电镀制备镍–碳化钨复合电极及其抗电蚀性能

Preparation of nickel–tungsten carbide composite electrode and its electrical corrosion resistance

采用复合电镀工艺在纯铜棒表面制备了Ni–WC复合镀层。镀液组成和工艺条件为:NiSO_4·6H_2O 250~300 g/L,NiCl_2·6H_2O 40~50 g/L,H_3BO_3 30~45 g/L,十二烷基硫酸钠0.05 g/L,WC微粒(平均粒径400 nm)25~45 g/L,温度30~50°C,电流密度2.0~4.0 A/dm2,时间4 h。研究了WC添加量、阴极电流密度及镀液温度对Ni–WC复合镀层的WC含量和显微硬度的影响。WC添加量为35 g/L,镀液温度为40°C和阴极电流密度为3.0 A/dm^2,所得Ni–WC复合镀层的厚度为103μm,WC质量分数为29.95%,显微硬度为322.4 HV。分别采用Ni–WC复合电极、纯铜电极和纯镍电极为工具电极,对W_7Mo_4Cr_4V_2Co_5高速钢进行电火花加工。结果表明,最佳工艺下制备的Ni–WC复合电极的损耗率分别为纯铜电极和纯镍电极损耗率的72%和62%。

A Ni-WC composite coating was prepared on pure copper substrate by composite electroplating. The bath composition and process conditions are as follows： NiSO4·6H2O 250～300g/L,NiCl2·6H2O 40～50g/L,H3BO3 30～45g/L, sodium dodecyl sulfate 0.05 g/L, WC particles with an average size of 400 nm 25-45 g/L, temperature 30-50 ℃, current density 2.0-4.0 A/dm^2, and time 4 h. The effects of WC dosage, cathodic current density and bath temperature on WC content and microhardness of Ni-WC composite coating were studied. The Ni-WC composite coating obtained with WC 35 g/L at temperature 40 ℃ and cathodic current density 3.0 A/dm^2 has a thickness of 103μm, WC particles content 29.95wt% and microhardness of 322.4 HV. The electrical discharge machining of high-speed steel W7Mo4Cr4VECo5 was conducted using the Ni-WC composite electrode, pure copper and pure nickel as tool electrode, respectively. The results showed that the weight loss of the Ni-WC composite electrode obtained under the optimal process conditions is 72% and 62% that of the pure copper and nickel electrode, respectively.