Oxidation behaviour of Si3N4/Y2O3 system ceramics and effect of crack-healing treatment on oxidation

The main results obtained are as follows: (1) when Y2O3 was used as an additive, Si3N4 ceramics exhibited extensive oxidation at low temperatures (700-1000 °C). (2) Si3N4/Y2O3 ceramics with 3-wt% Al2O3 added as an additive showed no extensive oxidation. (3) Crack-healing, as a pre-oxidation treatment, is useful for increasing the oxidation-resistance of ceramics at 1000 °C and for increasing the strength.