Abstract
A new multiple chemical-pretreatment for K10 drills was developed and by which the diamond films with high adhesive strength could be obtained in the electron aided hot filament chemical vapor deposition (EACVD) process. The pretreatment was especially suitable to the substrates with complex geometries. It was consisted of microwave oxidation, alkaline reaction, and cleaning in acid solution. Adhesive strength and quality of diamond films were evaluated by SEM, AFM, XRD, Raman spectrum, and drilling experiments. The friction coefficient increased with the surface roughness of the diamond films. A new multiple coating technology based on varying parameters was also developed and by this the diamond-coated drills were of both high adhesive strength and low surface roughness. The multiple diamond-coated drills yielded longer tool life and smoother holes than those of the conventional diamond-coated ones. The wear mechanism of diamond-coated drills is the abrasive mechanical attrition.
