The effect of the filled epoxy resin interlayers on the adhesion in polymer-metal hybrid joints

Two epoxy resin compounds were used as the adhesion interlayers at the interface between an injected glass fibre reinforced thermoplastic polymer PA6GF30 (polyamide 6 with 30% wt. of glass fibres) and steel sheet (DC01 steel, 0.5 mm thick). Both epoxy resins, Epidian62 and Epidian57, were filled with alumina particles (grain size of 3 µm ± 1%) in a volume rate of 100:29 epoxy resin - alumina. Steel sheets with cured layer of epoxy resin compounds were placed in the injection mold, then the PA6GF30 was injected between them. Shear strength tests were basis for the evaluation of the adhesion of the manufactured polymer-metal hybrid joints. SEM and optical microscopy analysis were used to investigate the structure of joints after shear deformation. Conversion rates of epoxy compounds and heat of curing reactions were investigated by using of differential scanning calorimeter (DSC). It was found that the highest strength of these joints was achieved for epoxy compounds based on Epidian62.