Influence of Saccharin Sodium on Microstructure and Performance of Electrodeposited Nanocrystalline Ni Coating

摘要

Nanocrystalline nickel (nc-Ni) coatings were prepared by pulse electrodeposition method. Their structure was investigated by SEM, TEM and XRD, and their microhardness, thermal stability and corrosion resistance were studied by a microhardness tester, DSC and potentiometer respectively. It is found that the grain size of nc-Ni coating decreases with the increased, the smallest grain size is achieved at 10g/L. With a saccharin concentration less than 15 g/L in electrolyte, the surface of the electrodeposit is smooth and bright. The microhardness of nc-Ni coatings reaches the tops when content of C7H4NO3SNa-2H2O is 10g/L. The relationship between the grain size and microhardness fits for the Hall-Petch function, approximately. The instability growth temperature of nc-Ni coatings is slightly fluctuated at 305°C under different content of C7H4NO3SNa-2H2O.The corrosion resistance of nc-Ni coatings is optima when the content of C7H4NO3SNa-2H2O is 10g/L.