OXIDATION OF ULTRA HIGH TEMPERATURE CERAMICS IN WATER VAPOR

摘要

The environmental durability of three compositions of UHTCs was evaluated for potential use in propulsion applications. These materials were exposed to a 90% water vapor and 10% oxygen environment at temperatures between 1200 and 1400℃ at 1 atm. The results were compared with tests ran in a stagnant air furnace and with HPBR results. Low velocity water vapor does not have a significant effect on the oxidation rates as compared to stagnant air. Gas velocity is an important contributor to volatility, spallation and accelerated recession of UHTC materials. These UHTC materials are inappropriate for long term aeropropulsion applications because of rapid oxidation and material recession rates in combustion environments.