STRUCTURAL AND MECHANICAL CHARACTERIZATION OF TI TIC CERMET COATINGS SYNTHESIZED BY LASER MELTING/

Laser surface alloying is an attractive technique for surface treatmen t: by depositing suitable ceramic powder on a titanium substrate, a Ti /TiC cermet coating is obtained by melting a part of the underlying ti tanium. Graphite or titanium carbide powders were pre-deposited on a t itanium foil with the aim to synthesize Ti/TiC cermets. After optimiza tion of the Nd-YAG laser processing parameters, four thicknesses of th e both deposited ceramic powders were used: 10, 20, 30 and 40 mu m. Th e cermet coatings produced have a uniform microstructure and excellent bonding with the titanium substrate, and are free of pores and cracks . Their hardness can reach 520 HV in depth. The volume ratio of TiC ph ase formed and dispersed in the titanium matrix is dependent on the ki nd and thickness of the pre-deposited powder. The results of the micro structural investigations achieved after X-ray diffraction are correla ted with the hardening phenomenon.