| By development of a new process combining plasma nitriding process and MO-PACVD process, plasma nitrided+Ti(NCO) composite coating was formed on SKD11 tool steel. Using established process parameters obtained from previous research, the composite coating with superior mechanical and electrochemical properties was produced at relatively low deposition temperature of around 500℃ without softening and distortion of SKD11 substrate. The characteristics of the composite coating such as adhesion strength, microhardness, friction coefficient, wear and corrosion resistance were investigated. The hardness of composite coating was H_v2150. The corrosion potential of composite coating increased from -0.2V to -0.08V and the corrosion current decreased about 100 times in comparison with that of nitrided layer. Adhesion strength of composite coating determined by scratch adhesion test was over 100N which was roughly twice of that of Ti(NCO) coating. |
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