Quantitative measurement for the effect of enhanced nucleation on the adhesive strength of diamond coatings

Nucleation of chemically vapor deposited (CVD) diamond can be enhanced by a pplying negative bias voltage to the substrates. The bias-enhanced nucleati on of diamond was examined in this report for the case of microwave plasma CVD on cobalt-cemented tungsten carbide (WC-Co) substrates. Nucleation dens ity was enhanced up to 1 x 10(9) cm(-2), although the reproducibility of th e experiment was poor. Adhesive toughness of diamond films with different n ucleation density was measured by a new technique recently developed by the authors. The results suggest that the adhesion of diamond coatings on WC-C o substrates can be considerably improved by higher nucleation density as t he consequence of bias application. (C) 2001 Elsevier Science B.V. All righ ts reserved.