OXIDATION STUDIES OF TITANIUM BORONITRIDE IN AIR.
ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS MATERIALS ENGINEERING DIV
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The oxidation characteristics of titanium boronitride formed by reactive hot pressing were determined over the temperature range 1010 C to 1425 C. An automatic recording balance was used to determine weight loss versus time at each test temperature for compositions containing 1.5 and 2 moles of excess boron nitride. It was found that a a parabolic rate law holds for oxidation of this material b there was very little difference between the oxidation rates for the two compositions and c the overall activation energy for the process was 28,000 calories per mole. X-ray diffraction analysis of the oxidized surface layer indicated that it was primarily composed of TiO2. The presence of boron oxide was suggested but not positively identified. Possible oxidation reactions are presented and the mechanisms are discussed. It was concluded that titanium boronitride cannot be used for sustained structural service in an oxidizing atmosphere above 1000 C. Author
- Ceramics, Refractories and Glass
- Rocket Engines