TRIBOLOGICAL BEHAVIORS OF THE DIAMOND-COATED CEMENTED CARBIDE TOOLS WITH VARIOUS COBALT CONTENTS

Tribological behaviours of diamond films deposited on cemented carbide substrates with various cobalt contents from 6% to 27% were investigated. The diamond films were deposited by a hot filament chemical vapor deposition (CVD) system. The effect of cobalt content and the surface pretreatments on nucleation, growth and properties of the diamond films were determined. The surface compositions and morphologies before and after surface pretreatments and deposition were characterized by EDX and SEM. The indentation adhesion tests were used to evaluate the adhesion of the films; and the block-on-ring method was adapted to determine their tribological properties. The experimental results show that the substrate with a low cobalt content exhibits a stronger adhesion, smoother surface, lower friction coefficient without adding lubricant, and better cutting performance. © 1992.