Patent ID: 7767305

Claim:
A composite structure, comprising: a porous substrate, having a lower surface and an upper surface and comprising a selected substrate material and having a substrate coefficient of thermal expansion; a first layer integrated with an exposed surface of the substrate, wherein the first layer material comprises between 20 percent and 60 percent molybdenum disilicide, between 40 percent and 80 percent borosilicate glass and a processing aid, with the first layer being positioned adjacent to and between the substrate upper surface and a second layer having a material composition different from the first layer; wherein the second layer material comprises between 5 percent and 70 percent tantalum disilicide, between 5 percent and 30 percent molybdenum disilicide, and between 10 percent and 95 percent borosilicate glass; wherein a composition of the first layer is chosen so that a coefficient of thermal expansion of the first layer is approximately the same as the coefficient of thermal expansion of the substrate; and wherein the combined first and second layers provide a protective layer when exposed to temperatures around 3000° F.