Analysis on microstructure of in-situ synthesis TiC-M₇C₃ ceramic hard phase

TiC-M₇C₃ ceramic hard phases were in situ synthesized using plasma arc surfacing technology.The morphology and distribution of TiC-M₇C₃ hard phases in the surfacing layer was investigated with the X-ray diffraction(XRD),optical microscope(OM),scanning electron microscope(SEM) and spectrum analyzer(EDS).Rockwell hardness tester and wet sand abrasion tester were used to examine the performance of the surfacing layer.The results show that the microstructure of the surfacing layer consists of high-carbon martensite and a large number of ceramic hard phases,for example,TiC and M₇C₃,which disperse in the matrix of surfacing layer.The hardness of the surfacing layer is 66.4 HRC and the weight reduction is 0.086 g.TiC can act as the nuclei of M₇C₃ to improve the nucleation rate of M₇C₃ ceramic hard phases and grain refinement.The Fe-Cr-Ti-C surfacing layer has higher hardness and better wear resistance than Fe-Cr-C alloy due to the combined effect of TiC and M₇C₃ ceramic hard phases.