THE DEVELOPMENT OF SILICA HOLLOW MICROSPHERES FOR USE AS A HIGH TEMPERATURE DIELECTRIC
Abstract
Silica microbubble material was produced by 2 routes. The direct process melts particles of silica and expands them into bubbles at 1700 C. Yields of only 5%, primarily because of loss as slag, excessive fuel requirements, and the relatively high true density, 0.8 g/cc, of the produce, made the other process more desirable. Acid-leaching of the 16% sodium glass bubbles, which are made commercially at 950 C, followed by dehydration at 1140 C, gave a product having a true density of 0.26 g/cc. It had a slightly lower dielectric constant, 1.11 to 1.2, and equivalent loss tangent values, less than 0.001, at all frequencies and temperatures below 400 C. Both materials were bonded into sheet structures using cold set cement type bonds without serious degradation of the dielectric properties. These structures withstand moderate loads at 1100 C and do not collapse at 1300 C. Densities range from 0.6 to 1.2 g/cc.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1961
- Accession Number
- AD0268089
Entities
People
- J. W. Leforge
- R. S. Lothrop