Relationships between oxygen diffusion characteristics of polycrystalline and single crystal 2MgO · TiO2

✍ Scribed by S. Shirasaki; I. Shindo; H. Haneda; M. Ogawa; K. Manabe

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 354 KB
• Volume: 50
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(77)80366-7

✦ Synopsis

Self-diffusion coefficients of oxygen in both polycrystalline

and single crystal 2MgO.TiO~ 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, D 1, of this polycrystal in which the relative magnitude of Dg (grain boundary diffusion coefticient) with respect to D 1 falls between two extremes, i.e.. Dg = D1 and Dg 9 D1, is newly proposed, and its plausibility is examined by comparing the resultant D1 with that of single crystal 2Mg0.TiOz. Not only the magnitude but also the tcmpe rature dependence of the "apparent" diffusivity of these polycrystalline particles considerably varied with their particle size. The reason for this is semiquantitatively interpreted in terms of the relative magnitude of Dg with respect to D 1.