三价铬超声-脉冲电沉积Fe-Ni-Cr/SiC纳米复合镀层

利用超声-脉冲复合电沉积法，在三价铬镀液体系中，添加羧酸盐-尿素配合剂和SiC纳米颗粒，制备了Fe-Ni-Cr/SiC纳米复合镀层.研究了超声-脉冲工艺参数与SiC纳米粒子复合量、Cr含量及镀层厚度的关系；利用稳态极化曲线和循环伏安法分析了超声波对阴极电化学行为的影响.结果表明，超声-脉冲作用均有利于基质金属Fe、Ni和Cr的电沉积，提高了镀层中SiC和Cr的含量以及镀层的厚度.利用扫描电镜、X射线衍射仪和能谱仪对Fe-Ni-Cr/SiC纳米复合镀层的表面形貌、微观结构和组成等进行表征，发现采用该技术可制备厚度为23.56μm，SiC和Cr质量分数分别为4.1%和25.1%的Fe-Ni-Cr/SiC纳米复合镀层.磨损量和腐蚀曲线测试结果表明，SiC含量高的复合镀层，其耐磨性和耐蚀性更好. 

Pulse electrodeposition of nano Fe-Ni-Cr/SiC composite coatings from trivalent chromium baths in ultrasonic fields

Nano Fe-Ni-Cr/SiC composite coatings were prepared by using a pulse electrodeposition method from trivalent chromium baths containing a compound carboxylate-urea system and SiC nanoparticles in ultrasonic fields. The influence of pulse electrodeposition and ultrasonic parameters on the SiC and Cr contents in the composite coatings and the coating thickness was investigated, and the effect of ultrasonicwaves on the electrochemical behavior of the composite coatings was analyzed by steady-state polarization curves and cyclic voltammetry (CV) curves. It is indicated that the SiC and Cr contents in the composite coatings and the coating thickness are significantly increased since both ultrasonic waves and pulse electrodeposition are favorable to the deposition of the matrix metals Fe, Ni and Cr. The surface morphology, phase composition and chemical composition of the composite coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The composite coating with a 23.56μm thickness, 4.1% SiC and 25.1% Cr was obtained by this technique. According to the measurements of weight loss and typical potentiodynamic polarization curves, the properties such as anti-wear and corrosion resistance could be improved by increasing the SiC content in the composite coatings.