Structure and thermophysical properties of polytetrafluoroethylene-aluminum composite materials produced by explosive pressing

Metal filled composite materials on the basis of polytetrafluoroethylene (PTFE) are widely used in tribotechnical units of different equipment. Amongst the metal fillers for PTFE, aluminum is the most perspective, it has high thermal conductivity and low density, which is relevant for the aircraft industry. Due to low adhesion of PTFE to metals, the thermal conductivity and strength properties of these CM are low, so it is perspective to use explosive pressing (EP) which provides the conditions for an increase in physical-chemical interaction between CM components. The work researches the influence of EP on the structure, thermal expansion and thermal conductivity of composite materials on the basis of PTFE containing 10 and 30% vol. of aluminum. It has been established that EP, as well as sintering in a closed volume, contributes to a decrease in thermal expansion and an increase in the thermal conductivity of composite materials, which is connected to structural changes accompanied by an intensification of adhesive interfacial interaction. At the same time, with an increase in aluminum concentration, the efficiency of EP increases due to the increase in the number of contacts between metal particles, as well as the occurrence of an interphase zone, with peculiar properties.