Relationships between oxygen diffusion characteristics of polycrystalline and single crystal 2MgO · TiO2
1977; Elsevier BV; Volume: 50; Issue: 3 Linguagem: Inglês
10.1016/0009-2614(77)80366-7
ISSN1873-4448
AutoresS. Shirasaki, Isamu Shindo, Hajime Haneda, Masayuki Ogawa, K. Manabe,
Tópico(s)Magnetic Properties and Synthesis of Ferrites
ResumoSelf-diffusion coefficients of oxygen in both polycrystalline and single crystal 2MgO·TiO2 have been measured at an ambient oxygen pressure of about 40 mm Hg over the temperature range 1080–1450°C. A convenient method to estimate the volume diffusion coefficient, D1, of this polycrystal in which the relative magnitude in Dg (grain boundary diffusion coefficient) with respect to D1 falls between two extremes, i.e., Dg = D1 and Dg ⪢ D1, is newly proposed, and its plausibility is examined by comparing the resultant D1 with that of single crystal 2MgO·TiO2. Not only the magnitude but also the temperature dependence of the “apparent” diffusivity of these polycrystalline particles considerably varied with their particle size. The reason for this semiquantitatively interpreted in terms of the relative magnitude of Dg with respect to D1.
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