Pulsed Microwave Irradiation of Graphite/Epoxy Composites,
SANDIA NATIONAL LABS ALBUQUERQUE NM
Pagination or Media Count:
We have measured the microwave induced damage to the near surface region of a graphiteepoxy composite material for 1.1-microsecond pulses at a frequency of 2.865 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 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, we observe significant light emission from the sample and a large enhancement of the gas pressure in the test cell. The large increments in 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.
- Ceramics, Refractories and Glass