镀液温度对脉冲电镀镍-铬-钼合金镀层的影响

Effect of Bath Temperature on Pulse Electroplating Ni-Cr-Mo Alloy Coating

采用脉冲电镀法在Q235钢表面制备了Ni-Cr-Mo合金镀层,利用辉光放电光谱仪(GDS)、扫描电子显微镜(SEM)、Tafel曲线和电化学阻抗谱(EIS)考察了镀液温度对镀层元素含量、沉积速率、表面形貌和耐蚀性的影响。结果表明,随镀液温度的升高,镀层镍含量减小,铬含量先增大后减小,钼含量增大;镀层沉积速率稍有增大,镀层表面颗粒尺寸增大,镀层在3.5%NaCl溶液中耐蚀性先增强后减弱;镀液温度为30℃时,镀层最为均匀致密,且具有最大的自腐蚀电位(-0.535V)、最小的腐蚀电流密度(0.123μA·cm^(-2))和最大的电荷转移电阻(2550Ω·cm^2),耐蚀性最好。

Ni-Cr-Mo alloy coatings were prepared on the surface of Q235 steel by pulse electroplating. The effect of bath temperature on coating element content, deposition rate, surface morphology and corrosion resistance were investigated by glow discharge spectroscopy （GDS）, scanning electron microscopy （SEM）, Tafel curve and electrochemical impedance spectroscopy （EIS）. The results show that with increasing bath temperature, Ni content decreases, Cr content increases first and then decreases, Mo content increases; coating deposition rate increases slightly ; the size of particles on coating surface increases ; in 3.5 % NaCl solution, corrosion resistance of coatings strengthens first and then weakens. Coating prepared at 30 ℃ is the most uniform and compact. And it with the biggest corrosion potential （ -0. 535 V）, the smallest corrosion current density （0. 123 μA. cm-2） and the biggest charge transfer resistance （2 550 Ω. cm2） exhibits the best corrosion resistance.