DEPTH PROFILE STUDIES USING LASER-INDUCED PLASMA EMISSION-SPECTROMETRY

The application of laser-induced plasma emission spectrometry to the d epth profile measurement of coatings on steel is examined. The effects of key experimental parameters, such as laser energy and sample posit ion relative to the laser focal point, on depth profile performance we re characterized for a Zn/Ni coating on steel. With preferred operatin g conditions, linear calibrations against coating thickness for Zn/Ni (2.7 to 7.2 mu m) and 59 (0.38 to 1.48 mu m) on steel were achieved wi th good precision (3.5% relative standard deviation). An ultra-thin co ating of Cr (20 nm) on steel was also detected by the technique. The d epth profile performance and rapid measurement times, typically less t han 60 s, indicate that the technique may be useful in industrial appl ications.