Accession Number : AD0742857

Title :   Investigation of Ceramics for High Temperature Turbine Vanes.

Descriptive Note : Final rept. 1 Apr 71-31 Mar 72,

Corporate Author : GENERAL ELECTRIC CORPORATE RESEARCH AND DEVELOPMENT SCHENECTADY N Y

Personal Author(s) : Prochazka,Svante

Report Date : MAR 1972

Pagination or Media Count : 69

Abstract : Hot-pressing of a 99.7% pure commercial silicon carbide powder with one percent boron addition has yielded a 99+% dense ceramic with 30 microns tabular grains and 50,000 psi flexural strength. A submicron particle size powder consolidated with 1% boron addition at 1950C gives 108,000 psi strength at room temperature and 64,000 psi at 1500C. Its microstructure is composed of 3.0 microns equiaxed SiC grains and less than 0.5% of free silicon forming isolated grains at the lower temperature and a grain boundary phase and intragranular inclusions at 2100C. No boron containing phase could be detected. The structure is formed by a mixture of various hexagonal poly types with the alpha-6H form prevailing. (Author)

Descriptors :   (*CERAMIC COATINGS, PERFORMANCE(ENGINEERING)), (*TURBINE STATORS, CERAMIC COATINGS), HOT PRESSING, SILICON CARBIDES, BORON, MICROSTRUCTURE, PHASE STUDIES, SINTERING, POROSITY, CRACKS, MANUFACTURING

Subject Categories : Coatings, Colorants and Finishes
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE