Abstract
The transverse-rupture strength of WC-5, 10%Co alloys coated with a titanium carbide (TiC) layer of 2-10 /μm by CVD process was investigated in relation to the carbon content of substrate alloys. Substrate alloys were ranged from two-phase to three-phase ones containing free carbon.
It was found that the strength of coated alloys did not almost change according to the carbon content of substrates, in contrast to the strength of substrates. This phenomenon was due to the fact that the thickness of n-containing layer formed at the interface between TiC layer and substrate became thinner with increasing carbon contents at a fixed thickness of TiC layer, so that the decrease in the substrate strength with increasing carbon content was compensated. In addition, when free carbon contained substrates were applied, it was noted that TiC layer was fine-grained and rich in dissolved tungsten, and cobalt layer was formed at the interface.
