Effect of chemical etching of resistance wire surface on the strength and failure mechanism of the resistance‐welded joint of polyetherimide composites

Abstract

ABSTRACT The surface modification of stainless‐steel (SS) mesh was carried out by chemical etching for different time, and then, the etched SS meshes were used as the interlayer heating element for resistance welding of glass fabric‐reinforced polyetherimide (GF/PEI) composite laminates. The hydrophobicity and tensile strength of the etched and untreated SS wires and interfacial shear strength (IFSS) between SS wire and PEI resin were investigated by dynamic contact angle (DCA) analyzer and single fiber pull‐out test to evaluate the influence of the degree of chemical etching on the bonding strength of PEI resin and SS surface. Tensile lap‐shear strength (LSS) and scanning electron microscope (SEM) analysis were performed to investigate the welding interface strength and fracture morphologies of the resistance‐welded joint of the GF/PEI laminates. The hydrophobicity and tensile strength of SS wires were increased and decreased respectively with etching time ( t e ). The IFSS of SS wire/PEI resin showed an improvement with t e . The LSS was increased first and then decreased with t e , and the optimal t e was 30 min when LSS reached the maximum. Fracture analysis showed the main failure mode of the welded joints was the interlayer debonding when welding time ( t w ) was insufficient. With the extension of t w , the failure mode gradually switched into the intralayer tearing of the SS implant. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47879.