Patent ID: 9073793
Filing Date: 2015-07-07
Classification: C04B,Y10T

Abstract:
1. An environmental barrier coating comprising: at least one transition layer made from a transition layer slurry composition comprising: an outer layer made from an outer layer slurry composition comprising: wherein the primary transition material is selected from the group consisting of mullite, BSAS, and a mullite/BSAS mixture, and the primary outer material comprises BSAS, and wherein the transition layer consists of the primary transition material, any of the first slurry sintering aid dissolved therein, and a first secondary material as a reaction product of the primary transition material and the insoluble portion of the first slurry sintering aid, the outer layer consists of the primary outer material, any of the second slurry sintering aid dissolved therein, and a second secondary material as a reaction product of the primary outer material and the insoluble portion of the second slurry sintering aid, the first and second slurry sintering aids increase rates of diffusion of, respectively, the primary transition material and the primary outer material such that surface area reduction occurs within the transition layer and the outer layer at lower temperatures than would occur absent the first and second slurry sintering aids, and the first and second secondary materials are chosen from the group consisting of rare earth oxides, rare earth disilicates, rare earth monosilicates, rare earth elements, rare earth containing aluminosilicate glasses, rare earth and alkaline earth containing aluminosilicate glasses, rare earth aluminates, phosphorous pentoxide, phosphorous containing aluminosilicate glasses, phosphorous and alkaline earth containing aluminosilicate glasses, aluminum orthophosphate, aluminum oxide, and combinations thereof.