The interfacial reaction in Cr₃C₂/Al₂O₃ composites

This study investigates the effects of sintering atmosphere and temperature on the interfacial properties of Cr₃C₂/Al₂O₃ composites. Thermodynamic considerations and calculations with computer-assisted methods for the equilibrium compositions in the Al–O–Cr–C system were used to simulate the interfacial reaction in Cr₃C₂/Al₂O₃ composite during sintering. The results were in good agreement with the experimental analysis. Cr₃C₂ is more stable during sintering in a system with carbon due to the lower equilibrium oxygen partial pressure. Controlling CO and O₂ gas concentration, Cr₃C₂ first oxidized, decarbonized, and then transformed to Cr₇C₃ before reacting with Al₂O₃. An interfacial reaction between Cr₃C₂ and Al₂O₃ was not observed.