MANUFACTURING METHODS FOR ORGANIC AND INORGANIC FOAMS FOR HIGH-TEMPERATURE RADOME APPLICATIONS.
Abstract
The program goals were to: establish a method for raising the dielectric constants of PBI syntactic foam and lightweight ceramic foam, and match them to the dielectric constant of a PBI laminate; determine methods for sealing organic and ceramic foams against vacuum permeability and moisture absorption; determine thermal, electrical, and mechanical properties of foam sandwich composites (PBI/glass inner and outer skins, PBI and/or a ceramic foam core, and flame-sprayed alumina outer skins); establish a method for fabricating PBI and alumina foam honeycomb sandwich composite panels and define structural, electrical, and thermal properties; define manufacturing problems in fabricating a PBI and/or an alumina foam sandwich composite radome; and determine thermal shock capabilities of PBI and ceramic foams/PBI glass skins (with a flame-sprayed alumina outer skin) and foam sandwich composites. Methods were established for adjusting the dielectric constant of lightweight ceramic (by adding strontium titanate) and PBI foam (by adding aluminum leafing powder). Sealing methods were established for preventing composite water absorption. Materials were screened for possible use as vacuum barriers. Methods were defined for fabricating lightweight ceramic and PBI foams into sandwich composites with 1/2 wave wall microwave characteristics for possible use in radomes. Mechanical, thermal, and electrical data were obtained for these materials and for composite sandwiches. A preliminary thermal/structural analysis was performed for typical sandwich composite missile radomes constructed of PBI foam/PBI glass. Production costs for such typical radomes were projected. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1968
- Accession Number
- AD0837252
Entities
People
- Roland Reed