Oxygen-diffusion characteristics of loosely-sintered polycrystalline MgO

✍ Scribed by S. Shirasaki; M. Hama

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 779 KB
• Volume: 20
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(73)80066-1

✦ Synopsis

Self-diffusion coefficients of oxygen in well-sintered and in loosely-sintered polycrystaltine h&O have bean measured at an ambient oxygen pressure of about 35 mm Hg over the temperature range 1020-1450°C. The osygea diffusion coefficient as a function of temperature of the former specimen is espresseci by a single Arrhenius equation with an activation energy of 55.8 k~:al/mole, white that of The latter is composed of two intersecting lines (E= 60.2 km.l/mole from 1020-1250"C;E = 102.8 kcal/mole from 1250-1450°C). The diffusivity for single-crystd_erati of the well-sintered polycrystal is two orders of magnitude larger than that in the low-temperature portion of the loosely-tintered one. This fact is interpreted in termsof an insufficient dissolution of monovalent cation impurities into the loosely-sintered crystal httice. Two ways of interpretation are given for the preszce of the high-tempsrrtture portion characteristic of the loosely-sintered polycrystal.