三价铬超声-脉冲电沉积Ni-Cr/SiC纳米复合镀层

Pulse Electrodeposition of Nano Ni-Cr/SiC Composite Coatings from Trivalent Chromium Baths in Ultrasonic Field

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Ni-Cr/SiC纳米复合镀层。研究了超声-脉冲工艺参数对SiC纳米粒子复合量、铬含量以及镀层厚度的影响;利用电化学法分析了超声波对基质金属电沉积行为的影响。结果表明,超声-脉冲作用均有利于基质金属铬-镍的电沉积,从而提高镀层厚度及SiC与Cr的含量。利用SEM、XRD、和EDS分别对Ni-Cr/SiC纳米复合镀层的表面形貌、微观结构和相组成等进行表征。结果表明,采用该技术可制备厚度为21.2μm、SiC和Cr含量分别为3.8%和24.68%(质量分数)的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。

The nano Ni-Cr/SiC composite coatings were prepared using a pulse electrodeposition method from trivalent chromium baths containing compound carboxylate-urea system and nano SiC in ultrasonic field. The effects of the pulse electrodeposition and ultrasonic parameters on the SiC and Cr contents and thickness of the composite coatings were investigated, and the electrochemical behavior of the electrodeposition nano Ni-Cr/SiC coatings in ultrasonic field was measured by electrochemical methods. Results indicate that the SiC and Cr contents and thickness of the Ni-Cr/SiC composite coatings could be significantly improved by the increasing of the electrodeposition rate of matrix Ni-Cr alloy using this technique. The surface morphology, phase composition and chemical composition of the as-posited coating was characterized by the scanning electron micrographs （SEM）, X-ray diffraction and energy dispersive spectrum （EDS） analysis, respectively. The result show the Ni-Cr/SiC composite coatings of 21.2μm thickness with 3.8 wt% SiC and 24.68 wt% Cr can be obtained in this study. In addition, according to the results of the measurement of mass loss and the typical potentiodynamic polarization curves, the properties such as anti-wear and corrosion resistance could be improved by the increasing of SiC content in the Ni-Cr/SiC composite coatings.