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Pulsed Microwave Irradiation of Graphite/Epoxy Composites

Published online by Cambridge University Press:  21 February 2011

R. B. James ,
P. R. Bolton  and
R. A. Alvarez
R. B. James
Affiliation:
Sandia National Laboratories, Livermore, CA 94550
P. R. Bolton
Affiliation:
Lawrence Livermore National Laboratory, Livermore, CA 94550
R. A. Alvarez
Affiliation:
Lawrence Livermore National Laboratory, Livermore, CA 94550
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Abstract

We have measured the microwave-induced damage to the near-surface region of a graphite/epoxy composite material for 1.1-μs pulses at a frequency of 2.856 GHz and a pulse power of up to 8 MW. Rectangular samples were irradiated by single-pass TE10 traveling wave pulses inside a WR-284 waveguide, and in situ and post irradiation studies were performed to characterize the material modifications induced by the microwave pulses. The results of the time-resolved optical measurements in vacuo show that surface decomposition of the epoxy resin occurs for incident pulse powers exceeding 1.1 MW, and that the surface damage is accompanied by a large increase in the reflected microwave power. Simultaneous with the onset of surface decomposition, significant light emission from the sample and a large enhancement of the gas pressure in the test cell were observed. The large increments in both the reflected power and light emission are attributed to the formation of a plasma due to electrical breakdown of the gas at (or near) the sample surface.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 124: Symposium M – Microwave Processing of Materials I , 1988 , 201
Copyright
Copyright © Materials Research Society 1988

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References

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