钼对铁基合金等离子熔覆层组织及耐磨性能的影响

Effect of Molybdenum on Microstructure and Wear Resistance of Iron-based Alloy Coating Clad by Plasma Transferred Arc Process

应用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)和磨粒磨损试验,研究了质量分数为4%的钼对等离子熔覆铁基合金涂层组织结构和耐磨性能的影响。结果表明,未加钼的铁基合金熔覆层主要由面心立方结构的-γ(N i,Fe)固溶体、正交结构的(Cr,Fe)7C3和四方结构(Cr,Fe)2B等物相构成,组织为粗大的亚共晶。4%Mo的加入,不但使熔覆层中出现了立方结构的M23C6和正交结构的Mo2C,而且增加了共晶化合物相的相对含量。添加4%Mo的熔覆层呈伪共晶特征,组织得到显著细化。4%Mo的加入所引起的新相析出和组织细化是铁基熔覆层耐磨性提高的原因。

The effect of addition of 4% Mo on the microstructure and wear resistance of iron-based alloy coating clad by a plasma transferred arc process was investigated by means of OM, SEM, XRD, TEM and abrasive particle wear testing. The results show that the clad molybdenum-free iron-based alloy coating will consist of γ- （ Ni, Fe） solid solution with a face-centered cubic lattice, （Cr, Fe）7C3 with a rhombic crystal structure and （Cr, Fe）2B with a tetragonal crystal structure ,with a coarse hypoetectic structure being obtained. The addition of 4% Mo not only leads to the existence of M23 C6 with a cubic structure and Mo2 C with a orthorthombic structure in clad coating but results in the increase in relative content of eutectic compound. The clad coating with 4% Mo is characteristic of pseudoeutectic structure and its microstructure in obviously refined. The precipitation of new phases and microstructure refinement is attributed to the increase in wear resistance for the clad iron-based alloy coating with 4% Mo.