This work is concerned with the preparation and characterization of composite materials prepared by compression molding of a mixture of aluminum flakes and nylon 6 powder. The electrical conductivity, density, hardness and morphology of composites were investigated. The electrical conductivity of the composites is < lo-' S/cm unless the metal content reached the percolation threshold, beyond which the conductivity increased markedly by as much as loll. The volume fraction of conductive filler at the percolation threshold was calculated from experimental data, by fits to functions predicted by the percolation theory. Decreasing the average particle diameter of filler leads to increased percolation threshold (it varies from 23 to 34 vol% for the three different fillers studied] and decreased maximal conductivity of composites. The density of the composites was measured and compared with values calculated assuming different void levels within the samples. Furthermore, it is shown that for certain sizes of particle filler, the hardness decreases initially with the increase of metal concentration, possibly because of poor surface contact with the nylon matrix, but, starting from a certain value, there is a hardness increase. For the smallest particle filler, the hardness of samples is not influenced by the presence of the filler.

The results of an experimental study on the effect of processing variables and filler concentration on the electrical resistivity of conductive composites based on nylon 6 filled with carbon black are reported. A typical percolation behavior in the effect of electroconductive filler content on the resistivity was found. The electrical resistivity of the composites is > 1012 ohm°Cm unless the carbon black content reaches the percolation threshold at ∼9 wt%, beyond which the resistivity decreases markedly by as much as twelve orders of magnitude. Two parameters of molding process—temperature and time—were shown to have a notable effect on the resistivity of composites, whereas pressure has no influence on this property in the pressure range considered. There is no sharp variation in the density due to the onset of percolation, and the hardness of samples is not influenced by the presence of the filler.