Transport Processes in Ceramic Oxides
Abstract
Final results are summarized for a program designed to clarify the nature of mass transport in MgO through growth of crystals of improved perfection and purity, measurement of cation self-diffusion rates with the aid of a stable isotope tracer over a wide range of temperatures, and extension of impurity cation and cation self-diffusion measurements to temperatures as close as possible to 2800C, the melting point of the material. Crystals of MgO 2 cm in diameter and up to 2 mm in thickness have been grown epitaxially on MgO substrates with the aid of chemical vapor transport with HCl at 1000C. Growth rates up to 100 micron/hr. have been achieved. Purification results from the process, and negligible concentrations of transport agent are incorporated in the deposit. Cation self-diffusion coefficients have been determined over a temperature range of 1100 - 2400C. Measurements of Ni(2+) diffusion in MgO have been extended to 2460C (0.88 T(m)). No difference in transport behavior is noted for crystals of moderate purity and crystals of the best quality commercially available at present.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 1971
- Accession Number
- AD0732032
Entities
People
- Bernhardt J. Wuensch
- Philip E. Gruber
- Thomas Vasilos