Low Thermal Conductivity Ceramic Coatings

Rare earth zirconates have been identified as a class of low thermal conductivity ceramics for possible use in thermal barrier coatings tbcs for gas turbine engine applications.

Low thermal conductivity ceramic coatings. Temperature superalloys and cooling technology over the last six decade 6 1 2 thermal barrier coatings thermal barrier coatings tbcs are widely used in the hot gas path of. Such coatings however are oxygen transparent and do not prevent oxidation of the underlying substrate. These are ceramic coatings with very low thermal conductivity. Despite being typically 1 5 mm thin the allow for a drop of 100 300 o c between the gas and metal surface temperatures.

A novel high entropy material yb 0 2 y 0 2 lu 0 2 sc 0 2 gd 0 2 2 si 2 o 7 5re 0 2 2 si 2 o 7 was prepared by the sol gel method and investigated as a promising environmental barrier coating ebc for sic based composites the results of x ray diffraction and transmission electron microscopy indicated that rare earth elements were distributed homogeneously in the single monoclinic phase. At present coatings are applied as a duplex structure shown schematically in the diagram figure 3. The low thermal conductivity ceramic coatings contribute toward maintaining a large temperature difference between the hot gases in the gas turbine and the superalloy components. The thermal conductivity of calculation meets well with that of experiment.

A novel thermal barrier coating crzr with external low thermal conductivity was prepared. Thermal barrier coatings tbcs are being used for the past few decades for providing thermal insulation to metallic components of hot parts of gas turbine engines. Low thermal conductivity ceramics for thermal barrier coatings p 1764. Rolls royce plc 2 1 thermal barrier coating system thermal barrier coating systems consist of a low thermal conductivity ceramic layer and a metallic bond coat.

The crystal structure and thermophysical properties of crzr coating were analyzed. Fabrication and isothermal oxidation behavior of the co deposited eb pvd nial ysz coating p 1767. To document and com. The thermal barrier is made up of plasma spayed ceramic layer up to 0 6mm thick over an intermediate layer up to 0 7mm thick which usually consists of a metallic bonding coat or of a graded composition ceramic layer designed to minimise thermal mismatch of the adjacent layers.

Thermal barrier coatings tbcs made from ceramics with low thermal conductivities will provide greater insulation relative to the current 7ysz 7 wt yttria stabilized zirconia tbcs and permit. The crzr ceramics can protect the superalloy from the ablation at 1600 c for a.