Correlation between the tribological behaviour and wear particle morphology - case of grey cast iron 250 versus graphite and PTFE

Wear particles are produced as a result of interaction of two surfaces in mechanical systems. After extracting and separating particles by different techniques (filtration, ferrography...), their morphology, which is a function of the condition of tribological system (tribosystem), can be related directly to the wear process. In order to understand wear mechanisms, it is interesting to study the relationship between the characterization of wear particles (aspect ratio, shape factor, spike parameter) and the mechanical factors of wear. Therefore, a series of tests were conducted with polytetrafluoroethylene, (PTFE) versus cast iron, and flake graphite versus cast iron. Wear particles were studied in a particular tribosystem to understand debris formation and wear. Consequently, after friction tests according to a plane on plane contact, wear particles were collected. After separation tests, particle morphology obtained through image analysis techniques, was used to determine how debris are produced and to elucidate wear mechanisms. Finally, we propose a wear mechanism with these particular tribosystems. (c) 2006 Elsevier B.V.. All rights reserved.