Influences of pulse electrodeposition time on microstructure and performance of nanocrystalline nickel plating

Nanocrystalline nickel plating was prepared by pulse electrodeposition method.The microstructure,microarea composition,structure and mechanical properties of nanocrystalline nickel platings under differernt electrodeposition time were characterized and analyzed with SEM,EDS,XRD and microhardness tester.The results show that the grain sizes of nickel platings prepared under different electrodeposition time slightly fluctuate at 21 nm.The microhardness values of nickel platings first increase and then slowly decrease with the electrodeposition time prolonging,the maximum value is 472 HV0.01 when the electrodeposition time is 16 min.The micro-morphology of nanocrystalline nickel is cumulative grew cellular structure,the surface of cellular structure is densely covered by second nanocrystalline nickel particles with size of about 90 nm when the electrodeposition time is 1-4 min.The initial temperature is 283.7 ℃,and the peak temperature is 311.4 ℃,when the nickel plating unstablely grows up in this experiment.