Oxidation of Tungsten at Ultra-High Temperatures
LOCKHEED MISSILES AND SPACE CO INC SUNNYVALE CA
Pagination or Media Count:
The oxidation behavior of tungsten in air and oxygen has been studied as a function of pressure 0.1 to 5.0 mm Hg and gas dynamics at temperatures from 1,300 to 3,3500C 2,370 to 6, 0600F. The development of a surface recession technique for rate meas urement in static and dynamic atmospheres at low pressures is described. Grain size and orientation are shown to influence the rate of oxidation. Transport of oxygen In the system is a rate-limiting factor in static or turbulent air. Oxygen partial pressure in the reaction chamber varies with the temperature, surface area, and system geometry. High-velocity jet impingement is required to provide a known and constant value of oxygen pressure. Gaseous transport is not rate limiting In pure oxygen at pressures below 3 mm Hg and temperatures to 2,2000C 3,9900F. Identical oxidation rates are obtained by tests In static, turbulent, or high-velocity oxygen and high-velocity air.
- Inorganic Chemistry
- Metallurgy and Metallography