Slurry-based coating system repair

1. A method comprising:

applying a wet bond coat slurry to a damaged area of a coating system on a metal substrate, wherein the bond coat slurry comprises a liquid binder, at least one of glass particles or glass-ceramic particles, and ceramic oxide particles;

depositing a plurality of fibers onto the wet bond coat slurry at least one of during or after the wet bond coat slurry is applied to the damaged area, wherein the plurality of fibers includes at least one of metallic fibers or ceramic fibers;

applying a ceramic composite slurry on the bond coat to form a ceramic composite layer, wherein, during the application of the ceramic composite slurry on the bond coat, the bond coat is wet or at least partially dried, wherein the wet or at least partially dried bond coat includes a plurality of partially exposed fibers, wherein, following the application of the ceramic composite slurry, a first portion of individual fibers of the plurality of fibers are embedded in the wet or at least partially dried bond coat and a second portion of the individual fibers of the plurality of fibers extend into the layer of the ceramic composite slurry; and

heating the wet or at least partially dried bond coat and the ceramic composite layer to form a repaired portion of the coating system on the metal substrate, wherein heating the bond coat melts at least a portion of the at least one of the glass particles or the glass-ceramic particles to form a fully amorphous glass phase or a mixture of amorphous and crystalline glass phases which bond with the metal substrate.

2. The method of claim 1 , wherein the liquid binder of the bond coat slurry comprises at least one of an ethyl polysilicate binder or other silicon alkoxide binder.

3. The method of claim 2 , wherein the ceramic composite slurry applied to the at least partially dried bond coat comprises the at least one of the ethyl polysilicate binder or other silicon alkoxide binder.

4. The method of claim 1 , wherein the at least one of glass particles or glass-ceramic particles comprise glass-ceramic powder.

5. The method of claim 4 , wherein the glass-ceramic powder comprises at least one of Ba—Ba—Si—Al—Mg—B, or Ba—Sr—Ca—Si—Al—Mg—B.

6. The method of claim 1 , wherein the bond coat slurry comprises a catalyst for a sol-gel reaction of the bond coat.

7. The method of claim 1 , wherein the ceramic oxide particles comprise at least one of MgO, Al 2 O 3 , or MgAl 2 O 4 particles.

8. The method of claim 1 , wherein the metal substrate comprises the metal substrate of an in-service component.

9. The method of claim 8 , wherein the in-service component comprises an exhaust component of a gas turbine engine mounted to an aircraft.

10. The method of claim 9 , wherein heating the dried bond coat and the ceramic composite slurry layer to form a repaired portion of the thermal barrier coating system on the metal substrate comprises heating the dried bond coat and the ceramic composite slurry layer via exhaust gas of the gas turbine engine.

11. The method of claim 1 , wherein at least a portion of the ceramic oxide particles remain unreacted following the heating of the dried bond coat and the ceramic composite slurry layer.

12. The method of claim 1 , wherein the metal substrate comprises a nickel superalloy, a cobalt superalloy, or a titanium alloy.

13. The method of claim 1 , further comprising leaving the in-service component as part of an assembly of which the in-service component is a part throughout the method of claim 1 .