INFLUENCE OF EMBEDDED TUNGSTEN PARTICLES ON MECHANICAL BEHAVIORS OF CVD DIAMOND COATING

Abstract

Diamond coating has gained intensive attraction in the tribological field due to its high hardness. However, its weak flexibility always gives rise to the fragile crack, which causes the delamination and peeling off from substrate. In this work, a novel deposition method combining the conventional hot filament chemical vapor deposition (HFCVD) and particles doping technique is proposed to balance the hardness and flexibility of diamond coating, by which the diamond coating with tungsten particles is deposited on the co-cemented tungsten carbide substrate. The as-deposited diamond coating is characterized by scanning electron microscopy (SEM) analysis, surface roughness and Raman spectrum. The indentation tests are conducted to evaluate the crack propagation of diamond coating. Tribological behavior is examined on a reciprocating ball-on-plate tribometer. The results indicate that tungsten carbide may be formed between tungsten particles and diamond coating. The W–WC–amorphous carbon–diamond structural coating can validly inhibit the crack propagation and decrease the friction coefficient. Hence, adding embedding particles into the diamond coating may provide a useful way in enhancing the mechanical properties of diamond coating.