SELF-DIFFUSION OF OXYGEN IN SINGLE CRYSTAL AND POLYCRYSTALLINE ALUMINUM OXIDE
The self-diffusion coefflcient of oxygen was determined as a function of temperature in single-crystal and polycrystaline aluminum oxide at temperatures up to 1780 deg C. The rate of exchange between a gas phase and solid particles was measured, utilizing the stable isotope O/sup 18/ In single crystals of aluminum oxide intrinsic diffusion occurs in a high-temperature region, depending on temperature as D = 1.9 x 10/sup 3/ exp(-152,000/RT). At temperatures below about 1600 deg C variable results were obtained depending on impurity content and previous heat treatment. For one set of samples experimental results could be represented as D = 6.3 x 10/sup -8/ exp(-57,600/RT). The diffusion coefficient of oxygen in polycrystalline samples is about two orders of magnitude larger than tbat found for the single crysthls, and has a somewhat smaller activation energy. With the polycrystalline oxide, variable results were also observed at lower temperatures. (auth)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-022058
- OSTI ID:
- 4168449
- Journal Information:
- Journal of Chemical Physics (U.S.), Vol. Vol: 33; Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Diffusion in polycrystalline Y/sub 2/O/sub 3/ and Er/sub 2/O/sub 3/
Diffusion of Aluminum, Magnesium, Silicon, and Zirconium in Nickel