Combining thermo-diffusing titanium and plasma nitriding to modify C61900 Cu-Al alloy

To improve the mechanical properties of C61900 copper-aluminum alloy, a multi-phases coating was fabricated by the combination of thermo-diffusing Ti film and plasma nitriding. The results showed that a smooth coating with fine and uniform grains could be achieved, and the 9 mu m thick multi-phases coating, containing Ti-Cu-Al intermetallics (CuTi2, CuTi, AlCu2Ti) and titanium nitride (Ti2N) formed on the nitrided surfaces. The surface hardness of the coating was obviously improved to be 630 HV0.01, and the cross-sectional hardness decreased gradually to that of C61900 Cu-Al alloy. Moreover, the wear rate of the coated specimen decreased significantly, dropping 95.5% compared with the untreated Cu-Al alloy. (C) 2016 Elsevier Ltd. All rights reserved.