Filiform Corrosion Mechanism Of The Aluminum Alloy Surface

In this paper, commonly used material of aluminum car wheels was researched for the study, by using electrochemical measurement method for the determination of electrochemical parameters, thus the filiform corrosion resistance was assessed, at the same time using the method of mathematical processing the filiform corrosion degree of the surface of aluminum alloy wheel hub for quantitative evaluation. The development of dynamics of filiform corrosion of aluminum alloy was studied, and the different corrosion protection methods were evaluated and researched. In this paper, the main research contents and conclusions are as follows:Commonly used in automobile wheel hub series of A356 aluminum alloy as the research object, using different aluminum alloy process preparation of sample. Mainly through the study of the different pretreatment process of aluminum alloy, mainly including acetone degrease, alkali wash, pickling, chrome processing and different process, Annealing process of aluminum alloy were studied at the same time, including homogenization, heat treatment before tempering treatment etc, and half after annealing and full annealing heat treatment. Series of A356 aluminum alloy under different surface pretreatment and heat treatment process, using the dynamic scanning polarization and ac impedance technology of aluminium alloy samples to identify filiform corrosion resistance, the biggest silk long filiform corrosion of aluminum alloy, the number of average wire length and different wire for quantitative evaluation. Analysis of series of A356 aluminum alloy material coating filiform corrosion dynamic law of development, study the influence of different treatment on the corrosion resistance of aluminium alloy. Through the induction, deductive reasoning method to study the thermodynamics and kinetics of the filiform corrosion mechanism.Experiment showed that acetone oil removal, the combination of alkali wash, pickling, chrome handle before treatment scheme can significantly improve the filiform corrosion resistance of aluminum alloy, the acetone in addition to oil, alkaline cleaning, acid pickling is to clean up the second phase particles on the surface of aluminum alloy, chromium treatment can obviously promote the filiform corrosion resistance of aluminum alloy ability. Full annealing is combined with homogenization heat treatment can improve the dislocation density of the aluminum alloy surface and the enrichment degree of surface elements, make chemical conversion film on the surface of the aluminum alloy is more even, improve the ability of the filiform corrosion resistance of aluminum alloy.