TRANSPORT PROCESSES IN CERAMIC OXIDES
Abstract
Progress is described in a program intended to clarify the nature of mass transport in MgO, a ceramic oxide. The objectives of the program were to (1) prepare single crystals of purity and perfection superior to those presently available, (2) develop techniques permitting study of stable isotope diffusion and apply them to cation self-diffusion in MgO, and (3) extend measurement of impurity cation and cation self-diffusion coefficients to temperatures as close to the melting point of MgO as possible, in an attempt to reveal a region of intrinsic diffusion. Measurements of cation self-diffusion rates obtained for MgO are tentatively represented by a pre-exponential term, Do, equal to 0.0035 sq cm/sec and an activation energy of 3.13 eV, confirming a surprisingly large value reported elsewhere on the basis of data obtained over a very limited temperature range. Diffusion rates in high purity crystals are smaller by a factor of 2, and transport is interpreted as extrinsic. Measurements of Ni(2+) diffusion in MgO have been extended to 2460C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 15, 1970
- Accession Number
- AD0709975
Entities
People
- Bernhardt J. Wuensch
- Philip E.
- Thomas Vasilos
- William H. Rhodes