Ni包B4C陶瓷颗粒增强Ni基合金激光熔覆层的性能

Using a 3 kW high-power semiconductor laser, Ni-based Ni-coated B4C composite ceramic coatings with different contents were prepared on a 304 steel substrate. The microstructure, phase, hardness and wear resistance of the cladding layer were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), a microhardness tester and a friction and wear testing machine respectively. The results show that the cladding layer is mainly composed of phases such as γ - Ni solid solution, B4C, Fe3B, Ni4B3, Cr5B3, CrB, Cr3C2, Cr2Ni3, etc.; the grains at the bottom of the cladding layer grow in the form of fine dendrites approximately perpendicular to the substrate interface, there are columnar crystals and dendrites in a certain direction in the middle, and the upper part is disordered equiaxed dendrites; when the content of Ni-coated B4C is 40%, the structure of the cladding layer is uniform and dense, the grains are fine, it is metallurgically bonded with the substrate, the microhardness is up to 1261 HV, which is 5.7 times that of the substrate, and the wear resistance is also relatively good, which is 12 times that of the substrate.

利用3 kW高功率半导体激光器,在304钢基体上制备不同含量Ni基Ni包B4C复合陶瓷涂层,分别用扫描电镜（SEM）、X射线衍射（XRD）、显微硬度计及摩擦磨损试验机对熔覆层的显微组织、物相、硬度及耐磨性进行研究。结果表明:熔覆层主要由γ-Ni固溶体、B4C、Fe3B、Ni4B3、Cr5B3、CrB、Cr3C2、Cr2Ni3等物相组成;熔覆层底部晶粒以近似垂直于基体界面的细小树枝晶的形态生长的,中部以一定方向柱状晶和树枝晶存在,上部是杂乱无章的等轴枝晶;Ni包B4C含量为40%时,熔覆层组织均匀致密、晶粒细小,与基体冶金结合,显微硬度最高1261 HV,是基体的5.7倍,耐磨性也相对较好,是基体的12倍