Electrical and tribological properties of gradient epoxy-graphite composites

Purpose: The goal of this work was to use gravity casting as a method to prepare composite material that is characterized by gradient of electrical and tribological properties. Furthermore electrical and tribological properties of composites filled with two different kinds of graphite were compared. Design/methodology/approach: In this research the method of preparing polymeric gradient composites was gravity casting. The experimental procedure focused on evaluating the electrical resistivity and coefficient of fraction (by the pin-on-disc method) of gradient composites. Findings: Gravity casting method allowed to obtain materials with different percentage of graphite content in subsequent layers of composite. Moreover it was observed that values of coefficient of friction were higher for composite with SV94 graphite than for composite with PV60/95. Research limitations/implications: The main problem for this work was to obtain continuous change of properties depending on the distance from surface. The particle's diameter distribution, shape and size of reinforcement were significant in manufacture of composites and influenced gradient of tested properties. Practical implications: Method applied in this research allowed to obtain materials that are characterized by gradient of electrical and tribological properties. Such composites find applications in electrical industry and in mechanical engineering. Originality/value: New polymeric gradient materials were developed using gravity casting technique. Electrical and tribological properties of these composites were determined depending on distance from the surface of the test piece.