Surface modification of a duplex stainless steel for plastic-metal hybrid parts

Purpose: Of this paper is the evaluation of three different surface treatments on a duplex stainless steel, in order to improve its adhesive properties on a thermoplastic like polysulfone. Design/methodology/approach: In order to improve the adhesion between stainless steel and polysulfone, shot-peening, acid (aqua regia) etching and atmospheric pressure plasma jet have been used. The topography and surface activation effects have been evaluated by means of SEM and contact angle measurements. Additionally, aging studies have been performed to evaluate the effect of storage time of parts on atmospheric plasma torch surface treatment. Finally, to test the effectiveness of the treatments, it has been carried out successfully shear strength tests by tension of adhesive assemblies previously modified with the treatments. It has been also examined rupture failures that have occurred in these assemblies. Findings: Aqua regia and plasma torch treatments have reached the optimal surface modification condition under wettability criteria. Shear strength tests demonstrated that the improved surface adhesion provided on this substrate and the polysulfone is achieved by shot-peening and acid etching treatments. Research limitations/implications: A deeper analysis varying several conditions like humidity could be suggested in order to evaluate the effectiveness of surface treatment. Originality/value: Up to now there is no any study in the literature about the comparison of different surface treatment on duplex stainless steels and the subsequent evaluation of the adhesion of a polymer like polysulfone.