Title

Sol Gel Processing of Low Permittivity, Fiber-Reinforced SiO2-Polyimide Substrates

Abstract

Low permittivity ceramic substrates with a sandwich structure consisting of a porous, fiber-reinforced SiO2 core and two thin polymer plates were fabricated by sol-gel processing, and polymer infiltration. The rheological behavior of an aqueous colloidal SiO2 sol, containing short SiO2 fibers was studied as a function of particle loading, fiber loading and gelation time. Short SiO2 fibers were introduced to limit drying shrinkage and thus minimize substrate cracking during drying. After the psuedoplastic sol was tape cast and sintered at 1150°C for 2 h, a polyimide solution was infiltrated into the porous SiO2 core. Permittivities ranging from 1.81 to 3.08 could be obtained by using 32-42% SiO2, 5-50% polyimide and 63 to 8% porosity. The substrate strength was increased from 1.93 MPa to 3.83 MPa after polyimide infiltration.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Composite; Permittivity; Silica; Sol-gel; Substrate; Composition; effects; Gelation; Infiltration; Polyimides; Porosity; Rheology; Sandwich structures; Pseudoplastic sols; Fiber reinforced plastics

International Standard Serial Number (ISSN)

0928-0707

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1997 Springer Netherlands, All rights reserved.

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