抄録
High-efficiency gas turbine blades, which must withstand increasingly severe temperature and steam environments, are effectively protected by thermal/environmental barrier coatings. However, their inherent brittleness often leads to crack formation, thereby compromising their function. To address this issue, this study proposed a self-healing approach. Yb2Si2O7 matrix dispersed with SiC particles or whiskers exhibit crack healing and strength recovery above 750℃. At elevated temperatures, the flexural strength increases beyond its initial value due to the reinforcing effect of compressive stresses. Under steam exposure, Yb2Si2O7 partially decomposes into Yb2SiO5 , which reacts with SiO2 to reform Yb2Si2O7 that removes residual SiO2 and maintains a single-phase structure, although cracking may occur at high temperature in a steam atmosphere. Alternatively, Y2Ti2O7 provides a regeneration pathway by converting to TiN at the surface in a N2 atmosphere. Upon re-oxidation, TiN transforms into TiO2 , whose volumetric expansion effectively closes surface cracks. These findings underscore the potential of advanced ceramic coating that integrates efficient crack healing with long-term stability under the harsh conditions of turbine operation.
