THE ABRASION RESISTANCE AND ADHESION OF HFCVD BORON AND SILICON-DOPED DIAMOND FILMS ON WC–Co DRAWING DIES

Abstract

Diamond films have been deposited on the interior hole surface of cobalt-cemented tungsten carbide (WC–Co) drawing dies from acetone, trimethyl borate (C3H9BO3), tetraethoxysilane (C8H[Formula: see text]O4Si, TEOS) and hydrogen mixture by hot-filament chemical vapor deposition (HFCVD) method. The structures and quality of as-deposited diamond films are characterized with field-emission scanning electron microscopy (FESEM) and Raman spectroscopy. The abrasion ratio and the adhesive strength of as-deposited diamond films are evaluated by copper wire drawing tests and ultrasonic lapping tests, respectively. The results suggest that diamond films with small grain size and high growth rate can be obtained due to the mutual effects of boron and silicon impurities in the gas phases. The results of ultrasonic lapping tests show that diamond films doped with boron and/or silicon can bear the severe erosion of the large diamond powder. Diamond films peeling off within the reduction zone of the drawing dies cannot be observed after testing of 2[Formula: see text]h. The abrasion ratio of boron and silicon-added diamond films is five times that of diamond films without any addition. Adding boron and/or silicon in the diamond films is proved to be an efficient way to obtain high-adhesive-strength and high-abrasion-resistance diamond-coated drawing dies.