Effect of Space Environment on the Reliability of Conductive Adhesive Joints

Conductive adhesive bonding technology is widely used in the lightweight microwave components of satellite payloads. In the space environment, the conductive adhesive is subjected to the coupled action of irradiation and temperature cycling. In this paper, the 60Co γ-ray radiation test and temperature cyclic accelerated life test were carried out for the conductive adhesive joints. Subsequently, the reliability of the conductive adhesive joints for aerospace applications was investigated to examine the shear strength and electrical resistivity. The results of irradiation test show that the electrical conductivity and mechanical properties of the conductive adhesive joints are not affected when they are irradiated by < 120 Krad (Si). In the accelerated life test with temperature cycling, the cumulative failure ratios under different cycles are obtained by monitoring the change of electrical resistivity, and the Weibull distribution model of conductive adhesive joints is established. By adopting the Coffin-Manson model, the shortest average life of the conductive adhesive joint in the geostationary satellite is about 32.6 years, and the minimum reliability is found to be 97.8% when the in-orbit life is 8 years.