Analysis of silicon nitride bearings with laser ablation inductively coupled plasma mass spectrometry

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for the analysis of silicon nitride ceramic bearings. Since calibration standards are not readily available for silicon nitride as well as many other ceramic materials, several calibration strategies have been assessed. Solution standards and a National Institute of Standards and Technology (NIST SRM) glass were demonstrated to be useful for the determination of trace and minor constituents in the bearings. Results for minor bearing constituents were verified with electron probe microanalysis (EPMA). Profilometry and weight loss measurements indicated that approximately 2 ng of silicon nitride was removed by each laser shot and that the efficiency of the LA-ICP-MS system was approximately 1 ion detected per 500 000 atoms removed for the Mg sintering aid present in these bearings.