AbstractThe effect of PVA (polyvinyl alcohol) concentration and the immersion time of the Fe40Ni40B20ribbon was studied in terms of interfacial shear strength. First, the PVA concentration was constant at 9 wt% while the immersion time of the ribbon is the solution was changed form 20 to 200 h. Second., the immersion time was constant at 144 h while the concentration of the PVA was changed form 1 to 12 wt%. The interfacial shear strength improved only slightly by increasing the immersion time from 20 h (0.55 ± 0.09 MPa) to 100 h (0.86 ± 0.12 MPa). The interfacial shear strength increased sharply form 0.86 ± 0.12 MPa at 100 h of immersion time to 3.02 ± 0.66 MPa at 144 h of immersion time. After 144 h of immersion, the interfacial shear strength almost leveled off (2.97 ± 0.26 MPa) at 200 h of immersion. The surface of the polypropylene (PP) after pullout and just before the ribbon fracture was studied with a scanning electron microscope (SEM). The low interfacial shear strength of composites immersed for less than 100 h is related ot the insufficient coating on the ribbon and a lack of the well developed interfacial zone. This is manifested by the presence of circumferential bands and impression from rough marking of the ribbon contact side left on the PP surface. The presence of parabolic markings and growth of spherulites on the PP surface may explain the higher interfacial shear strength observed at longer immersion times in the PVA, which suggests the existence of the well developed interfacial zone between ribbon and the PP matrix. The effect of PVA concentration on interfacial shear strength is almost similar to the effect of immersion