氩弧熔敷原位自生WC复合涂层组织及耐磨性

Microstructure and wear resistance of WC composite coating in situ synthesized by argon arc cladding

为提高采煤机中截齿的耐磨性能,利用氩弧熔敷技术,在35CrMnSi钢表面制备WC增强Ni基复合涂层。利用OM、SEM、XRD和EDS分析复合涂层的显微组织,采用显微维氏硬度仪测试复合涂层的显微硬度,并测试涂层在室温磨损条件下的耐磨性能。结果表明:氩弧熔敷涂层组织均匀致密,熔敷涂层与基体呈冶金结合,主要由WC、W2C、γ-Ni、(Fe,Cr)23C6等物相组成;WC颗粒呈弥散分布,颗粒尺寸为1μm;熔敷涂层可以改善基体的表面硬度,最高显微硬度可达12.6 GPa;熔敷涂层在室温冲击磨粒磨损实验条件下,具有优异的耐磨性,磨损机制主要是磨粒磨损,其耐磨性较35CrMnSi基体提高近12倍。

Aimed at improving the wear resistance of cutting teeth of Shearers, this paper introduces Ni-based composite coating reinforced by WC particle, prepared on the surface of 35CrMnSi steel using argon arc cladding technique with the pre-alloyed powder of W, C and Ni60. The paper presents an anal- ysis of the microstructure of the coating by optical microscope, scanning electron microscopy（ SEM）, X- ray diffraction （XRD） and energy-dispersive spectrum （EDS）, an examination of microhardness, and a test of wear resistance at room temperature of the composite coating by means of Microhardness tester and impact abrasion resistance tester respectively. The results suggest that there is the uniform and dense bonding in Argon arc cladding coating, and a metallurgical bonding between cladding coating and the substrate, consisting mainly of the main phases, such as WC,W2C,T - Ni, and （ Fe, Cr） 23 C6 ; that the WC particles, dispersively distributed in the cladded coating is in the range of 1 um ; the composite coat- ing reinforced by WC particle allows the surface hardness of 35CrMnSi steel to be improved; that the highest microhardness could be up to 12.6 GPa; that the composite coating has excellent wear resistance under impact abrasion test conditions and the wear mechanism of coatings results from abrasive wear; and that composite coatings show almost 12 times higher wear resistance than 35CrMnSi steel.