Microstructure and property of reactive high velocity oxygen fuel spraying TiC-TiB2-Ni coatings

Key words:  reactive thermal spray  high velocity oxygen fuel spray  TiC-TiB2-Ni  composite eoatings} friction and wear behavior

Abstract:

Three kinds of TiC-TiB2-Ni coatings were sprayed on the steel substrate with reactive high velocity oxygen fuel (HVOF) spraying technique and Ti-B4C-C-Ni reactive system. Microstructure and properties of TiC-TiB2-Ni coatings were researched. The results reveal that TiC-TiB2-Ni ceramic coatings can be successfully prepared with Ti-B4C-C-Ni reactive system. The reaction of Ti-B4C system is more likely to occur than that of Ti-G system. TiC-TiB2-Ni coatings are composed of the major phases of TIC, TiB2，Ni, some phases of Ti(C,N) , Ti02，Ti203 and NiO. Their microhardness, binding strength and wear resistance decrease with TiB2 content decreasing. The introduction of TiB2 ceramic phase can significantly improve coatings' mechanical properties. The coating sprayed with Ti-B4C-Ni reactive system has the highest binding strength, microhardness and the best wear resistance in all. Furthermore, its wear mechanism is characterized by spalling and ploughing.