激光熔覆纳米WC/Co复合涂层组织与抗裂性能的研究

Microstructure and Anti Cracking Property of Ni/WC-Co Composite Coatings Prepared by Laser Cladding

采用激光熔覆技术在45钢表面制备了基本消除裂纹与孔洞的镍基纳米WC/Co复合涂层,利用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)及原子力显微镜(AFM)分析了涂层的组织结构和相组成,还通过压痕法首次对涂层的断裂韧性进行了表征。结果表明,涂层中物相主要为黑色γ(Fe-N i)基体上分布着W2C、Fe3W3C、(Cr,Fe)23C6的白色碳化物相。在本工艺条件下,当纳米碳化物为网络状+弥散分布的微细颗粒时,镍基纳米WC/Co复合涂层的Kc比常规喷焊镍基WC/Co涂层的Kc提高了约1.2倍,证实了激光熔覆纳米陶瓷复合涂层的抗裂作用。

Nanostructured Ni/WC-Co composite coatings free of cracks and pores have been prepared by laser cladding on 45 carbon steel. The microstructures and phase in the clad coatings were analyzed by XRD, SEM, EDS and AFM analysis methods, other than, the fracture toughness was firstly characterized by the indentation method. The results indicate that the coatings are mainly composed of carbides such as W2C,Fe3W3C and （Cr,Fe）23C6 which dispersedly distribute in the γ（Fe-Ni） substrate. The carbides with network structure among which other fine carbides dispersedly distribute can be obtained under sound process parameters. Under this condition, fracture toughness Kc of nanostructured Ni/WC-Co composite coatings improved about 1.2 times, compared with Ni/WC-Co composite coatings prepared by the traditional spray method,which demonstrates that nanometer phases can serve the anti-cracking function.