Ni对TiC-Ni超音速火焰喷涂层组织和耐磨性的影响

Ni对Ti-Ni-C体系SHS反应中的热力学与动力学均有重要影响,Ni在超音速火焰喷涂合成中的作用尚不明确.利用超音速火焰喷涂合成技术制备了3种不同Ni含量的TiC-Ni金属陶瓷涂层,并对涂层进行了组织和性能研究.结果表明,Ni在喷涂过程中起到了吸收反应热、减缓喷涂合成过程中粉末组分的氧化、并在涂层中黏结相金属的作用.原料中的Ni含量对涂层的组织和性能影响较大,Ni含量低涂层中含有大量氧化物,且组织疏松、滑动磨损性能差;随着Ni含量升高到40%时,涂层的氧化物含量降低,滑动磨损性能增强; Ni含量过高,涂层中Ni片层增多,硬质相间距加大,涂层的耐磨损性能有所降低.

Influence of Ni on the Microstructure and Wear Resistance of TiC-Ni Coatings Prepared by Reactive High Velocity Oxy Fuel Flame Spraying

Nickel plays an important role to the thermodynamics and reaction dynamics in self-propagation high temperature synthesis reactions,but little is currently available on the action of nickel in high velocity oxy fuel flame spraying (HVOF).Thus the influence of Ni on the microstructure and wear resistance of HVOF TiC-Ni cermet coatings with varies Ni content was investigated.Results showed that Ni was able to absorb reaction heat,retard the oxidation of the granulated ingredients,and increase the interfacial bonding strength of the target cermet coatings.Moreover,the microstructures and wear resistance of the target cermet coatings were highly dependent on the Ni content in the granulated raw materials.Namely,the cermet coating prepared from the granulated raw materials of a low Ni content was composed of a large amount of oxides and had incompact microstructure and poor wear resistance.Contrary to the above,the cermet coating prepared from the granulated raw material of an increased Ni content as much as 40% contained less amount of oxides and increased wear resistance.However,the cermet coating prepared from the granulated raw material of an extremely high content of Ni had a high content of flake-like Ni and increased space among the hard phases,which corresponded to a decreased wear resistance as well.