Improved formulations of an interface material are described. These formulations may, in at least some cases, match and/or accommodate dimensional changes in the part and/or support structure throughout thermal processing (e.g., debind and sintering, or sintering only). Furthermore, these formulations may also maintain the property of resisting bonding between the interface and the part and/or support structure while also maintaining a physical separation between the part and support structure. In some cases, an improved interface material may accommodate strain associated with the shrinkage of a part (and optionally support structure) during sintering while also minimally impacting the ability of the part (and optionally support structure) to shrink or otherwise change in dimension. In some cases, the interface material may include one or more fugitive phases that are removed during thermal processing (e.g., through pyrolysis of the fugitive phase(s)).

A castable refractory composition may include from 5% to 95% by weight of alumina, aluminosilicate, or mixtures thereof; from 0.5% to 1.5% by weight alkaline earth metal oxide and/or hydroxide, and 0.1% to 5% by weight of silica having a surface area of at least about 10 m.sup.2/g. The refractory composition may include no more than 0.5% by weight of cementitious binder. The refractory composition may release less than 25 cm.sup.3 of hydrogen gas per kilogram of castable refractory composition upon addition of water. The refractory compositions may set on addition of water.

This relates to a turbine blade comprising a preformed fibrous fabric of fibres consisting of carbon, silicon carbide or rhenium fixed with a binder resin, and wherein the preformed and fixed fibrous fabric is coated and infiltrated, respectively, with B.sub.4C, wherein the preformed fibrous fabric that has been fixed and coated and infiltrated, respectively, with B.sub.4C further has a multilayer coating consisting of at least one layer of silicon carbide and at least one layer of a metal boride, a metal nitride or a metal carbide, and wherein an oxide ceramic is applied over the multilayer coating. The turbine blade is resistant to high temperatures and is particularly well suited for use in a gas turbine. Methods for producing the turbine blade are also described.