Nb对NiCrBSi氩弧熔覆层显微组织及耐磨性的影响

Effect of Nb on microstructure and wear resistance of NiCBSi coating by argon-arc cladding

为提高低碳钢表面的耐磨性能,以Nb粉和NiCrBSi粉为原料,利用氩弧熔覆技术在Q235钢表面制备耐磨涂层,探讨不同Nb含量对涂层组织及性能的影响。采用扫描电子显微镜、X射线衍射仪、能谱分析仪等分析涂层的物相和显微组织结构,利用显微维氏硬度计和干滑动摩擦磨损试验机测试涂层的显微硬度和耐磨性能。结果表明:熔覆层主要由M23C6、γ-Ni、Nb C和Cr B等物相组成,Nb的加入减少了沉淀相的结构尺寸,碳化物的生长被抑制。随着Nb质量分数的增加,熔覆层的显微硬度逐渐降低。与纯NiCrBSi合金熔覆层对比,Nb质量分数为6%的熔覆层的显微硬度降低了1. 5 GPa,但涂层的磨损失重最少,耐磨性提高了5倍,具有良好的干滑动摩擦磨损性能。

This paper is directed at improving the wear resistance of low-carbon steels.The targeted research involves preparing the wear-resistance coating from Nb powder and NiCrBSi powder on the Q235 steel surface using argon arc cladding technology;investigating the effect of Nb on microstructure and wear resistance;analyzing the microstructure and phase of the wear-resistance coating by scanning electron microscopy,X-ray diffraction and energy dispersion spectrum;and examining microhardness and wear resistance of the wear-resistance coating by means of micro-hardness tester and wear tester.The results indicate that the cladding layer consists mainly of such phases as M 23 C 6,gamma-Ni,NbC,and CrB;the addition of niobium provides a reduction in the structure size of precipitated phase,thus inhibiting the growth of carbides;along with an increase in Nb mass fractions comes a gradual decrease in the microhardness of cladding layer;the cladding layer with Nb mass fraction of 6%exhibits a 1.5 GPa lower microhardness than the pure NiCrBSi coating,but provides the minimum wear weight loss and five times higher wear resistance.The coating demonstrates an excellent dry sliding friction and wear performance.