Strength recovery and degradation behaviors in Al2O3-based self-healing ceramics with vanadium carbide additives

Ceramic bearings possess superior thermal and mechanical properties but are prone to crack formation and lubricant degradation at high temperatures, driving the development of self-healing ceramics to improve their reliability and lifespan. This study investigates the high-temperature self-healing behavior of surface cracks in Al 2 O 3 -containing vanadium carbide (VC) particles and Al 2 O 3 pre-incorporated with both SiC and VC particles as healing agents. Bending tests show that the required healing time for reaching the strength of 500 MPa in Al 2 O 3 containing both VC and SiC achieves approximately 1/6000 times shorter than that in Al 2 O 3 -SiC composites without VC addition and significantly shorter than that of VC-added Al 2 O 3 . Excessive internal oxidation of pre-incorporated submicron- to micron-sized VC induces pore formation, reducing strength and hindering full-strength recovery. Formation of a SiO 2 protective layer against SiC oxidation mitigates pore formation. These findings provide a basis for designing ceramics capable of rapid, low-temperature self-healing without pore generation.