US 7,407,718 B2 · Thermal/environmental barrier coating system for silicon-containing materials

Abstract

A coating system for Si-containing materials, particularly Si-based composites used to produce articles exposed to high temperatures. The coating system is a compositionally-graded thermal/environmental barrier coating (T/EBC) system that includes an intermediate layer containing yttria-stabilized hafnia (YSHf) and mullite, alumina and/or an aluminosilicate, which is used in combination with an inner layer between a Si-containing substrate and the intermediate layer and a thermal-insulating top coat overlying the intermediate layer. The intermediate layer provides environmental protection to the silicon-containing substrate, and has a coefficient of thermal expansion between that of the top coat and that of the inner layer so as to serve as a transition layer therebetween. The intermediate layer is particular well suited for use in combination with an inner layer of an alkaline earth metal aluminosilicate (such as BSAS) and a top coat formed of YSZ or YSHf.

Claims20

Dependent claims

A coating system on an article having a substrate formed of a silicon-containing material, the coating system comprising:

an inner layer overlying the substrate and containing an alkaline earth metal aluminosilicate;
an intermediate layer overlying the inner layer, the intermediate layer consisting essentially of an yttria-stabilized hafnia and at least one material selected from the group consisting of mullite, alumina, and aluminosilicates;
and
a top coat overlying the intermediate layer and formed of a thermal-insulating material that contains yttria and is chemically reactive with the alkaline earth metal aluminosilicate in the inner layer at temperatures above about 1370° C.;
wherein the intermediate layer contacts the inner layer and the top coat, has better resistance to chemical interaction with the alkaline earth metal aluminosilicate in the inner layer than the thermal-insulating material, and has a coefficient of thermal expansion between that of the thermal-insulating material and that of the inner layer.

2 more elements

Dependencies are inferred from the claim text.

Thermal/environmental barrier coating system for silicon-containing materials

Life of this patent

Thermal/environmental barrier coating system for silicon-containing materials

Life of this patent

Abstract

Claims20