Volume 4, Issue 10 (November 2007)
Prospects for Adapting Current ASTM Wear and Erosion Tests for Bulk Materials to Thin Films, Coatings, and Surface Treatments
Most of ASTM Committee G2’s erosion, wear, and friction test standards were developed for use with bulk materials, yet there is a growing need to evaluate the tribological behavior of films, coatings, and surface treatments (FCSTs), some that affect layers only tens of nanometres to a few micrometres thick. Tribotesting standards for bulk materials can sometimes be modified for use on FCSTs, but the conditions and methods developed for bulk materials may sometimes be too severe or inapplicable. An Internet search and literature review indicated that a number of G2 Committee standards are currently being used for FCSTs. Of these, ASTM G 99 and G 65 seem to be the most popular. When attempting to apply an existing wear standard for bulk materials to FCSTs, two key issues must be addressed: (1) whether changes are needed in the magnitudes of the applied conditions, and (2) whether more precise methods are needed to measure the magnitude of surface damage. Straightforward calculations underscore the limitations for wear measurement of thin layers when evaluated using block-on-ring and pin-on-disk tests. Finally, suggestions are given for modifying selected ASTM G2 standards to enable their use on films, coatings, and surface treatments.