中文摘要：

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、扫描电镜、Tafel曲线和电化学阻抗谱考察了尿素含量对镀层元素含量、沉积速率、表面形貌和耐蚀性的影响。结果表明,随尿素含量的增大,镀层镍含量先增大后缓慢减小,铬含量先增大后减小、钼含量先减小后增大;镀层沉积速率先增大后减小;镀层表面颗粒尺寸减小;镀层在3.5%NaCl溶液中耐蚀性先增强后减弱。尿素含量为60 g·L^-1时制备的镀层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（2 550Ω·cm^2）,耐蚀性最好。

英文摘要：

Ni-Cr-Mo alloy coatings were prepared on the surface of Q235 steel by pulse electroplating. The effect of urea content on coating element content, deposition rate, surface morphology and corrosion resistance was investigated by glow discharge spectroscopy（GDS）, scanning electron microscopy（SEM）, Tafel curve and electrochemical impedance spectroscopy（EIS）. The results show that, with the increase of urea content, Ni content increases and then decreases slightly, Cr content increases and then decreases, Mo content decreases and then increases; coating deposition rate increases and then decreases; the size of particles in coating surface decreases; in 3.5% NaCl solution, the corrosion resistance of the coatings strengthens first and then weakens. The coating prepared in 60 g·L^-1 urea bath has the biggest corrosion potential（-0.535V）, the smallest corrosion current density（0.123 μA·cm^-2） and the biggest charge transfer resistance（2 550 Ω·cm^2）, and exhibits the best corrosion resistance.