28-04-2014, 02:59 PM
Thermal barrier coating and method of depositing the combustion chamber same on combustion chamber components
ABSTRACT
Thermal barrier coatings consist of four layers. They are the metal substrate, metallic bond coat, thermally grown oxide, and ceramic topcoat. The metal substrate and metallic bond coat are metal layers and the thermally grown oxide and topcoat are ceramic layers. The metal substrate is typically a high temperature nickel or cobalt alloy. The metallic bond coat is an alloy typically with the composition of NiCoCrAlY. It has a roughened component surface. This layer is responsible for forming the thermally grown oxide when the TBC is subjected to high temperatures. The thermally grown oxide consists of alumina, and this layer protects the substrate from thermal oxidation and corrosion by serving as an oxygen diffusion barrier. Finally, the last coat is the ceramic topcoat. It is composed of yttria-stabilized zirconia (YSZ) which is desirable for having very low conductivity while remaining stable at nominal operating temperatures.