In-flight Behavior and Deposition Mechanism of Copper Coating on Polyacetal Resin Substrate

Abstract

Low-power microwave plasma spraying of low electrical resistivity Cu coating on polyacetal has been developed for direct printing of electric wire onto resin-based material without any interlayer, and the deposition mechanism has been investigated. Deposition behavior of Cu spray particles on POM substrate during spraying was classified into three types such as embedding, splash, and rebound. In the case of rebound, molten Cu particles vaporize the substrate material and rebound from the substrate by inverse Leidenfrost phenomena. In case of embedding, molten Cu particles are embedded on the substrate by melting the substrate surface and mechanical anchoring between particle and the substrate. The sprayed coating achieved higher adhesion strength about 3.0 MPa between the coating and substrate. Also, hydrogen addition to argon working gas and use of extension tube as gas shroud enhanced the oxide reduction and achieved lowest electrical resistivity Cu coating with lowest electrical resistivity of 0.049 μΩm, which is equivalent to 35%IACS.