Prediction and verification analysis of chromium carbide ceramic particle morphology based on first-principles

Chromium carbide reinforced Ni60 composite coating was prepared by laser cladding technology, and its growth morphology and growth mechanism were studied and verified. Based on the first principles, the growth morphology of chromium carbide crystal was predicted in Materials Studio (8.0) software, the interface bonding characteristics of Ni base phase and Cr₃C₂ ceramic phase were simulated and analyzed, the growth mechanism of chromium carbide ceramic phase was studied, and the simulation results were verified by laser cladding experiment. During the experimental verification, a certain amount of C powder and Cr powder are added to Ni60 powder and ball milled as coating powder.The chromium and Nickel carbide composite coating was in-situ generated on the surface of H13 steel by laser cladding technology. The phase and microstructure of the coating were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness of the coating was tested by Vickers hardness tester. The results show that the morphology of chromium carbide formation phase is mainly quadrilateral, hexagonal and other irregular morphology, which is consistent with the morphology prediction results in the simulation results. The average microhardness of the coating reaches 700 HV, which is three times that of the matrix. Quadrilateral chromium carbide is mainly Cr₃C₂, hexagonal chromium carbide is mainly Cr₇C₃, irregular chromium carbide is Cr₇C₃ and Cr₃C₂ eutectic. The chromium carbide enhanced phase prepared in situ is dispersed in the coating, which makes the microhardness of the coating significantly improved compared with the matrix, and the microstructure of the coating is fine and uniform, forming a good metallurgical bonding with the matrix.