Exploratory dielectric study involving ultra-low content of Si-C-Al in epoxy

Ball milling was used to prepare a mixture of Silicon, Graphite and Aluminum, in equal proportion. X-ray analysis (XRD) confirmed that SiC was not produced in the present milling conditions. Aluminum was identified as being partially oxidized. The powder microstructure was found to be rather micrometric in size. Epoxy samples were casted using the Si-C-Al powder as an additive. Neat epoxy and a composite containing 0.1 wt% of the filler were prepared. A series of dielectric tests were performed in order to compare the behavior of neat and composite epoxy. Dielectric responses at 20°C were found to be very similar, whether the excitation field was low or high. However, erosion experiments have allowed to discriminate the performance of the samples, with a definite worsened resistance to discharges from the composite sample.