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用超声-电沉积方式制备Ni-Al_2O_3复合镀层,用扫描电子显微镜(SEM)观察镀层腐蚀前后的表面形貌,用X-射线衍射仪(XRD)分析镀层的相组成,用电化学方法测试镀层在中性及酸性腐蚀介质中的极化曲线(Tafel)及循环伏安曲线(CV),分析超声波对镀层耐蚀性的影响.结果表明,适当的超声波作用使Al_2O_3粒子均匀分散在复合镀层中,使镀层表面平整致密,降低孔隙率,并细化基质金属Ni的晶粒,提高镀层的耐蚀性;在3.5 mass%NaCl溶液中,超声-电沉积复合镀层耐均匀腐蚀及点腐蚀能力都优于单独电沉积复合镀层;在10 mass%H_2SO_4介质中,超声-电沉积复合镀层的维钝电流小,耐蚀性优于单独电沉积复合镀层.
Ni-Al_2O_3 composite coatings were prepared by ultrasonic-electrodeposition. The surface morphology of the coatings was observed by scanning electron microscopy (SEM) before and after the coatings were etched. The phase composition of the coatings was analyzed by X-ray diffraction (XRD) The polarization curves (Tafel) and cyclic voltammetry curves (CV) of neutral and acidic corrosive media were used to analyze the influence of ultrasonic wave on the corrosion resistance of the coatings.The results show that the proper ultrasonic wave can disperse the Al_2O_3 particles uniformly in the composite coatings , So that the surface of the coating is smooth and compact, the porosity is reduced, the grain size of the matrix metal Ni is refined, and the corrosion resistance of the coating is improved. In the 3.5 mass% NaCl solution, the ultrasonic-electrodeposited composite coating has uniform corrosion resistance and pitting corrosion resistance The electrodeposited composite electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrodeposited electrode