This application relates to a method of repairing a coating on a component having small cooling air holes.
Gas turbine engines are known, and typically include a compressor delivering air into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors, driving them to rotate. The turbine rotors typically include rotor drums carrying a plurality of blades. The blades are subjected to a great deal of heat, and thus air-cooling techniques have been developed for the turbine blades. In addition, there are typically static vanes positioned intermediate rows of the blades, and the static vanes are also provided with air-cooling techniques.
Other locations within a gas turbine engine also experience challenges from heat. As an example, structure in the combustion section may require air-cooling. In addition, components downstream of the turbine sections may also experience very high temperatures, and may be provided with air-cooling.
One standard air-cooling technique is a provision of a plurality of very small holes to direct cooling air from an internal cavity in the component to the outer surface of the component. Other ways of providing air to the holes would include supplying air from a plenum, or a pressurized air stream.
In addition, the components are typically provided with various coatings to assist in surviving the extreme challenges of the turbine environment. One such coating is a thermal barrier coating. The thermal barrier coatings have sometimes become distressed, such as experiencing spallation or liberation. The components are then typically recoated.