Abstract
The probability of surface hardening by a plasma nitriding process was investigated for tentative Cu binary alloys containing Al, B, Cr, Fe, Mn, Si and Ti at nitriding temperatures of 773 to 1173K and nitriding times of up to 43.2ks in an N2+H2 mixed gas atmosphere at 800Pa.
Surface hardening was observed in Cu-Ti and Cu-Mn binary alloys at nitriding temperatures of 1023 to 1173K. Maximum surface hardness was Hv 350∼500 for alloys containing Ti and Mn containing alloys of more than 5 and 10wt% respectively. Cu-Al, Cu-B, Cu-Cr, Cu-Fe and Cu-Si binary alloys, however, were not hardened.
A nitrided layer was observed in alloys showing surface hardening as Cu-Ti and Cu-Mn binary alloys. From the results of EPMA and X-ray diffraction analysis, it was estimated that a nitriding layer was formed as a nitride compound layer consisting of TiN for Cu-Ti and Mn4N for Cu-Mn. Surface hardening is thus attributed to the formation of a nitrided compound layer on the surface of the specimen.
