Residual Stresses and Strength of Cemented Carbides Coated With TiN by Plasma CVD Process, Comparing with that of Thermal CVD Process
The properties of TiN coated cemented carbides are differed from coating method in cohesive strength and in failure resistance. There are several methods that are applied in practical uses. The thermal CVD coated cemented carbides with TiN have an excellent cohesive strength between the coated TiN film and the WC-Co substrate but it is inferior in the failure resistive properties. On the contrary, the PVD coated cemented carbides with TiN are superior in failure resistive properties but the cohesive strength is deteriorated comparing with CVD coated alloys. These difference are dominated by some differences of forming mechanism of the deposit. The residual stresses had been measured and i t was made clear that tensile stresses was produced in CVD coated alloys which lead to cracking of the coated alloys and compressive stresses was measured in PVD coated alloys. These surface stresses have an important effects on fracture strength of the TiN coated cemented carbides. In this paper, the residual stresses of cemented carbides coated with TiN by plasma CVD process which is considered as a compromising method of CVD with PVD process are reported comparing with that of CVD and PVD coated alloys.
KeywordsResidual Stress Cohesive Strength Cement Carbide Glow Discharge Plasma Coated Alloy
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