Abstract: A method for in-frame repairing of a thermal barrier coating (12) on a gas turbine component includes cleaning a desired surface portion (10) of the component without removing the component from the gas turbine. The method also includes roughening the surface portion in-frame, applying a bond coat (68) to the surface portion in-frame, and applying a ceramic topcoat (70) to the bond coat, in-frame. A system (28) for cleaning the surface portion in-frame includes an abrasive media (34) having a state change characteristic occurring at a temperature lower than an operating temperature of the gas turbine so that the abrasive media changes from a solid state to another state allowing the media to exit the gas turbine during operation. The system also includes an abrasive media sprayer (36) to direct a spray of the abrasive media at the desired surface portion.

Abstract: A braze material (10) including nano-sized filler material particles (14). The nano-sized particles will melt at a temperature significantly lower than the micron-sized particles used in prior art braze materials, thereby eliminating or reducing the need for the addition of temperature depressant materials such as boron or silicon. The resulting braze joint is substantially free of detrimental boride and suicides phases, thereby improving the material properties of the joint, eliminating the need for a separate post-braze diffusion heat treatment, and permitting a subsequent welding operation with reduced risk of cracking. The braze heat treatment may also function as a solution heat treatment, a pre-weld heat treatment or a post-weld heat treatment.

Abstract: A method for in-frame repairing of a thermal barrier coating (12) on a gas turbine component includes cleaning a desired surface portion (10) of the component without removing the component from the gas turbine. The method also includes roughening the surface portion in-frame, applying a bond coat (68) to the surface portion in-frame, and applying a ceramic topcoat (70) to the bond coat, in-frame. A system (28) for cleaning the surface portion in-frame includes an abrasive media (34) having a state change characteristic occurring at a temperature lower than an operating temperature of the gas turbine so that the abrasive media changes from a solid state to another state allowing the media to exit the gas turbine during operation. The system also includes an abrasive media sprayer (36) to direct a spray of the abrasive media at the desired surface portion.

Abstract: A method of depositing a zirconia-based ceramic coating (24) using a low velocity oxy-fuel (LVOF) process. Particles of zirconia (14) are mixed with second constituent particles (16) of a material having a melting temperature sufficiently low to be successfully deposited by an LVOF process. The second constituent particles may have a coefficient of thermal expansion within 30% of that of the zirconia particles, and/or they may have a thermal conductivity less than or no more than 20% higher that that of the zirconia particles. The second constituent particles may include calcium titanate, strontium titanate or sodium-zirconium-phosphate-silicate (NZPS). The capability to deposit the zirconia-containing particle mix with an LVOF process facilitates the in-situ repair of a component having a damaged zirconia-based thermal barrier coating.

Abstract: A yttria stabilized zirconia ceramic thermal barrier coating (24) is applied to a substrate (22) using an oxy-acetylene spraying process by including in the coating a eutectic phase having a melting temperature sufficiently low to cause melting of the eutectic phase during the oxy-acetylene spraying process. The eutectic phase may be present in the powder (12) used for the spraying process, or it may be formed during the spraying process by the oxidation of a layer of metal applied to yttria stabilized zirconia particles. The use of an oxy-acetylene spraying process facilitates the application of the coating during in-frame repair of a gas turbine component.

Abstract: A braze material (10) including nano-sized filler material particles (14). The nano-sized particles will melt at a temperature significantly lower than the micron-sized particles used in prior art braze materials, thereby eliminating or reducing the need for the addition of temperature depressant materials such as boron or silicon. The resulting braze joint is substantially free of detrimental boride and suicides phases, thereby improving the material properties of the joint, eliminating the need for a separate post-braze diffusion heat treatment, and permitting a subsequent welding operation with reduced risk of cracking. The braze heat treatment may also function as a solution heat treatment, a pre-weld heat treatment or a post-weld heat treatment.