Integrity of Wear Coating Subjected to High-Speed Asperity Excitation

摘要

When hard coatings are designed to protect substrates against the high speedfrictional excitation of asperities, it is important to consider parameters that would affect the integrity of the coating. Thermo-mechanical cracking and coating delamination are the major failures of hard coating. In analytical modeling, it is important to know the limitation of the model and the validity of the conclusions drawn from the analysis. The report addresses the postulation of a two-dimensional model, which is used for the mathematical simplicity to study the effects of various parameters. For high speed asperity excitation, thermal stress dominates the analytical criteria. The report considers the effect of coating thickness and its critical value. Material parameters are grouped into those of mechanical properties and those of thermal properties. The differences of those properties between the coating and the substrate directly affect the integrity of the coating. Irregularities, especially in the neighborhood of the coating/substrate Interface, are introduced to study their damaging effects to the coating integrity.