Effect Of Surface Nanocrystallization On The Corrosion Performance Of Cu-10Ni Alloy And Its Application In Lithium Ion Batteries

Because Cu-10 Ni alloy has good properties,such as conductivity,workability and corrosion resistance,it is widely used in the marine environment.The failure of Cu-10 Ni alloy mainly occurs on the surface,and corrosion and wear are the main ways of its failure,which seriously affects its service life.Therefore,further improving the corrosion resistance of Cu-10 Ni alloys has become an important engineering issue.Surface nanocrystallization(SNC)technology is a common technology for improving the performance of metal materials and extending the service life.In this paper,through experimental and theoretical research,the best preparation process for the surface nano-nickel alloy with high corrosion resistance was obtained,which laid the foundation for its popularization and application.The research results are of great significance to guide the corrosion mechanism of white copper and enrich the theory of nanocrystalline corrosion.Copper alloys can also be used as negative electrode current collectors in lithium-ion batteries,but they are prone to corrosion during use,resulting in shortened service life and affecting battery stability.Therefore,it is of great significance to prepare a current collector with high corrosion resistance and stable circulation performance.Nanometering can improve the corrosion resistance of the copper alloy,increase the specific surface area in contact with the active material,effectively reduce the absolute volume expansion rate of the active material during charging and discharging of the battery,enhance the contact with the electrolyte,and improve the conductivity.In this paper,Ultrasonic Shot Peening(USSP)and Ultrasonic Surface Rolling Process(USRP)were used to nano-process the Cu-10 Ni alloy to obtain an alloy with a gradient nanostructured surface layer.The structure and properties of the surface nanolayers were characterized,and the corrosion behavior of Cu-10 Ni alloy in 3.5 wt.% NaCl solution before and after surface nanocrystallization treatment was also studied.On this basis,the Cu-10 Ni alloy subjected to ultrasonic surface rolling treatment was applied to the negative electrode current collector of lithium ion batteries,and the corrosion performance and battery performance of the Cu-10 Ni alloy current collector were preliminarily studied.Research indicates:(1)Ultrasonic shot peening equipment is used to process Cu-10 Ni alloy.With the increase of shot peening time,the grain size becomes finer and the hardness increases.The thicker the deformed layer on the surface.The electrochemical corrosion behavior of ultrasonic shot peened Cu-10 Ni alloy in 3.5 wt.% NaCl solution was found.The radius of curvature of the impedance spectrum of the sample after ultrasonic shot peening increased,the polarization curve corrosion potential shifted positively,and the corrosion current density decreased Small,improved corrosion resistance.(2)After the ultrasonic surface rolling treatment,the average particle size of the outermost layer of the Cu-10 Ni alloy is 70 nm,which realizes nanocrystallization.The surface hardness is increased by about 80% compared with the matrix hardness,and the cross-sectional hardness changes gradually.The electrochemical polarization curve after surface nano-treatment has a clear passivation platform,and the corrosion current density is smaller,and the corrosion voltage is larger than the original sample,indicating that the corrosion resistance of the sample after nano-treatment is improved.The radius of the impedance spectrum of the original sample is smaller than that of the nanometer,indicating that the corrosion rate of the nanometer sample is small.(3)Ultrasonic surface rolling treatment can obtain a nanocrystalline layer with a surface grain size of about 70 nm,which is used as a copper alloy current collector in the negative electrode of a lithium ion battery.The results of electrochemical impedance and polarization curves show that the surface nanometer The corrosion resistance of the copper alloy current collector in the electrolyte of the lithium ion battery is better.Atomic force microscopy(AFM)test shows that the surface of the nano-treated copper Cu-10 Ni alloy current collector is rougher than the original sample surface and the specific surface area increases.At the same time,the specific capacity of the current collector electrode is greater than the original sample and maintains a higher cycle stability And good rate performance.