The effects of compressive stresses on the abrasion of diamond coatings

The effects of high biaxial compressive stresses on the abrasion of diamond coatings by diamond particles were evaluated using an atomic force microscope (AFM). The specimens subjected to testing were diamond coatings deposited on cemented carbide substrates, receiving high biaxial stresses due to thermal expansion mismatch, and freestanding stress-free diamond coatings. It is shown that the highly stressed coatings obtain a smoother worn surface and a significantly lower wear rate as compared to the stress-free coatings. Thus, biaxial stresses increase the inherently high wear resistance of diamond coatings. The results agree with a previously proposed model for the effect of high biaxial compressive stress on the abrasion of brittle coatings.