Effect of Eutectic Microstructure on the Properties of Ceramic Oxides.
Abstract
Continued development of equipment and techniques to produce well-controlled, directionally solidified oxide eutectic ingots was undertaken. With eutectics exhibiting melting temperatures below approximately 1550C, bottom cooling of contained melts generally resulted in poorly controlled eutectic micro-structures due to the low liquid-solid thermal gradients caused by the thermal insulation of the growing ingot. Various floating-zone, directional solidification approaches were successfully developed which used resistance heaters surrounding and/or in direct contact with the molten ceramic. At eutectic temperatures above approximately 1700C, apparent metal pick-up from the heaters was observed and radiant heating by refractory metal wires was found to be the best approach. The present emphasis is directed toward the growth of high temperature structural materials. Towards this end, a number of ingots of the Al2O3-ZrO2 eutectic containing Y2O3 as a stabilizer have been directionally solidified by the radiatively melted, floating-zone technique. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 14, 1971
- Accession Number
- AD0723818
Entities
People
- Charles O. Hulse
- John A. Batt
Organizations
- United Aircraft Corporation