Analysis of the Interfacial Adhesion between a Stainless-Steel Fiber and an Epoxy Resin by the Single Fiber Microdroplet Test

In this study, the surfaces of the stainless-steel fibers of the kind primarily utilized in fiber-reinforced composite materials were modified by an acid treatment to increase the interfacial adhesion between the fibers and epoxy resins in composite materials. The interfacial shear strength between the resins and acid-treated fibers was determined by a single fiber microdroplet test, where the resin droplet was located at the center of the fiber. The etching effect at the surface of the fibers increased with the increase in the acid-treatment time. The interfacial shear strength between the stainless-steel fiber and epoxy resin increased with the increase in the specific surface area of contact between the fiber and resin. Furthermore, there was no significant deterioration in the mechanical properties of the stainless-steel fibers with the increase in the surface etching effect. The modification of the surfaces of the stainless-steel fibers by the acid treatment resulted in an increase in the interfacial shear strength between the fibers and resins. Thus, this study demonstrated the possibility of widening the scope of the applications of stainless-steel fiber/epoxy resin composites.