The Research Of One-step Pretreatment Techniques And Rapid Exchange Electrolytic Golden Technology On Aluminum Alloy

In this paper,three-in-one pretreatment and anodizing AC electrolytic coloring process of aluminum alloy are studied.The three-in-one pre-treatment process can be used to remove oil,oxide skin and light in one step.The optimum process is as follows:sulfuric acid is 5-10g/L,hydrofluoric acid is 10-15g/L,additive is 2-5g/L,polyethylene glycol is 1.5g/L,surfactant is 0.02-0.05g/L,temperature is 25-30?,time is 3-5min.The anodic oxidation and coloring process of aluminum alloy were determined by single factor experiment with electrochemical performance as the research and evaluation method,and the optimum technological conditions of anodic oxidation and fast coloring of aluminum alloy were found out.By means of corrosion weightlessness test,electrochemical test,metallographic observation,SEM characterization and impact test,the properties of anodic oxidation and coloring corrosion resistance,electrochemical performance and binding ability of aluminum alloy were studied.The optimum conditions for anodic polarization of aluminum alloy are as follows:sulfuric acid concentration is 190g/L,treatment temperature is 20?,oxidation current density is 4.0 A/dm² and oxidation time is 30 min.The optimum conditions for fast coloring aluminum alloy are as follows:potassium permanganate is 15g/L,sodium persulfate with material A is 5g/L,pH is0.8,coloring voltage is 10V,treatment time is 5 min.The polarization curves of aluminum alloy samples were measured.The self-corrosion current density of the colored and anodized aluminum alloy samples is two orders of magnitude and one order of magnitude lower than that of the deoxidized aluminum alloy sample,respectively.The results show that the corrosion resistance of the oxidized aluminum alloy is improved.The results of XPS analysing show that the coloring film is mainly composed of Al?Mn?O?Na,the main composition of the colored film is Al₂O₃,MnO₂ and complex oxide of Mn.And the resualts of impact test show that the coloring film is better adhere to paint film than the anodized film.The results of metallographic and SEM observation show that the surface of aluminum alloy treated by anodic oxidation has honeycomb shapes,and that treated by coloring after anodizing has dendritic structure.And then,patterned surface indicates that the metallic element is effectively deposited on the surface of the colored aluminum alloy.The wear resistance test results show that the wear resistance of the colored aluminum alloy was greatly improved.Finally,this paper summarizes and analyzes the operating standards of anodizing and coloring of aluminum profiles in the industrial production process,and designs a related management scheme to guide production.