Ni含量对TiC-TiB_2-Ni涂层组织与性能的影响

Effect of nickel content on microstructure and properties of TiC-TiB_2-Ni coatings

利用超音速火焰喷涂技术在45钢基体表面制备了4种不同Ni含量的TiC-TiB2-Ni金属陶瓷涂层，并对涂层的组织和相关性能进行了研究。结果表明，Ti-B4C-Ni体系在喷涂过程中发生剧烈的放热反应，可以成功合成TiC-TiB2-Ni金属陶瓷涂层，涂层的主要组成相为TiC、TiB：和Ni，另外，还含有一定量的Ti（C，N）、TiO2、TiO3，和NiO。随着金属Ni含量的增加，涂层组织的均匀性逐渐增强，显微硬度逐渐减小，结合强度和耐滑动磨损性能呈先升高后降低的变化趋势。Ni含量为30％～40％时，涂层的结合强度和耐滑动磨损性能较好，涂层的滑动磨损失效形式主要为犁削和脆性剥落。

Four kinds of TiC-TiB2-Ni coatings were prepared on the surface of 45 steel substrate by ultrasonic flame spraying technology. The effect of nickel content on microstructure and properties of the TiC-TiB2-Ni coating was re- searched. The results show that the TiC-TiB2-Ni ceramics coating can be achieved with the exquisite exothermic reaction of Ti-B4C-Ni system during spraying. The major phases of the coating are TiC ,TiB2 and Ni,and the secondary phase are Ti （ C, N）, TiO2,TiO3 and NiO. With increasing the Ni content, the microstructure homogeneity of the coating increases and its micro-hardness decreases gradually. However the bonding strength and wear resistance present the trend of first increasing and then decreasing. The bonding strength and wear resistance reaches optimum value with Ni content of 30% -40%. The wear failure mechanism of the coating is mainly ploughing and brittle spalling.