Adhesion mechanisms of enamel–varnishes on copper: Adhesion promoter versus corrosion inhibitor

Abstract

ABSTRACT:The role of adhesion promoters, copper oxidation, and thermal aging in the adhesion mechanism of enamel on copper winding wires is investigated. Evidence is presented on the predominant role of the copper oxide at the interface in the wire-enamel adhesion phenomena. The oxidation process and the copper oxides stability at the interface are seen to strongly depend upon the thermal aging of the wire and the nature of both the enamel and the promoter. Atomic force and scanning electron microscopy analyses show that so-called promoters act more efficiently as corrosion inhibitors than as adhesion enhancers.

Understanding Surface Adhesion in Nature: A Peeling Model

“…To meet different situations of surface contact, [74][75][76][77][78][79][80] four kinds of methods based on peeling model have been developed to characterize the surface adhesive force ( Figure 4 ). The most commonly used method is that peeling one end of the sample from the substrate at a certain angle (Figure 4 a).…”

“…[ 78 ] The third method is the twist peel test (Figure 4 c) to qualitatively characterize the adhesive strength of coating in the winding wire industry. [ 79 ] It is performed by fi xing one end of the wire to an anchor, then rotating the other end along the diameter direction at a certain speed until the coating is detached. The rotation number represents the peel strength.…”

“…Although the twist peel test can't quantitatively provide the peel strength, it does allow a comparison among different samples. [ 79 ] The fourth method is the T-peel test (Figure 4 d) to assess the adhesive strength of organic coatings and adhesive joints. [83][84][85][86] In some cases such as polyimide coatings on fl exible substrate, the T-peel test is more suitable for measuring the adhesive strength than the 90° peel test.…”

Improving interfacial adhesion between thermoplastic polyurethane and copper foil using amino carboxylic acids

“…The oxidation of copper is very fast in an air atmosphere. 11,12 Hence, it is very difficult to observe a pure Cu surface. The main oxide types on the Cu surface are CuO, Cu 2 O, Cu(OH), and Cu(OH) 2 .…”

Poly(esterimide) Wire Enamels: Coatings with the Right Combination of Thermal and Mechanical Properties for Many Applications

“…Then agents (e.g., catalysts, crosslinkers)35 – 38 and additives (e.g., leveling agents, adhesion promoters, etc. )39 – 45 are mixed into the solution. Next the product is further diluted in order to adjust viscosity and solid content in the specifications range.…”