Optimizing thin electric functional copper coatings via atmospheric plasma spray: impact of particle temperature and velocity

The objective of this study is to optimize thin (20-40 um) electric functional copper coatings using atmospheric plasma spray (APS) by determining the impact of particle temperature and velocity on coating properties. A particular focus is placed on the formation of the real contact between the particles within the coating, which is crucial for influencing electrical conductivity. The contact at the interface is essential for adhesive strength. The study begins by measuring the temperature and velocity of particles of varying process parameters. Coatings are evaluated regarding the adhesion strength and electrical conductivity. The parameters explored include different temperatures and varying amounts of primary (Ar), secondary (Ar-H2), and additive gases (N2-H2) with the objective of optimizing particle kinetics. The results of this investigation indicate that one parameter yielded the most favorable outcomes, with the highest recorded electrical conductivity. Additionally, the temperature measurement for the same parameter was the highest recorded, indicating that all particles were sufficiently melted to spread effectively upon impact with on the substrate or on the previously deposited coating, resulting in optimal bonding.