Optimizing Cold Spraying Parameters of Metallic Coatings Deposited Onto Polymer Substrate

Abstract Polymer-based composites offer several advantages, such as high strength-to-weight ratio, exceptional corrosion resistance, and tailored mechanical properties. However, they may also have limitations, such as poor surface finish, low thermal conductivity, and limited wear resistance especially when fabricated through 3D printing technologies. Therefore, through surface metallization, cold spray can overcome these limitations by depositing metallic composite coatings onto polymer-based components. This study investigates the optimization of cold spraying parameters to achieve effective polymer metallization via cold spraying of anti-bacterial coating onto PEEK. A combination of Cu and Al2O3 particles is used in the feedstock to effectively metallize PEEK. The cold spray parameters (such as gas temperature, particle velocity, powder feed rate, scan speed, step size, spray path pattern, and spray distance) are optimized to achieve high-quality metallic coatings using computational fluid dynamics (CFD) simulations that investigate particle flow dynamics. Finite element and smooth particle hydrodynamics simulations are used in a hybrid computational technique to evaluate the impact characteristics of the deposited particles. The optimized parameters are used to make coating samples and evaluate their microstructure, phase composition, and mechanical properties using various analytical tools. A gas pressure of 6 bar and a temperature of 400 °C were identified as optimized conditions for metallizing PEEK. Dendritic Cu particles resulted in shallower penetration depth and less PEEK erosion compared to spherical Cu particles. A dense and defect-free Cu-Al2O3 coating layer with a thickness of ∼ 290 μm. The presence of Al2O3 particles enhanced interfacial bonding and hardness of the coating layer. The results demonstrate ways of achieving effective metallization of polymers through precise control of cold spraying parameters.