Abstract:
The surface ceramic coatings were prepared on Ti-5Al-2.5Sn substrate by tungsten inert-gas arc depositon process. The microstructures and phases were analyzed using the method of SEM and XRD for the cladding coatings of Ti-SiC and Ti-SiC-C systems. Moreover, the changes of Gibbs energy for possible reactions in systems were calculated using thermodynamic analysis. The results shows that the main microstructure are composed with dendritic TiC and needle-shaped or chrysanthemum Ti
5Si
3 in the cladding coating of Ti-SiC system, the reaction mechanism is 8Ti+3SiC→3TiC+Ti
5Si
3. However, in Ti-SiC-C system, there are TiSi
2 and Ti
3SiC
2 hybrid microstructure observed besides TiC. 6Ti+3SiC+C→Ti
3SiC
2+TiSi
2+2TiC is the main reaction mechanism. In addition, the addition of graphite in Ti-SiC system favors to the generation of self-lubricating Ti
3SiC
2 phases, while the brittle Ti
5Si
3 phases are avoided.