中文摘要：

应用直流、脉冲电沉积技术分别制备Ni-Cr纳米复合镀层，研究了电沉积方式对其性能的影响。结果表明：随着镀液中Cr浓度的增大，用两种电沉积方式制备的镀层中Cr含量均随着镀液浓度的增加而增加，但是在镀液中Cr浓度相同的条件下脉冲纳米复合镀层的Cr含量比直流纳米复合镀层的高。在900℃氧化24h后，脉冲纳米镀层的抛物线速度常数低于直流镀层的2．85倍，在含Cl离子和酸性水溶液中其耐蚀性能均优于直流方式制备的纳米复合镀层。脉冲镀层的显微硬度比直流镀层的高2倍。脉冲电沉积能降低镀层表面的浓差极化，控制关断时间，使晶核的形成几率增大，晶核数量增多，从而制备出平整、致密、细化的复合镀层。

英文摘要：

Ni-Cr nanocomposite coatings were prepared by D. C. and pulsed D.C. electroplating technique, respectively, and the contents of Cr in the nanocomposite film was investigated. The results show that the codeposition of Cr nanoparticles in the nanocomposite coating by D.C. electroplating firstly increased with the Cr concentration in electrolyte bath, but the contents of Cr in the film prepared by pulsed D.C. electroplating are higher than those of the D.C. electroplating for the same concentration Cr in the electrolyte bath. The parabolic rate constant for the pulse nanocomposite coating is 2.85 times that of D.C. electroplating films after oxidation at 900℃ for 24 h, and the corrosion resistance of the pulse nanocomposite coatings is better than that of the D.C. electrodeposited films in CI ion solution and acid solution. Meanwhile, the microhardness of the pulse nanomcoposite coatings is 2 times that of the D.C. electroplated films. The pulse electrodeposition can reduce the concentration distinction polarization on the surface of the pulse nanocomposite coatings, controll the shut off time, and increase the possibility of nuclei formation, so the amounts of grain nuclei increase and the perfect nanocomposite coatings with finer grains and more compact structure can be obtained.