A Study of Millimeter-Wave Sintering of Fine-Grained Alumina Compacts
Abstract
A number of high-frequency microwave sintering studies of alumina have reported that sintering proceeds much faster in microwave furnaces when compared to conventional furnaces, and that densification can occur at lower temperatures. These differences have motivated the search for a nonthermal microwave enhancement effect such as the time-averaged microwave field-induced mass transport effect proposed by Rybakov and Semenov. To assess the difference between microwave and conventional sintering and the presence of a nonthermal effect in microwave sintering, a study of millimeter-wave (35 GHz) sintering has been conducted at the Naval Research Laboratory using a well-studied fine-grained (submicron) commercial alumina with reproducibly manufactured properties, Sumitomo AKP-50%. This report describes our results that generally indicate no large differences in the required temperatures for densification of conventionally and microwave-sintered compacts or between the resulting microstructures. The nonthermal microwave effect of Rybakov and Semenov has been estimated for alumina and found to be small.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 06, 1998
- Accession Number
- ADA354348
Entities
People
- Arne W. Fliflet
- D. Lewis
- L. K. Kurihara
- R. P. Fischer
- R. W. Bruce
Organizations
- United States Naval Research Laboratory