脉冲电沉积镍–钨–埃洛石纳米管复合镀层及其耐蚀性

Pulse electrodeposition of nickel–tungsten–halloysite nanotube composite coating and its corrosion resistance

在45钢上脉冲电沉积Ni–W–HNTs复合镀层,基础镀液组成和工艺条件为:NiSO_4·6H_2O 15.8 g/L,Na_2WO_4·2H_2O 46.2 g/L,NaBr 15.5 g/L,柠檬酸三钠147.0 g/L,NH4Cl 26.7 g/L,十二烷基硫酸钠(SDS)0.1 g/L,pH=8.5,温度(70±5)°C,时间60 min。研究了镀液HNTs用量、平均电流密度、脉冲频率和占空比对复合镀层HNTs含量和厚度的影响,得到HNTs的最佳用量为10 g/L,最优脉冲参数为:平均电流密度7 A/dm2,脉冲频率800 Hz,占空比70%。该条件下所得Ni–W–HNTs复合镀层结构均匀、致密,表面平整,厚度为34μm,HNTs质量分数为8.72%,在3.5%NaCl溶液中的耐蚀性优于Ni–W合金镀层。

A Ni-W-HNTs （halloysite nanotubes） composite coating was obtained on 45 steel substrate by pulse electrodeposition. The basic bath composition and process parameters are： NiSO4·6H2O 15.8 g/L, Na2WO4·2H2O 46.2 g/L, NaBr 15.5 g/L, sodium citrate 147.0 g/L, NHaCl 26.7 g/L, sodium dodecyl sulfate （SDS） 0.1 g/L, pH 8.5, temperature （70± 5）℃ and time 60 min. The effects of HNTs content in bath, average current density, pulse frequency and duty cycle on the HNTs content and thickness of composite coating were studied. The optimal dosage of HNTs is 10 g/L, and the optimal pulse parameters are as follows： average current density 7 A/dm2, pulse frequency 800 Hz, and duty cycle 70%. The Ni-W-HNTs composite coating obtained under the given conditions is uniform, compact and smooth, and features a thickness of 34 μm, a HNTs content of 8.72wt%, and a better corrosion resistance than that of Ni-W alloy coating in 3.5% NaCl solution.