Preparation and Corrosion Resistance of Cerium Conversion Coating on the Surface of Aluminum Protective Coating

In order to improve the corrosion resistance of aluminum protective coating,Ce conversion coating was prepared on the Al protective coating from a modified Ce salt solution based on L9(34) orthogonal test.The conditions for preparing Ce conversion coating were optimized in relation to the investigation of corrosion resistance.It was suggested that the conversion solution consisted of 14.0 g/L Ce(NO3)3,0.3 g/L (NH4)2S2O8 and 0.3 mL/L accelerating agent.The optimized conversion conditions were suggested as pH value of 1.5～3.0,temperature of 25 ℃ and time of 25 min.Resultant Ce conversion coating had better corrosion resistance than Alodine1001 and was qualified for modification of Al protective coating on the surface of high-strength steel parts of aircrafts.