Coating material for thermal barrier coating having excellent corrosion resistance and heat resistance and method of producing the same

A coating material for a thermal barrier coating having excellent corrosion resistance and heat resistance comprising a substrate, an undercoat made of an aluminum-containing heat-resistant alloy, Al2O3 layer produced on the surface of the undercoat by preferentially oxidizing Al in the components of the undercoat in the presence of Cr2O3 layer and Cr2O3 layer formed thereon as a middle layer on the undercoat, and a top coat made of ZrO2 based ceramic.

A method of producing a coating material for a thermal barrier coating having excellent corrosion resistance and heat resistance, which comprises forming an undercoat made of a heat-resistant alloy having an Al content of 3-24 mass % on a surface of a substrate through spraying process or an electron beam deposition process, forming a middle layer of Cr2O3 layer having a thickness of 0.2-10 μm by repeating a procedure of applying an aqueous mixed solution of one or more of chromic anhydride, ammonium chromate and ammonium bichromate and firing under heating at 500-900 K for 1-5 hours one time or plural times, and forming a top coat of ZrO2 based ceramic on the middle layer through a spraying process or an electron beam deposition process.

A method of producing a coating material for thermal barrier coating having excellent corrosion resistance and heat resistance, which comprises forming an undercoat made of a heat-resistant alloy having an Al content of 3-24 mass % on a surface of a substrate through spraying process or an electron beam deposition process, forming a middle layer of Cr2O3 layer having a thickness of 0.2-10 μm by repeating a procedure of applying an aqueous mixed solution of one or more of chromic anhydride, ammonium chromate and ammonium bichromate and firing under heating at 500-900 K for 1-5 hours one time or plural times, heating in an atmosphere or under vacuum or in an inert gas atmosphere at 1200-1500 K for 1-20 hours to form an Al2O3 layer produced through preferential oxidation reaction of Al contained in the under coat on the surface of the undercoat just beneath Cr2O3 layer as a part of the middle layer, and forming a top coat of ZrO2 based ceramic on the middle layer.