A system for gaging plating thickness

The nondestructive measurement of cladding thickness when the cladding metal and the base metal are nonmagnetic has presented a major problem for a number of years. There have been several different approaches to the problem such as ultrasonics, back scattering of beta or gamma rays, and eddy currents. At present, the eddy-current method appears to have the greatest chance for success. Several eddy-current instruments have been developed, but there is still a need for improved instruments.