Relation Between Particulate Chemistry and Ceramic Properties
Abstract
Progress is described in the first year of a program designed to examine the relation of mechanical properties, grain-growth kinetics and impurity precipitate distribution to the characteristics and chemistry of initial MgO particulates at progressive stages during microstructure evolution. Efforts have concentrated on production of an ultrapure, fully-dense microstructure which will form the standard with which subsequent experiments with doped particulates will be compared. Magnesium oxide vacuum hot pressed specimens were prepared from static and dynamically calcined high purity ( > or = 99.99% MgO) Mg(OH)2 and MgCO3 powders. Microstructure development was studied at stages in the calcining and consolidation processes and it was learned that abnormal grain growth begins at the 70% density level in Mg(OH)2 derived material. Fully dense 1150C hot pressed specimens had a marked duplex structure but pressing at 1450C resulted in material with a normal grain distribution. Grain growth studies were performed at two temperatures on Mg(OH)2 derived material having a normal grain size distribution. A discussion and explanation of the various grain growth studies in MgO is included.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1971
- Accession Number
- AD0717984
Entities
People
- Bernhardt J. Wuensch
- Thomas Vasilos
- William H. Rhodes