Micro-scale abrasive wear of silicon nitride, sialon-TiB2 composites and D2 tool steel using a multiple load method

The addition of TiB2 to sialon has previously been shown to lead to improvements in tribological performance when using pin-on-disc testing. In this study the specific wear rates of Si3N4, sialon-TiB2 composites and D2 tool steel have been measured using micro-scale abrasive testing. Two variations of the micro-scale abrasive wear test have been used, free ball and fixed ball, and the results are compared. A method has been developed for the accurate measurement of the specific wear rate using multiple loads on the fixed ball apparatus. The multiple load method eliminates the dependence of the result on the accuracy of the balancing of the load arm. Scanning electron microscopy has been used to study the active wear mechanisms and the effect of increasing the applied load. The “severity of contact” model has been evaluated as a method for predicting the transition from three body rolling wear to two body grooving wear with varying load. Increasing the applied load led to slurry starvation and ridge formation before the predicted two body grooving wear could occur.