The determination of iron in lubricating oils by X-ray fluorescence spectrometry

Abstract

The measurement of iron in lubricating oils taken from an experimental gear rig and various truck assemblies has been examined by X-ray fluorescence (XRF) spectrometry. This simple and rapid technique is shown to give accurate and reproducible results for these systems. Particle size limitations were found not to be as severe for XRF as is evidently the case for spectrometric oil analysis methods, and XRF appears to be more suitable for the detection of the relatively large particles which are indicative of the onset of severe wear. Iron contents of from 1 to 1200 wt.ppm in oils were measured with results in agreement with those obtained by atomic absorption spectrometry after a wet-ashing procedure, but they were higher than those obtained by direct atomization. To obtain reliable XRF results the reference solutions used were prepared from the same oil as that in the assembly under test.