water systems (C23F 11/08, C23F 11/10).

References relevant to classification in this group
This subclass/group does not cover:
Adding corrosion inhibitors to pickling solutions

Examples of places where the subject matter of this group is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Application corrosion inhibitors to containers, packaging elements, or packages, for contents presenting particular transport or storage problem
Inhibiting or prevention of corrosion during processing of hydrocarbons
Use of additives to fuels or fires for minimising corrosion
Adding corrosion inhibitors to lubricants
C10M
C10N30/12
Adding corrosion inhibitors to deicing compositions
Adding corrosion inhibitors to antifreeze compositions
Flameproofing agents (also used as corrosion inhibitors)
Adding corrosion inhibitors to water systems, e.g. treating plumbing systems for preventing leaching/elution of metals in water
Informative references
Attention is drawn to the following places, which may be of interest for search:
Application corrosion inhibitors to containers, packaging elements, or packages, for contents presenting particular transport or storage problem
Adding corrosion inhibitors to deicing compositions
Adding corrosion inhibitors to antifreeze compositions
Compositions for in situ inhibition of corrosion in boreholes or wells
Compositions for treating boreholes or wells combined with additives added for specific purposes
Anti-oxidant compositions; Compositions inhibiting the chemical change
Flame-proofing agents (also used as corrosion inhibitors in alkaline solutions)
Inhibiting or prevention of corrosion during processing of hydrocarbons
Use of additives to fuels or fires for minimising corrosion
Adding corrosion inhibitors to lubricants
C10M
C10N30/12
Adding corrosion inhibitors to pickling solutions
In situ inhibition of corrosion in boreholes or wells
Investigating resistance of metals to corrosion
Special rules of classification within this group

In the range C23F 11/12 - C23F 11/18, in the absence of an indication to the contrary, a compound is classified in the last appropriate place (last place rule).

In the head group C23F 11/00, the specific technical information is relevant to the method (process) of inhibiting corrosion, e.g. the way to apply the corrosion inhibitor, and not to the corrosion inhibitor composition.

In the subgroup C23F 11/02 the specific technical information is relevant to the method of adding volatile or vapour phase corrosion inhibitors (VpCI) to a enclosure, packaging (B65D 81/26), etc., for inhibiting the corrosion of a metallic material in air or a gases; VpCI corrosion inhibiting compositions per se.

In the subgroup C23F 11/04 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in strong acidic solutions (pH ≤1), e.g. those used in acidic treatment of boreholes or wells (C09K 8/54).

In the subgroup C23F 11/06 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in strong alkaline solutions (pH ≥14), e.g. those used in carbon dioxide capture systems.

In the subgroup C23F 11/08 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in acidic or alkaline solutions comprising mixture of organic and inorganic inhibitors, e.g. in water systems, cooling systems, etc.

The salts of amines classified in C23F 11/143 (acid /alkaline) are also classified in C23F 11/08 or C23F 11/10.

In the subgroup C23F 11/10 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in acidic or alkaline solutions comprising mixture of organic inhibitors, e.g. e.g. in water systems, cooling systems, etc.

In the subgroup C23F 11/18 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in acidic or alkaline solutions comprising inorganic inhibitors.

In the subgroup C23F 11/187 the specific technical information is relevant to the method of inhibiting corrosion of metallic material in acidic or alkaline solutions comprising mixture of inorganic inhibitors.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Applying corrosion inhibitors
Applying corrosion inhibitors to a metallic surface layer is not considered to be applying a protective coating.
Adding corrosion inhibitors
Adding corrosion inhibitors to a corrosive agent (composition) is always in a small amount, which makes a big difference between a corrosion inhibiting composition and a protective coating composition
Synonyms and Keywords

In patent document the following abbreviations are often used:

Iron corrosion inhibitor
deruster
Corrosion inhibitor
metal ions complexer/chelator/sequestrant
Inhibiting corrosion of metals by anodic or cathodic protection
Definition statement
This subclass/group covers:

Methods, apparatuses and electrode materials for inhibiting corrosion of metals by anodic or cathodic protection, i.e. for applying a current and polarizing a metallic object /structure to be protected while the object /structure is in use.

Relationship between large subject matter areas

A system of particles in a paint layer classified in C09D 5/00 receives an additional classification symbol in C23F 13/06 as far as the combination of particles and paint constitute an assembly for cathodic protection (i.e. is acting as anode for cathodic protection of a metal).

Controlling /regulating process and device for electrochemical measuring of corrosion or corrosion - protection measurement classified in G01N 17/02 receives an additional classification symbol in C23F 13/04 as far as they contain a parameter of the cathodic protection process.

References relevant to classification in this group
This subclass/group does not cover:
Anodisation
Reinforcing elements, e.g. for concrete : Anti-corrosion
Coatings or treating compositions

Examples of places where the subject matter of this group is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Electrochemical re-alcalisation, e.g. when the same device is used to apply cathodic protection and re-alcalisation, either sequently or simultaneously
Electrochemical desalination, e.g. when the same device is used to apply cathodic protection and desalination, either sequently or simultaneously
Means for protecting offshore constructions against corrosion, e.g. by cathodic protection
Arrangements for filling cracks or cavities in building constructions, e.g. cathodic protection assemblies used as well for such arrangements
Corrosion preventing means for features common to bolt and nuts, e.g. cathodic protection assemblies
Electrochemical measuring systems for weathering, corrosion or corrosion protection measurements, e.g. cathodic protection measurements
Cathodic protection of reinforced concrete structure
Cathodic protection for water heaters
Informative references
Attention is drawn to the following places, which may be of interest for search:
Component parts, detail or accessories for large containers
Compositions of mortars, concrete, artificial stone, containing inorganic binders
Anti-corrosive paints
Anti-corrosive paints containing metal dust
Anti-corrosive paints containing Al dust
Anti-corrosive paints containing Zn dust
Electrically conductive paints
Arrangements or adaptation of tanks for water supply
Reinforced concrete
Component parts of turbines for preventing corrosion
Intrinsically conductive polymers
Investigating or analysing concrete or cement by specific methods
Special rules of classification within this group

An ionic conductor as such (e.g. composition) is classified in C23F 13/02 since the ionic conductor constitutes a selection of ionic conductivity condition.

The integration of an ionic conductor in a cathodic protection system is classified in C23F 13/06 since the specific technical information relevant is the combination of the ionic conductor with other elements of the cathodic protection device.

In both cases, the KW cp ionic (C23F) has to be given to the document.

A system of particles in a paint layer (C09D 5/00) acting as anode for cathodic protection of a metal is classified in C23F 13/06 since the combination of particles and paint constitute an assembly for cathodic protection.

An electrode made of a layer directly deposited on the metal to be protected is classified in C23F 13/08.

Monitoring arrangements for electrodes, e.g. wear indicators, alarms, are classified in C23F 13/22.

C23F 2201/00 covers cathodic protection assemblies and processes in which specific material is protected by cathodic protection, i.e. when the assembly or process is specifically designed to protect a given material.

C23F 2201/02 covers any aspects of cathodic protection assemblies and processes which are specially adapted to protect reinforcement in concrete.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Anodic protection (AP)
Technique to control the corrosion of a metal surface by making it the anode of an electrochemical cell and controlling the electrode potential in a zone where the metal is passive.
Cathodic protection (CP)
Technique to control the corrosion of a metal surface by making it the cathode of an electrochemical cell
Sacrificial anode
A piece of corrodible metal, attached to a metallic surface to be protected, that is preferentially consumed by electrolytic action.
Stray currents
Stray currents may originate from direct-current distribution lines, substations, or street railway systems, etc., and flow into a pipe system or other steel structure.
Synonyms and Keywords

In patent documents the following expressions "sacrificial anode", "galvanic anode" and "active anode" are often used as synonyms.

In patent document the following abbreviations are often used:

Ionic conductor
backfill, grout, hydratant, humectant, electrochemical activating agent
Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes (adding scale preventives or removers to water C02F 5/00) [N: inhibiting incrustation in polymerisation reactors C23F 15/005]
Definition statement
This subclass/group covers:

Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes, e.g. evaporators, distillations units, crystallisation units, etc. (C23F 14/00).

Inhibiting incrustation by chemical means and incrustation inhibitors per se (C23F 14/02).

Other apparatus for executing the methods mentioned above as far as they are specially adapted for treating metallic material (C23F 14/00).

References relevant to classification in this group
This subclass/group does not cover:
Methods for preventing fouling
Adding scale preventives or removers to water

Examples of places where the subject matter of this group is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Preventing formation of scale in cooking vessels
Treatment of water, waste water or sewage
Preventing incrustations during destructive distillation of carbonaceous materials
Inhibiting or prevention of corrosion or incrustation during processing of hydrocarbons
Preventing incrustation in pipes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating
Distillation
Crystallisation
Treatment of water, waste water or sewage
Anodic or cathodic protection
Composition for preventing, limiting or eliminating depositions
Composition for preventing, limiting or eliminating inorganic depositions, e.g. sulfates or carbonates
Preventing the formation of deposits or corrosion, e.g. by using filters
Special rules of classification within this group

In the head group C23F 14/00, the specific technical information is relevant to the method (process) of inhibiting incrustations in apparatuses for heating liquids for physical or chemical purposes

In the subgroup C23F 14/02 the specific technical information is relevant to the method for preventing or removing scale formation in systems in which a fluid circulation, preferably a water-based fluid circulation takes place, by adding chemical incrustation inhibitors to the system; Incrustation inhibiting compositions per se.

The expression "inhibiting incrustation in general" is used with the meaning:

"inhibiting incrustation of metallic material " and covers: a particular purpose (application), that of inhibiting incrustation of metallic material, and not inhibiting incrustation general;

and this for two reasons:

first of all incrustation "process for forming a tenacious crust" is mainly a property of the environment where an object is placed and hardly a property of the material from which the object is made; inhibiting incrustation in general should thus be better classified in the process where the problem occurs (e.g. C02F).

secondly to make the difference with fouling "accumulation of particulates of microorganisms on the surface" classified in B08B 17/00. Moreover, the term fouling is very broad and appears to cover also processes as "rusting" (C23F 11/00) and "formation of scale" (C02F).

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Incrustation of metallic material
Accumulation of deposition /precipitation of undesired solid /dense products on a metallic surface in systems in which a fluid circulation takes place, preferably a water-based fluid circulation takes place, e.g. deposition /precipitation of compounds of calcium, magnesium, barium or strontium (carbonates/ sulphates), iron, lead, zinc sulphide, zinc, cadmium carbonates (white rust).
Synonyms and Keywords

In patent document the following abbreviations are often used:

Incrustation
encrustation, crust, carbonate/sulphate scale, lime scale, sulphide scale, aluminosilicate scale, oxalate scale., white rust.

In patent document the expression/word "inhibiting incrustation in general" is often used with the meaning: "inhibiting incrustation of metallic material "

Other methods of preventing corrosion or incrustation
Definition statement
This subclass/group covers:

Other methods of preventing corrosion or incrustation, e.g. by removing the corrosive agent from the medium or rendering it non corrosive by neutralizing it (C23F 15/00).

Inhibition incrustations, e.g. in polymerization reactors (EP1501910), in waste liquid line of an autoanalyzer (EP1477811) (C23F 15/005).

Other apparatus for executing the methods mentioned above as far as they are specially adapted for treating metallic material (C23F 15/00).

References relevant to classification in this group
This subclass/group does not cover:
Methods for preventing fouling
Informative references
Attention is drawn to the following places, which may be of interest for search:
Evaporating
Distillation
Crysatllization
Chemical, physical, or physico-chemical processes carried out with a view to control or to change the pH- value; Application of buffer salts; Neutralisation reactions
Processes of separation, e.g. by filtration, ultrafiltration, dialysis, osmosios
Mechanical methods for preventing fouling in hull protection
Treatment of water, waste water, or sewage by degassing (liberation of dissolved gases)
Treatment of water, waste water, or sewage by electrochemical methods for prevention or elimination of deposits
Treatment of water, waste water, or sewage with magnetic or electric field for prevention or elimination of deposits
C02F1/48C
Treatment of water, waste water, or sewage by addition of specified substances, e.g. by addition of complex-forming compounds
Treatment of water, waste water, or sewage by oxidation
Preventing scale by precipitation of the hardness
Compositions for preventing, limiting or eliminating depositions
Anti-oxidant compositions; Compositions inhibiting the chemical change
Preventing or removing incrustations in thermal non-catalytic cracking
Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils
Use of additives to fuels or fires for minimising corrosion or incrustation
Inhbiting corrosion of metals by anodic or cathodic protection
Means for protecting offshore constructions against corrosion
Devices and methods for diminishing corrosion in steam boilers
Preventing the formation of deposits or corrosion in heta-exchangers , e.g. by protective currents
Special rules of classification within this group

A clear difference has to be made between the word "fouling" with the above meanings and the word "fouling" used with the meaning " accumulation of particulates of microorganisms of the surface" classified in B08B 17/00.

A clear difference has to be made between the word "scale" with the above meaning and the word "scale" used with the meaning "white rust" "staining", "incrustation" "carbonate, sulphate, sulphide, silicate, oxalate scale" or "hydrocarbon scale" classified in C23F 14/00, C23F 15/00.

Synonyms and Keywords

In patent documents the expression "fouling" is sometimes used with the meaning " incrustation" or "rusting".

In patent documents the word "scale" is sometimes used with the meaning "rust" or " scale from ferrous metals, copper or aluminium alloys" or "rust staining".

Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 (C23C 28/00 takes precedence)
Definition statement
This subclass/group covers:

Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25.

References relevant to classification in this group
This subclass/group does not cover:
Coating for obtaining at least two superposed coatings by combinations of methods provided for in subclasses C23C and C25C or C25D
Informative references
Attention is drawn to the following places, which may be of interest for search:
Modifying the physical structure of ferrous metals; General devices for heat treatment of ferrous or non-ferrous metals or alloys; making metals malleable by decarburisation, tempering or other treatment
Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
After-treatment of hot-dipped or immersed coated metal surfaces
After-treatment of sprayed coated metal surfaces
Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, e.g. diffusion coatings
After-treatment of vacuum evaporated coated metal surfaces
After-treatment of chemical vapour deposited coated metal surfaces
After-treatment of electroplated surfaces
Special rules of classification within this group

The majority of documents classified in C23F 17/00 are also classified with at least one of the above mentioned subclasses /groups. In many cases the classification of invention information is only classified in the most appropriate place, namely, in only one of these subclasses /groups, with no need to also classify in C23F 17/00. This practice is very desirable, although not compulsory. As far as the combination of process steps defined as in the title of C23F 17/00 is important (invention-like information), these documents belong also in this class.

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Last Modified: 10/11/2013