Monolithic Transformation of Ceramic Materials from Metal-Organic Sols and Gels
Abstract
The process used to form monolithic transparent Al2O3 bodies from metal-organic starting materials at low temperature via the gel process involves essentially four steps: hydrolysis, peptization, gel formation, and pyrolysis. Each step has been systematically investigated by modification of associated variables in order to determine the combination of factors which produces optimum results. It has been found that the interparticle distance, that is, the extent of approach attained by colloidal particles, at the point of gelling is of critical importance in maintaining monolithicity during the gel-oxide conversion. Minimization of this distance not only reduces the amount of shrinkage necessary during liberation of organics, allowing the body to remain in one piece, but also appears to allow interparticle bond formation during drying and pyrolysis, possibly involving hydroxyl and alkyl groups. For this reason, the factors that provide for the closest approach of gel particles were given particular attention in this investigation. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 20, 1979
- Accession Number
- ADA074181
Entities
People
- B. E. Yoldas
- D. M. Mattox
- D. P. Partlow