材料期刊网

A CrN/Cr(1-x)Al(x)N coating comprised of an inner layer of CrN and an outer layer of Cr1(1-x)Al(x)N with a gradient distribution of Al was deposited on two different alloys by a reactive sputtering method. Oxidation and hot-corrosion tests of the gradient CrN/Cr1(1-x)Al(x)N coating were performed at different temperatures. The phase compositions and morphologies of the as-deposited coating and the corrosion products were investigated by using XRD and SEM/EDS. The results showed that the gradient CrN/Cr1(1-x)Al(x)N coating exhibited good oxidation resistance at temperatures above 1000 degrees C owing to the formation of an alpha-Al(2)O(3)-rich oxide scale. The coating possessed good hot-corrosion resistance in molten sulfate because the inner CrN layer could supply enough Cr to form a relatively protective Cr(2)O(3) after the Al(2)O(3)-enriched scale failed due to its dissolution in the molten sulfate.