US 7,483,152 B2
High resolution statistical analysis of localized corrosion by direct measurement
Vladimir Jovancicevic, Richmond, Tex. (US); and Samuel Everett Campbell, Richmond, Tex. (US)
Assigned to Baker Hughes Incorporated, Houston, Tex. (US)
Filed on Feb. 23, 2005, as Appl. No. 11/63,363.
Claims priority of provisional application 60/549826, filed on Mar. 03, 2004.
Prior Publication US 2005/0213430 A1, Sep. 29, 2005
Int. Cl. G01B 11/14 (2006.01)
U.S. Cl. 356—614 17 Claims
 
1. A method of measuring and analyzing localized corrosion of a substrate comprising:
locating a substrate in an orientation in a measuring apparatus;
taking height and spatial measurements of an initial surface area of the substrate within a height and spatial resolution to produce an initial digital surface map;
subjecting the substrate to a corrosive environment for a time period;
locating the substrate in the measuring apparatus in the same orientation;
taking height and spatial measurements of the same surface area of the substrate within the height and spatial resolution to produce a subsequent digital surface map;
subtracting the subsequent digital surface map from the initial digital surface map to give a measurement of extent of localized corrosion of the surface area; and
statistically analyzing the measurement of extent of localized corrosion to determine a characteristic selected from the group consisting of corrosion depth (penetration) rate, spatial pit distribution, average pitting rate, maximum pitting rate, and combinations thereof, in the absence of laser profilometry.