Abstract
For the stabilization of insulation performance in the resin-molded insulators, strong adhesion between the resin and metal is required. In this paper, influence of surface roughness for interfacial strength between the resin and metal was investigated. Test pieces were made by covering Cu and SUS cylinders, which have some values of surface roughness, with epoxy resin. The interfacial strength was evaluated with shearing tests of these test pieces. The effective adhesive surfaces of those cylinders were evaluated from surface observation with a laser microscope. The interfacial strength increased with surface roughness. The adhesion-strength index (μ+B), which had been proposed in previous paper, were calculated with the effective adhesive surface and the interfacial strength. The adhesion-strength index gave a constant value with various surface roughnesses for each metal. We also discussed the multi-scale connection between nano-scale adhesion by using the molecular-dynamics method and macro-scale interface strength. We showed that our proposed interfacial fracture energy (mode I) is effective in determining the adhesion strength of two kinds of interfaces between epoxy resin and metals (Cu and SUS).
