Abstract
In this study, binderless TiC 70 N 30 ceramic composites with varying graphite (TiC 70 N 30 -Gr) reinforcements were fabricated via spark plasma sintering and their effect on densification was assessed. Subsequently, the electrochemical behaviour of TiC 70 N 30 -Gr composites was evaluated in 0.5 mol/L hydrochloric acid (HCl), 0.5 mol/L sulphuric acid (H 2 SO 4 ) and 0.5 mol/L nitric acid (HNO 3 ) solutions using open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The corrosion behaviour of TiC 70 N 30 - based ceramic composites with and without graphite reinforcement exhibited high corrosion resistance in the acidic electrolytes. Composites with 0.5 and 1.0 wt% graphite content showed lower Icorr values of 0.452 mu A and 0.081 mu A in 0.5 mol/L HCL and 0.5 mol/L HNO 3 , respectively, while specimen without graphite addition showed better corrosion resistance in 0.5 mol/L H 2 SO 4 (0.041 mu A). Based on the corrosion results, the corrosion properties of TiC 70 N 30 ceramic composites in HCl and HNO 3 solutions were significantly enhanced upon the incorporation of graphite reinforcements. However, the corrosion test results conducted in H 2 SO 4 solution showed that the addition of graphite had a negligible influence on the corrosion resistance of the titanium carbonitride (TiCN) composites.