A self-healing environmental barrier coating: TiSi2-doped Y2Si2O7/barium strontium aluminosilicate coating

•Self-healing TiSi2-doped Y2Si2O7/BSAS coatings were developed.•Cracks were enclosed in self-healing coating during corrosion.•Self-healing coatings showed an enhanced durability in water-vapor.•The TiSi2 had an optimal amount (~ 15 wt%) in the self-healing coating.

The TiSi2-doped Y2Si2O7/barium strontium aluminosilicate (BSAS) coating was fabricated on C/SiCs and corroded in a 50%H2O-50%O2 environment at 1250 °C. The C/SiCs coated with TiSi2-doped Y2Si2O7/BSAS showed better durability than that coated with Y2Si2O7/BSAS. Microstructural studies showed that the through-thickness cracks in the TiSi2-doped Y2Si2O7/BSAS coating were filled with the oxidation products of TiSi2, indicating that the TiSi2-doped Y2Si2O7/BSAS coating has self-healing properties. Furthermore, the Y2Si2O7/BSAS coating doped with 15 wt% TiSi2 showed better durability than those doped with 10 wt% and 20 wt% TiSi2, indicating that 15 wt% TiSi2 is the optimum doping amount for Y2Si2O7/BSAS coatings.