Adhesive bonding between aluminium and polytetrafluoroethylene

Requirements to join dissimilar materials are more and more frequent in new technologies. The paper deals with a study of a joint between aluminium pieces and polytetrafluoroethylene (PTFE) pieces. The way of their joining is described. The joint was performed through soldering with adhesive that covered on joining surfaces of the pieces, processed at a certain roughness, in a well-established thickness layer. Initial, the surface PTFE pieces were covered with a thin and uniform sodium metal sheet. The joint was achieved through particular procedure of soldering, simultaneous with plastic deformation of the metal. Various tests of the joint were carried out under conditions simulating service conditions. A piece joint was tested in terms of its strength, thermal resistance and tightness. The tests showed a very good tightness of the joint at high vacuum (1.333×10−9 mbar), in conditions of repeated thermal shocks, in the range of temperatures between −195.5 and 270 °C. The study took into account the requirements of the particular tests and relevant foreign standards, including ASTM and DIN.