Influence of Temperature on Corrosion Resistance of Vacuum Nitriding Layer on 7075 Al-alloy

7075 aluminum alloy was vacuum-nitrided at 480 ～540 ℃,and the samples before and after nitrided were processed by copper accelerated salt spray corrosion test.The corrosion rates of the samples in salt fog environment were examined with the method of mass loss and maximum corrosion depth.The corrosion features of the samples was studied by photos,SEM and PDS.The results show that the vacuum nitriding can improve the corrosion resistance of 7075 aluminum alloy;the vacuum nitriding layer at 500 ℃ has the best corrosion resistance.