Process for forming thermal barrier coating resistant to infiltration

• Main Authors: GORMAN, MARK DANIEL, DYE, DAVID FORREST, ACKERMAN, JOHN FREDERICK, HAZEL, BRIAN THOMAS
• Format: Patent
• Language: English; French; German
• Published: 23.05.2007
• Subjects: BLASTING; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ENGINE PLANTS IN GENERAL; HEATING; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; METALLURGY; NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAMTURBINES; STEAM ENGINES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; WEAPONS

A process for protecting a thermal barrier coating (26). The process entails applying to a surface (32) of the coating (26) a liquid containing one or more of aluminum alkoxides, aluminum beta-diketonates, aluminum carboxylates, and aluminum alkyls. The liquid is applied so as to form a liquid film on the surface (32), and has viscosity and wetting properties that cause the liquid to infiltrate porosity (34) within the coating (26) beneath its surface (32). The coating (26) is then heated to convert the alumina precursor to alumina. A first portion of the alumina forms a surface deposit on the coating surface (32), while a second portion of the alumina forms an internal deposit within the porosity (34) of the coating (26). The surface deposit overlying the coating (26) is available for sacrificial reaction with CMAS, and the internal deposit maintains a level of CMAS protection in the event the surface deposit is breached or lost through spallation, erosion, and/or consumption.