Study On Corrosion And Wear Resistance Of Ni-Zn-Al Hydrotalcite Film On Aluminum Alloy Surface

Aluminum and its alloy have excellent physical and chemical properties.It is widely used in automobile,shipbuilding,3C electronics,aerospace,and other industries.Al alloy is also one of the manufacturing materials of automobile pistons,but the weak corrosion and wear resistance of aluminum piston makes it unable to run for a long time.Therefore,it needs to be improved to extend the service life.In addition to the improvement and optimization of the material itself,surface treatment is also a common material strengthening method.In this paper,nickel-zinc-aluminum hydrotalc film was in-situ grown on the surface of anodic aluminum oxide by hydrothermal method,and the film was modified to improve the corrosion resistance of aluminum alloy while reducing the friction coefficient,for aluminum alloy surface anticorrosion and antifriction composite film research and application to expand a new idea.NiZnAl-LDH film was prepared on anodic alumina surface by hydrothermal method.The effects of solution pH,temperature,and growth time on the film were investigated.The morphology,structural composition,corrosion resistance,and friction properties of the film were studied by SEM,EDS,XRD,XPS,FT-IR,electrochemical tests and friction experiments.The results show that the hydrotalcite membrane is composed of flower-like nanosheets with a thickness of about 10μm.When the pH of solution is 9,the temperature is 110℃,and the growth time is 24 h,the minimum corrosion current density of the film is 5.813×10^-7 A·cm^-2,and the corrosion resistance of the film is obviously higher than that of aluminum alloy.The friction coefficient of the film is about 0.35,which is lower than 0.6 for aluminum alloy and0.8 for anodic alumina.The NiZnAl-LDH film was intercalation ion exchange with sodium molybdate,and the effects of solution pH,temperature,and time on the film were investigated.The morphology,structural composition and corrosion and wear resistance of the film were studied.When NiZnAl-LDH is immersed in sodium molybdate solution with pH=9.5 for 2.5 h at 35℃,the minimum corrosion current density is 4.131×10^-8 A·cm^-2,which is one order of magnitude lower than that of the modified hydrotalc film.The friction coefficient of the film layer is about0.28.The NiZnAl-LDH film was surface hydrophobic modified by ricin oleic acid,and the effects of solution pH,temperature and time on the film were investigated.The morphology,corrosion resistance,and friction properties of the film were studied by using sodium molybdate and ricin oleic acid to modify hydrotalcite.The results show that when the pH of the modified solution is 4.0,the temperature is 35℃and the reaction time is 30 min,the minimum corrosion current density of the film is 1.931×10^-8 A·cm^-2,which is one order of magnitude lower than that of the modified hydrotalc film.The friction coefficient of ricinoleic acid modified film is0.25,lower than 0.35 before modification.Combined with intercalation ion exchange and surface hydrophobic modification to cooperatively modify hydrotalcite.The self-corrosion current density of the modified film is8.932×10^-9 A·cm^-2,which is an order of magnitude lower than that of the single modification.The friction coefficient of the co-modified film is 0.23,it also has a certain decrease compared with that of the single-modified film.