TIG熔覆原位自生TiC-TiB2/Fe复合涂层

利用氩弧作为热源，以G302铁基合金粉、FeTi70粉和B₄C粉作为原料粉末，在Q235表面原位生成TiC-TiB₂增强的铁基复合涂层. 采用一系列的分析测试方法对涂层进行了表征，结果表明，氩弧熔覆过程冶金反应充分，熔覆层中生成了TiC，TiB₂和M₇C₃等硬质增强相；熔覆层组织呈现出由母材界面到熔覆层表面硬质相逐渐增多的梯度分布特征. 增加FeTi70和B₄C粉末比例提高了熔覆层硬度，质量比为G302:FeTi70:B₄C=6:3:1时，试样最大硬度达到976 HV0.1，是母材硬度的5倍左右. 在与GCr15钢对磨时，熔覆试样磨损量仅为Q235钢的1/30左右，熔覆层磨损表面基本无塑性变形痕迹，涂层中坚硬的TiC，TiB₂陶瓷相起到阻磨作用.

Microstructure and properties of in situ synthesized TiC-TiB2/Fe composite coatings by TIG cladding

In this paper, in situ generated TiC-TiB₂ reinforced Fe based composite coatings were prepared on the surface of Q235 steel using tungsten inert gas (TIG) cladding from G302 alloy powder, FeTi70 powder and B₄C powder. The coatings were characterized by a series of testing methods. The results showed that the metallurgical reaction fully finished during the TIG cladding. The TiC, TiB₂ and M₇C₃ reinforced phase generated in cladding layer. The microstructure presented gradient distribution characteristics with the hard phases increasing gradually from the interface between the parent metal and the cladding layer to the surface of cladding layer. The hardness of cladding layer increased with increasing the proportion of FeTi70 and B₄C powders. When the mass ratio of G302: FeTi70: B₄C =6:3:1, the maximum hardness of sample was 976 HV0.1, which was about 5 times of the parent metal hardness. The coatings showed great wear resistance when sliding with the GCr15 steel. The wear loss of the coatings was about 1/30 of the Q235 steel, and no plastic deformation traces were found on the wear surface of coatings. The hard ceramics phases in the coating, such as TiC and TiB₂, played a wear resistance role.