Patent ID: 6377039
Filing Date: 2002-04-23
Classification: G01B

Abstract:
A method for determining properties of a coating and substrate of a material under test comprising the steps of:placing a sensor in proximity to the material under test; introducing a drive signal into the sensor at multiple frequencies; measuring the sensor output at the multiple frequencies; converting the sensor output to measured physical parameters of the material under test at each of the multiple frequencies, the measured physical parameters being conductivity (&sgr;) and lift-off (h); estimating the substrate and the coating conductivities (&sgr;) from a limit of conductivity at a low frequency and a limit of conductivity at a high frequency; generating thickness-liftoff grids from the estimated conductivities; computing lift-off or thickness of the coating from the thickness-liftoff grids; and plotting liftoff or thickness as a function of frequency; adjusting the estimate of the substrate and the coating conductivities if indicated by the liftoff or thickness plot.