Abstract:
The TiB
2-Ni composite powder feedstock was fabricated by agglomeration and sintering method. This powder was used to deposit TiB
2-Ni coating by two thermal spray technologies, atmospheric plasma spray(APS) and high velocity oxygen fuel spray(HVOF). The microstructure, phase constitution, porosity, hardness and fracture toughness of two sprayed TiB
2-Ni coatings were compared and analyzed. The results showed that the HVOF sprayed TiB
2-Ni coating had more compact structure, larger TiB
2 content, higher hardness and better fracture toughness than the APSed coating. The TiB
2 in two coatings had no obviously deboronization and oxidation. However, the TiB
2 in APS process was dissolved in metallic phase to form a large number of brittle Ni
20Ti
3B
6 phases. This dissolution reaction reduced the TiB
2 content in coating and it was the main reason for the lower hardness and worse fracture toughness of APSed TiB
2-Ni coating.