Robust Environmental Barrier Coatings for Silicon Nitride

Silicon based ceramics are the leading candidates for the high temperature structural components of the advanced propulsion engines. For such applications, one key drawback of silicon based ceramics is the volatilization of the protective silica scale in engine relevant oxidizing and water vapor environments at temperatures up to 1500 degrees C. Thus for the realization of silicon based ceramic components in advanced propulsion engines, environmental and thermal protective coatings will be needed. UES, Inc. proposes to develop a multifunctional environmental barrier coating concept utilizing advanced materials, coating design and coating processing technique for low thermal expansion silicon nitride. The performance and stability of the coatings developed in this program will be determined in relevant engine environments at temperatures up to 1500 degrees C. Based upon the test results coating design and process parameters will be further refined in Phase II.