Accession Number : AD0633299

Title :   OXIDATION STUDIES OF TITANIUM BORONITRIDE IN AIR.

Descriptive Note : Technical rept.,

Corporate Author : ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS MATERIALS ENGINEERING DIV

Personal Author(s) : Levitt,Albert P. ; Wong,Philip

Report Date : APR 1966

Pagination or Media Count : 17

Abstract : 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)

Descriptors :   (*CERMETS, *OXIDATION), (*TITANIUM COMPOUNDS, CERMETS), BORON COMPOUNDS, NITRIDES, HIGH TEMPERATURE, HEAT OF ACTIVATION, ROCKET NOZZLES

Subject Categories : Ceramics, Refractories and Glass
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE