电沉积晶态钨基合金镀层组织及磨损性能

摘要

Electroplating Ni-W coatings have been prepared on medium carbon steel substrate using nickel sulphate and sodium tungstate as precursors. The elemental composition, microstructures, phase composition and performance of the coatings were analyzed by SEM, EDS, AFM, XRD, microhardness tester and wear tester. The surface morphologies after wear were observed and the wear mechanism was analyzed. The results show that Ni-W alloy coatings are not found to have obvious flaws and and have a good bond with the matrix. The crystalline Ni-W coating is composed of Ni-based solid solution and the coatings before and after heat treatment are crystalline structure. The microhardness of the coatings increases with increasing heat treatment temperature, reaching its maximum value (1 100 HV0.3) for heat treatment at 500 ℃, and then decreases for heat treatment at higher temperatures. Due to the low surface roughness of the coating with heat treatment, high microhardness, the crystalline Ni-W coating has strong wear resistance.%以硫酸镍和钨酸钠为主盐，采用电沉积方法在中碳钢上制备Ni-W合金镀层，通过SEM、EDS、AFM和XRD 等分析镀层组织结构、元素分布和物相组成。利用显微硬度计及磨损试验测试镀层的力学性能，观察试样磨损形貌，分析磨损机理。结果表明：制备的Ni-W镀层未见明显缺陷，镀层与基体结合良好；Ni-W镀层为Ni 基固溶体，热处理前后的镀层均为晶态结构；镀层显微硬度随热处理温度升高而增大，于500℃达最大值，为1010 HV0.3，而后降低；由于热处理后镀层表面粗糙度小、显微硬度高、耐磨性能增强，Ni-W 镀层具有较强的抗磨能力。