Patent ID: 8729161

Claim:
An environmental barrier coating comprising: at least one transition layer comprising a doped primary transition material containing a primary transition material of a rare earth disilicate, at least one sintering aid dissolved in the primary transition material, and at least one doping composition selected from the group consisting of iron, aluminum, titanium, gallium, nickel, boron, alkali metals, alkaline-earth metals, and Lnb rare earth metals, the transition layer being made from a transition layer slurry comprising: from about 1 wt % to about 99.9 wt % water; from about 0.1 wt % to about 72 wt % of the primary transition material; and from about 0.1 wt % to about 25 wt % of the at least one slurry sintering aid, wherein the slurry sintering aid is a composition that dissolves in the primary transition material at a sintering temperature of the primary transition material, increases a rate of diffusion of the primary transition material during sintering such that surface area reduction occurs at lower temperatures than would occur in the absence of the slurry sintering aid, and forms with the primary transition material the doped primary transition material containing the rare earth disilicate and the at least one doping composition; optionally, any one or more of: an outer layer made from an outer layer slurry comprising: from about 1 wt % to about 99.9 wt % water; and from about 0.1 wt % to about 72 wt % primary outer material; and a compliant layer made from a compliant layer slurry comprising: from about 1 wt % to about 99.9 wt % water; and from about 0.1 wt % to about 72 wt % primary compliant material.