Purpose The purpose of this paper is to develop high-performance Au-coated Ag alloy wires (ACAA wires) and demonstrate the effect of Au coating layers on the bonding performance and oxidation resistance for stable and reliable electronic packaging applications. Design/methodology/approach ACAA wire with a diameter of approximately 25 µm and Au layer thickness of approximately 100 nm were prepared by the continuous casting, plating and wire drawing method. The bonding performance of the ACAA wires were studied through bonding on 3,535 chips. The oxidation resistance of ACAA wires and Ag alloy wires (AA wires) were comparatively studied by means of chemical oxidation tests, accelerated life tests and electrochemical tests systematically. Findings ACAA wires could form axi-symmetrical spherical free air balls with controllable diameter of 1.5∼2.5 times of the wire diameter after electric flame-off process. The ball shear strength of ACAA wire was higher than that of AA wires. Most importantly, because of the surface Au coating layer, the oxidation resistance of ACAA wires was much enhanced. Research limitations/implications ACAA wires with different lengths of heat affected zone were not developed in this study, which limited their application with different loop height requirements. Practical implications With higher bonding strength and oxidation resistance, ACAA wires would be a better choice than previous reported AA wire in chip packaging which require high stability and reliability. Originality/value This paper provides a kind of novel ACAA wire, which possess the merits of high bonding strength and reliability, and show great potential in electronic packaging applications.

Four asymmetric α‐diimine dibromide nickel(II) complexes bearing both 2,6‐diisopropyl phenyl and substituted triphenyl {[(C3H7)2C6H3NC(C10H6)CN(R2C6H3)2C6H3]NiBr2, R = CH3, Catal.1; CF3, Catal.2; OCH3, Catal.3; C6H5, Catal.4} were synthesized and characterized. In the presence of B(C6F5)3, these newly synthesized nickel complexes showed high activities toward norbornene (NBE) homopolymerization (0.84–4.88 × 105 gpolymer/molNi‧h) under elevated temperatures, yielding high molecular weight polymers (106.5–657.9 kDa). These Ni/B catalytic systems also efficiently promoted the copolymerization of NBE with n‐butyl methacrylate (n‐BMA) and di(n‐butyl) itaconate (n‐DBI) under 70°C, respectively, affording copolymers with high molecular weight (n‐BMA: 95.0–235 kDa; n‐DBI:35.4–52.5 kDa) and moderate polar monomer incorporations (n‐BMA:1.2–6.4 mol%; n‐DBI:0.8–2.8 mol%). The copolymers with polar groups showed improved solubilities. The unimodal molecular weight distribution of the resultant polymers implied the single‐site catalytic behavior of these nickel catalysts toward NBE (co)polymerization. In addition, both the obtained PNB and the copolymers showed high glass transition temperature (289–345°C) and excellent thermal stability.