碳化钛/钛镍金属间化合物复合涂层相组织研究

A Study on the Phase Structure of Brazed TiC/Ni-Ti Inter-metallic Compound Composite Coatings

利用钛粉、镍粉和胶体石墨,真空条件下通过反应钎涂技术在低碳钢基体上制备了与基体冶金结合的碳化钛/钛镍金属间化合物复合涂层。采用扫描电子显微镜、能谱仪、X射线衍射仪及硬度计,研究了涂层的相组成、组织结构和成分分布。涂层组织由NiTi2、NiTi、TiC和hcp Ti组成,而涂层界面由NiTi和少量的hcp Ti构成,并且TiC主要分布在涂层中层。涂层中的NiTi2、NiTi、TiC是在钎涂过程中原位反应合成的,而且TiC和NiTi的量随碳含量的增加而增加。涂层表面硬度达到85HR15N,但不随TiC和NiTi含量增加而增高。

In this paper,TiC/Ni-Ti inter-metallic compound coatings with a metallurgical bond between a coating and mild steel substrate were prepared by reactive braze coating (RBC) of the mixed titanium, nickel and Carbon powder in vacuum braze furnace. The phases, microstructure and composition distribution of alloy coatings were studied by means of scanning electron microscopy (SEM), energy dispersive spectrum (EDS), X-ray diffraction (XRD) and through hardness testing. The results show that the microstructure of the composite coatings is made up of NiTi2, NiTi, TiC and hcp-Ti phases, and that of the interface is composed by NiTi and hcp-Ti phases, while TiC distributes in the mid-layer of the coatings. The phases of NiTi_2, NiTi and TiC in the coatings were in-situ synthesized during braze coating process.With the raising of the carbon content,the content of NiTi and TiC increases,but the surface hardness of the coatings shifts negligibly, which is high up to 60HRC.