Auger electron spectroscopy of wear surfaces

Abstract

THE effectiveness of lubricants containing sulphur and/or chlorine compounds in preventing wear and seizure of steels is related to the chemical lability of the load-carrying element (sulphur, chlorine) contained in them¹. This finding is consistent with the formation of surface layers of iron sulphide and chloride which prevent metal wear and seizure. Little could be deduced, however, about the nature of these protective layers. We investigate here the surface region of wear scars formed in the four-ball lubricant testing machine using Auger electron spectroscopy (AES) incorporating an argon ion sputtering technique. Here a beam of argon ions is used to etch away surface layers, and expose underlying layers for examination by AES. Using these techniques we can build up an approximate composition profile for the surface region of the sample. This was a more detailed investigation than that by Buckely², who used AES principally to investigate changes in the surfaces of loaded disks.