The ternary electroless Ni-Cu-P and Ni-Ce-P coatings were prepared respectively on AZ 91D magnesium alloy substrate.Their samples were put into NaCl solution with a mass concentration of 3.5%and acetate solution with a mass concentration of 5%respectively to perform a comparative experiment for testing their corrosion resistance by weight loss method.The results show that the corrosion resistances of the Ni-Cu-P and Ni-Ce-P coatings in 5%acetate solution have been improved by 50 and 12.8 times respectively;...