摘要:
A method of repairing a thermal barrier coating on a component designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method more particularly involves repairing a thermal barrier coating on a component that has suffered localized spallation of the thermal barrier coating. After cleaning the surface area of the component exposed by the localized spallation, a ceramic paste comprising a ceramic powder in a binder is applied to the surface area of the component. The binder is then reacted to yield a ceramic-containing repair coating that covers the surface area of the component and comprises the ceramic powder in a matrix of a material formed when the binder was reacted. The binder is preferably a ceramic precursor material that can be converted immediately to a ceramic or allowed to thermally decompose over time to form a ceramic, such that the repair coating has a ceramic matrix. The repair method can be performed while the component remains installed, e.g., in a gas turbine engine. Immediately after the reaction step, the gas turbine engine can resume operation during which the binder is further reacted/converted and the strength of the repair coating increases.
摘要:
A method of repairing a thermal barrier coating (16) on a component (10) designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method more particularly involves repairing a thermal barrier coating (16) on a component (10) that has suffered localized spallation (20) of the thermal barrier coating (16). After cleaning the surface area (22) of the component (10) exposed by the localized spallation (20), a ceramic paste (24) comprising a ceramic powder in a binder is applied to the surface area (22) of the component (10). The binder is then reacted to yield a ceramic-containing repair coating (26) that covers the surface area of the component and comprises the ceramic powder in a matrix of a material formed when the binder was reacted. The binder is preferably a ceramic precursor material that can be converted immediately to a ceramic or allowed to thermally decompose over time to form a ceramic, such that the repair coating (26) has a ceramic matrix. The repair method can be performed while the component (10) remains installed, e.g., in a gas turbine engine. Immediately after the reaction step, the gas turbine engine can resume operation during which the binder is further reacted/converted and the strength of the repair coating increases.
摘要:
A protective coating and coating method for protecting a thermal barrier coating (TBC) on a component, such as a component of a gas turbine engine. The protective coating comprises alumina particles in a silica-containing matrix, and may be substantially homogeneous or formed of multiple layers having different compositions. The composition and relative amounts of alumina and matrix material in the protective coating enable the coating to react with molten compounds containing calcia, magnesia, alumina and/or silica (CMAS), forming a compound with a melting temperature that is significantly higher than CMAS. As such, infiltration of molten CMAS into the TBC is significantly reduced or entirely avoided.