Oxidation/Carburization Behavior of TiC-Ti Composites and Improved Wear Resistance through Surface Modification

This study has developed a surface modified titanium carbide (TiC)-titanium (Ti) composite for application in dry press working. This material was synthesized through mechanical alloying using Ti and graphite powder, followed by spark plasma sintering, and subsequently surface -modified via oxidation/carburization treatment. The oxidation/carburization behavior was investigated to determine the treatment conditions that formed a hard coating layer, and its wear resistance was evaluated. The activation energy for the isothermal oxidation of this composite material was 271 kJ/mol, with the rate primarily determined by the O and Ti diffusion in titanium dioxide (TiO2). In contrast, the activation energy for the growth of the carburized layer growth was 261 kJ/mol, with the rate determined by the carbon diffusion in TiC. The oxide film of the TiC-Ti composite material, oxidized by holding at 1073 K for 300 s, exhibited porous rutile TiO2 with a thickness of approximately 1.7 mu m and hardness of 11 GPa. The carburized layer of the TiC-Ti composite material, carburized at 1073 K and held for 2400 s, had a thickness of approximately 3 mu m and hardness of 20 GPa. During a wear test utilizing a stainless -steel pin as the mating material, stainless steel adhered to the surface of the unmodified sample. The oxidized sample experienced wear due to the peeling of the oxide film. However, the carbonized sample neither adhered to nor wore the mating material, suggesting that the carbonization treatment helps to improve the wear characteristics. This study offers valuable insights into the fabrication of TiC-based cermets as mold materials for realizing dry press working.