SLOW CRACK-GROWTH OF CVD DIAMOND

Slow crack growth in CVD diamond has been observed from indentation experiments. Diamond films of 400-mu-m thickness were prepared by plasma-enhanced CVD on a silicon substrate, subsequently removed from the substrate, and polished for indentation testing. A microhardness tester was used to produce Vickers indentations under low load. Crack length measurements over time revealed susceptibility to slow crack growth in ambient testing conditions. The stress-corrosion susceptibility coefficient, N, was measured as 9.3.