Article ID Journal Published Year Pages File Type
620095 Wear 2007 10 Pages PDF
Abstract

The nanomechanical properties of antiwear films formed from zinc dialkyl-dithiophosphates (ZDDPs) on steel have been studied by nanoindentation techniques as a function of temperature. X-ray absorption P K- and L- near edge structure (XANES) spectroscopy has shown that films prepared from oils containing ZDDPs on 52100 steel (pin on flat coupons) consist primarily of medium chain polyphosphates with sulphur (S K-edge) predominantly present as sulphide.Using various scanning probe techniques, high-resolution topographic images and mechanical properties can be extracted at the same length scale. Using focused ion beam (FIB) milling we have compared real cross-sectional film thickness with a value estimated from the P K-edge XANES. We report the first measurements of the elastic modulus of the antiwear films at elevated temperatures relevant to the automobile operating conditions (T ≤ 200 °C). The antiwear films demonstrated a relatively constant indentation modulus over a wide range of temperatures consistent with their efficacy in reducing wear by preventing asperity contact.

Related Topics
Physical Sciences and Engineering Chemical Engineering Colloid and Surface Chemistry
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