A water-quenching technique was used to evaluate the thermal-shock strength behavior of silicon nitride (Si3N4) ceramics in an air atmosphere. When the tensile surface was shielded from air during the heating and soaking process, the quenched specimens showed a gradual decrease in strength at temperatures above 600degreesC. However, the specimens with the air-exposed surface exhibited a similar to16% and similar to29% increase in strength after quenching from 800degrees and 1000degreesC, respectively. This is because of the occurrence of surface oxidation, which may cause the healing of surface cracks and the generation of surface compressive stresses. As a result, some preoxidation of Si3N4 components before exposure to a thermal-shock environment is recommended in practical applications.