Precipitation induced crack healing in a Ti2SnC ceramic in vacuum

Self-healing ceramics are able to heal cracks through an oxidative healing mechanism at high temperature in oxidizing environments with the recovery of original performance and functionality. However, the oxidation induced repair may be impossible when the ceramics are used in vacuum or inert atmospheres with low oxygen partial pressures. So far little work has been done on crack healing in vacuum or inert atmospheres. Here we report on the crack healing of a Ti2SnC ceramic in vacuum by a precipitation induced repair mechanism. Cracks induced by thermal shock in Ti2SnC are completely filled by only metallic Sn at temperatures above 800 °C for only 1 h in vacuum. The electrical conductivity of healed materials is fully recovered, and it even exceeds the initial conductivity. This work might bring a new wave of research on crack healing behavior of ceramics in low oxygen partial pressure environments.