METAL-TO-CERAMIC SEAL TECHNOLOGY STUDY
Final technical rept.
SPERRY GYROSCOPE CO GREAT NECK NY
Pagination or Media Count:
A literature survey on ceramic-to-metal sealing techniques, adherence theory, and allied systems disclosed limited published work and no procedures for achieving ultra-high-strength seals or seals to pure high alumina. Two additional theories were formulated for this study--one proposing the migration of the glass in the ceramic over into the metallizing mixture, and the other recognizing the need for promoting metallized sintering. Three sintering temperatures were chosen, depending on composition, for each of the 200 metallizing mixtures. Each mixture was applied to specimens of 94-, 96-, and 99.6-percent alumina. Testing involved a screening technique whereby the most promising compositions were carried through to increasingly refined test techniques scratch and peel, circumferential seal, and finally tensiles tests. The tensile test specimen was redesigned to eliminate shoulder breaks when evaluating ultra-high-strength seals. Extremely strong seals were developed for all the ceramic bodies considered. A wide variety of sealing compositions was disclosed which produced seals stronger than those previously reported. A method to calculate stresses in ceramic-to-metal seals is theorized. Measurements of the properties of the metal and of residual stresses in seals were made, showing excellent agreement with calculated stresses.
- Adhesives, Seals and Binders