PROCESSING METHODS FOR HIGH-RELIABILITY SILICON-NITRIDE HEAT ENGINE COMPONENTS

The paper discusses highlights of a silicon nitride processing methodo logy that has been developed in the course of a major four-year DoE fu nded program in processing for reliability. The program focused on the attainment of high strength and reliability through the identificatio n and subsequent control of strength-degrading flaws introduced during processing unit operations. Process control and NDE methods applied t o achieve an optimized process with the potential to produce high-reli ability advanced heat engine components are discussed. Concluding rema rks are directed to the extensive tensile strength database that has b een generated through testing of over 300 tensile rods produced by the optimized process.