Abstract
In this study, we investigated the deterioration behavior of epoxy resin and its adhesive joint with Ni by water absorption. The water absorption characteristic was evaluated by an immersion test, and the deterioration behavior of the Ni/resin interface was evaluated by a tensile test after a thermal humidity test（ THT）. As a result, it was clarified that the water absorption behavior of the epoxy resin obeys the Fick's second law and the tensile strength of the resin decreases by water absorption. The tensile strength of the Ni/resin interface tended to decrease by the THT, and the main fracture mode was the interfacial fracture. Furthermore, in order to evaluate the deterioration life of the Ni/resin interface, Fourier transform infrared spectroscopy analysis of the fracture surface after the tensile test was conducted to determine the water absorption degree（Dw）. The apparent activation energy was calculated from the Arrhenius plot obtained by the deterioration lifetime defined by the specific value of Dw. The apparent activation energy due to deterioration of the Ni/resin interface was 11.5 kJ/mol.
