电沉积非晶态Ni-W-B/ZrO2复合镀层及其结构与性能

在含有二氧化锆的Ni-W-B电解液中，电沉积获得Ni-W-B/ZrO2复合镀层.用差示扫描量热分析(DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学技术较系统地研究了Ni-W-B/ZrO2复合镀层的电沉积、热处理过程，以及镀层的结构、表面形貌、显微硬度和耐腐蚀性能.结果表明, 复合镀层的质量组成为Ni 47.5％、W 40.9％、B 0.9％和ZrO2 10.7％. DSC和XRD结果清楚说明, 二氧化锆对基质Ni-W-B镀层的结构有明显影响, 使得复合镀层的非晶态结构特征更加明显 .复合镀层比Ni-W-B合金有更高的显微硬度, 呈现团粒状结构, 晶块之间不存在裂纹但晶界清晰可辨; 二氧化锆粒子分散于Ni-W-B基质镀层中. 400 ℃、1 h热处理后, Ni-W-B基质镀层中W向镀层表面偏析, 镀层呈现固溶体晶态结构特征, 表面形貌特征基本不变, 复合镀层的显微硬度进一步提高, 抗腐蚀性能增强, 但镀层表层中的二氧化锆粒子大量脱落.

Electrodeposition,Structure and Properties of an Amorphous Ni-W-B/ZrO2 Composite Coating

Ni-W-B/ZrO2 composite coating was electrodeposited from the Ni-W-B electrolyte solution containing zirconia particles. The electrodeposition, heat treatment, structure, surface morphology, microhardness, and corrosion resistance of the composite coating were studied by means of differential scanning calorimeter (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical techniques. The results showed that the mass composition of the obtained Ni-W-B/ZrO2 composite coating was Ni 47.5％,W 40.9％, B 0.9％ and ZrO2 10.7％. DSC combined with XRD results illustrated that zirconia took a remarkable influence on the structure of Ni-W-B matrix, leading the composite coating to a more obvious amorphous characteristics. The composite coating presented in higher microhardness compared to Ni-W-B alloy, granular structure with grain boundaries and crack-free. Zirconia particles were dispersed in the Ni-W-B matrix. After heat treatment at 400 ℃ for 1 h, surface morphology of the coating was kept almost no changes. The structure of the matrix was transferred to a crystal of Ni-W solid solution, and W was segregated to the surface of the deposit. The microhardness and corrosion resistance were enhanced, whereas most of zirconia particles were gotten rid of from the surface layer.