Wear debris and associated wear phenomena—fundamental research and practice

The effect and consequences of wear on the present-day operation and maintenance of industrial machinery are considerable and far reaching in terms of the performance, cost and underlying business environment. One of the ways open to maintenance engineers to keep track of the wear occurring is to monitor the condition, or ‘health’, of critical items of machinery by either measuring or capturing representative samples of wear products, primarily the debris that is generated in the contact which is subsequently released and transported away from the source by the lubricant behaving as a carrier fluid. Commencing with a brief description of some wear-related failures of critical components, such as bearings and gears, the different manifestations of wear debris are reviewed with particular regard to the methods employed to measure or capture the debris and how their characteristics are determined. Of particular importance is the need to establish and single out those morphological features which relate to the underlying wear mechanisms involved which led to their generation. The manifestation of wear phenomena and the causal effects are to be addressed by examining the mechanisms in the light of current fundamental research in which the links between wear and the generation of the associated debris are reviewed and discussed.