大功率电火花熔涂层的金相组织分析

A Metallographical Structural Analysis of High-Power Spark Cementation Coating

钢铁材料表面大功率电火花熔涂强化技术,在我国目前还处于研究试验阶段。本文用金相法,X射线衍射法,特别是电子显微分析技术,对钢材大功率电火花熔涂层进行了由表及里的分析鉴定。涂层表面到内部的金相组织顺次为白亮层、过渡层、热影响区和基材组织。白亮层由碳化物和粘结相组成,碳化物为WC,α—W_2C,W_2(C,O)和M_6C,粘结相是淬火和回火马氏体。过渡层组织是回火马氏体。熔涂层与钢材之间是冶金结合,强轫牢固。

In this paper,the coating technique by means of high-power spark melting cementation is introduced.Thorough and careful examination and identification are conducted of the coating by using the metallographical, X-ray diffractive and,in particular,electron-microscopic analytical me- thods.The metallographical structures of the coating,successively inward from outer surface,are:the bright layer,the transitional layer,the heat- affected zoneand the matrix.The bright layer consists of carbide and adhesive phase.The carbide contains WC,α-W_2C,W_2(C,O)and M_6C, while the adhesive phase is hardened and tempered martensite.The struc- ture of transitional layer is tempered martensite.The combination of the coating with the matrix is metallurgical,which ensures for the material great strength and toughness.