Cold spray metallization of polymer substrates: Process fundamentals, modeling, and application advances

The metallization of polymer substrates is a critical enabling technology for extending the functionality of lightweight polymers and polymer matrix composites in electronics, biomedical devices, aerospace, energy systems, and emerging engineering applications. However, conventional metallization techniques are often limited by thermal sensitivity, poor interfacial adhesion, restricted scalability, and environmental concerns when applied to polymeric materials. These challenges have driven growing interest in cold spray as a low-temperature, solid-state deposition process that can overcome fundamental incompatibility between metals and polymers although preserving substrate integrity. This review critically reports recent progress in cold spray metallization of polymers, with an emphasis on process fundamentals, numerical modeling, materials design, and application-driven developments. Computational approaches (including CFD, smoothed particle hydrodynamics (SPH), and coupled thermo-mechanical finite element modeling) are reviewed for their role in elucidating particle–polymer interaction mechanisms such as impact-induced deformation, heat generation, interfacial stress evolution, and localized bonding phenomena. Advances in cold spray process variants, surface activation strategies, composite and additive-assisted feedstocks, and integration with additive manufacturing are discussed in the context of expanding the processing window and enabling tailored interface engineering. The review further surveys demonstrated applications in electronics and Electro-Magnetic Interference (EMI) shielding, biomedical coatings, aerospace and energy systems, and emerging sectors requiring scalable, multifunctional polymer–metal systems. Despite significant progress, challenges related to adhesion durability, process reproducibility, scalability, sustainability, and predictive modeling remain inadequately addressed. Addressing these issues will require coordinated advances in experimental characterization, process control, materials design, and multiscale simulation. Overall, cold spray metallization is positioned as a robust and versatile platform for next-generation polymer surface functionalization and hybrid manufacturing.