复合电刷镀镍–钨–钴–纳米碳化硅及其性能

Electro-brush plating of nickel–tungsten–cobalt–nano silicon carbide composite coating and its properties

采用电刷镀工艺在45钢表面制备了Ni—W—Con-SiC（纳米碳化硅）复合镀层，镀液组成和工艺条件为：NiSO4·7H2O393g／L，Na2WO4·2H2O23g／L，H38O331g／L，柠檬酸42g／L，Na2SO46．5g／L，CoSO4·7H2O3g／L，NaF5g/L，n-SiC0～30g／L，温度25～45℃，DH1．4～2．4，电压5～7V，镀笔速率0．8m／s，时间25min。以Ni-w-Co合金镀层的外观为指标，筛选得到较适合的复合电刷镀电压为6V。研究了镀液F／-SiC含量对镀层的组织结构、显微硬度和摩擦磨损性能的影响。结果表明，镀液中n-SiC含量为15～25g／L时，可以获得颗粒均匀分布、无微裂纹的Ni—w-Co-n-SiC复合镀层。随镀液中F／-SiC含量增大，复合镀层的晶化程度、Ni固溶度和显微硬度均提高，耐磨性改善，但摩擦因数的变化不大。

A Ni-W-Co-n-SiC （nano silicon carbide） composite coating was prepared on the surface of 45 steel by electro-brush plating. The bath composition and process conditions are as follows： NiSOa＇7H20 393 g/L, Na2WOa.2H20 23 g/L, H3BO3 31 g/L, citric acid 42 g/L, Na2SO4 6.5 g/L, COSO4.7H2O 3 g/L, NaF 5 g/L, n-SiC 0-30 g/L, temperature 25-45 ℃, pH 1.4-2.4, voltage 5-7 V, moving rate of plating pen 0.8 m/s and time 25 min. The suitable voltage for composite electro-brush plating was determined as 6 V based on the evaluation of appearance using a Ni-W-Co alloy coating as the standard. The effect of n-SiC content in bath on the structure, microhardness and friction-wear performance of the nanocomposite coating was studied. The results showed that a crack-free Ni-W-Co-n-SiC composite coating with uniformly distributed particles can be obtained from the bath containing 15-25 g/L SiC nanoparticles. With increasing n-SiC content in bath, the crystallization degree, solid solubility of Ni, as well as microhardness and wear resistance of composite coating are increased, while the friction coefficient of the composite coating surface is changed little.