镀液温度对脉冲电镀镍－铬－钼合金镀层的影响

摘要

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（－0．535 V）、最小的腐蚀电流密度（0．123μA・cm－2）和最大的电荷转移电阻（2550Ω・cm2），耐蚀性最好。%Ni-Cr-Mo alloy coatings were prepared on the surface of Q 235 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 (0.123μA・cm-2 ) and the biggest charge transfer resistance (2 550 Ω・cm2 ) exhibits the best corrosion resistance .