Optimization and characterization of Cu-Zn-Al₂O₃ cold spray coating on PEEK

Depositing metallic coatings on polymer substrates using the low-pressure cold spray has recently presented significant challenges, primarily due to poor adhesion and low deposition efficiency. This study employs a hybrid approach, combining numerical and experimental analyses, to coat PEEK with Cu-Zn-Al₂O₃ coating using a low-pressure cold spray technique. PEEK substrates, known for their lightweight, chemical resistance, and mechanical strength, can be combined with Cu-Zn-Al₂O₃ coatings for advanced applications due to their antimicrobial properties, thermal stability, and surface durability. Particle-laden flow and finite element simulations were employed to optimize the cold spray parameters. The optimized parameters were used to coat PEEK sheets, and the resulting coatings were evaluated for microstructure, phase composition, mechanical properties, surface roughness, and layer thickness. The findings show that combining the particle flow and finite element simulations with experiments is critical for predicting a more reliable deposition window for coating PEEK with Cu-Zn-Al₂O₃ coatings through low-pressure cold spraying. This optimization exercise reduces powder material waste while preventing PEEK damage. The gas temperature is critical for coating deposition efficiency and cohesive strength, with optimal temperatures producing high-quality coating. Dendritic Cu particles combined with spherical Zn particles improve coating deposition efficiency and bonding probability, whereas Al₂O₃ particles increase coating overall hardness while reducing nozzle clogging. The coating layer is dense, well-layered, and exhibits minimal porosity, highlighting the significant role of Zn particles in its formation. The surface roughness of the coating is also influenced by the spray parameters. The scratch tests demonstrated strong adhesion/cohesion of the Cu-Zn-Al₂O₃ coating onto PEEK. This study paves the way for potential new applications of PEEK substrates coated with metallic coatings, expanding its applications in advanced industries.