Effect Of Nano-SiC On Microstructure And Properties Of Laser Remelted Fe/WC Coating

Laser remelting technology can effectively reduce the porosity of the plasma sprayed cermet coating,improve the microstructure of the coating,and change the bonding interface from mechanical bonding to metallurgical bonding,thereby increasing the microhardness and wear resistance of the coating.However,the differences in the physical and chemical properties of ceramic materials and metals make laser remelting metal ceramic coatings have problems such as microcracks,microporosity,and coating spallation.The various advantages of nanomaterials in terms of performance have led scientists to prepare nanostructured coatings by various methods to improve the problems associated with laser remelted coatings.In this paper,nano-SiC particles are selected as the increasing body.Nano-SiC coating is obtained by pre-setting a layer of nano-SiC powder on the plasma sprayed Fe/WC cermet coating and then laser remelting to obtain a nano-structured coating to to study the improvement mechanism of the nano-SiC coating structure and performance.The finite element analysis software ANSYS was used to numerically simulate the growth of nano-SiC particles under laser irradiation.The influence of laser remelting process parameters on the growth of nano-SiC particles was studied,which provided the theoretical basis for optimizing the process parameters and obtaining nano-structured coatings during the subsequent experiments.Through the analysis of metallography,morphology,distribution of main elements,phase and residual stress,the improvement mechanism of nano-SiC coating structure was studied.The addition of nano-SiC during laser remelting can refine grains,reduce the micro-porosity and micro-cracks on the surface and cross-section of the coating,increase the element diffusion capacity at the interface between the matrix and the coating,increase the metallurgical bonding strength at the bonding interface,and increase the weight of the content of the cemented carbide phase in the molten layer,and reduces the residual stress of the coating.The Microhardness of coating surface and cross-section were tested by microhardness tester and the wear resistance of the coating was tested by friction and wear tester.The addition of nano SiC to the coating performance was studied.The results show that the nano-SiC can increase the microhardness of the surface and cross section of the remelted layer.With the increase of the content of nano-SiC particles,the microhardness also increases accordingly.The addition of nano-SiC during remelting can also improve the wear resistance of the coating and reduce the coefficient of friction and wear weight of the coating under the same conditions.