| 摘要 |
<p>Hard metal substrate (a) has a coating (b) built up from cpds. of Ti with carbon and nitrogen. The max. of nitrogen content in coating (b) occurs near substrate (a), whereas the max. carbon in coating (b) occurs at the outer surface of this coating (b). A boundary zone of titanium carbonitride may exist between substrate (a) and coating (b). The pref. mfg. method uses gas phase depsn. via a mixt. of N2, Ti halide and H2, producing a boundary zone (ab) due to carbon diffusing from substrate (a) to form Ti-C-N, and then TiN; a mixt. of hydrocarbon gas, Ti halide and H2 is finally used to form an outer layer of pure titanium carbide. The N2 in the initial gas mixt. may be gradually replaced by the hydrocarbon, which is esp. methane. Better toughness is obtd. combined with reduced wear and reduced formation of craters on the tool surface.</p> |
