直流电沉积和脉冲电沉积Ni-W涂层的对比.pdfVIP

Rare Metal Materials and Engineering Volume 41, Suppl. 2, September 2012 Cite this article as: Rare Metal Materials and Engineering, 2012, 41(S2): 707-710. Synthesis and Evaluation of Pulse Current and Direct Current Electroplating Ni-W Coatings on Steel Wang Meiling, Yang Zhigang, Liu Dianlong, Zhang Chi, Wang Zhenqiang Key Laboratory of Advanced Materials, Ministry of Education, Tsinghua University, Beijing100084, China Abstract: Pulse current (PC) and direct current (DC) electroplating Ni-W coatings have been prepared and the composition, morphology, and structure of these coatings were investigated by energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), respectively. It is verified that the PC Ni-W coatings present uniform surface and dense structure, as well as higher hardness and corrosion resistance than DC electroplating Ni-W coatings. PC Ni-W coatings with more than 20at% W yield a nanocrystalline structure. The maximum HV hardness of PC Ni-W coatings achieves 7.26 GPa for the sample with the highest W content. Moreover, the corrosion rate of PC Ni-W coating after neutral salt spray test for 120 h is comparable with that of DC electroplating Cr coatings, which is better than that of DC electroplating Ni-W coatings. Key words: pulse current; Ni-W coatings; hardness; corrosion resistance Ni-W coatings have attracted intense interest in recent immersed in the electroplating bath. The bath compositions years due to their excellent properties, which can be used as and parameters of PC electroplating were as follows: 0.025 environmentally safe substitute for hard chromium plating mol/L NiSO ·6H