Controlling the thickness of coatings on steel is critically important in many industries, including nuclear power generation, transportation infrastructure (railway and steel bridge), the military, automotive, and the surface finishing with decorative coatings. The control is essential both to ensure performance and to minimize waste. For many years the Metallurgy Division in MML has supplied industry with Coating Thickness Standard Reference Materials (SRMs) enabling calibration of the instruments used to measure coating thickness.
Recently we conducted a study of our customer base to determine their anticipated needs. The study included input from instrument manufacturers, secondary standard manufacturers, distributors, and current customers of similar standards, NIST's SRMs series 1358 through 1364. The results of the survey indicated that NIST could effectively meet industrial needs by supplying higher accuracy SRM's directly to instrument manufacturers and secondary calibration laboratories, rather than to end users.
As a result, the Metallurgy Division, in conjunction with the Precision Engineering Division of the Manufacturing Engineering Laboratory (MEL), has begun fabricating the next generation coating thickness SRM. Compared to the existing SRM, it will have more coupons per set, coating thicknesses ranging from micrometers to millimeters, and a smaller measurement uncertainty. These enhancements will enable secondary standard manufacturers to demonstrate traceability to NIST while producing standards of quality similar to that of the existing NIST SRMs.