Insights into Interfacial Bond Strength of Cold Spray-Metallized Polymer Substrates from Single Particle Impact Simulations

Metallization of polymer-based composites is vital for applications in aerospace, automotive, wind energy, and electronics industries, where addressing challenges such as electrical discharge mitigation or surface erosion is crucial. Cold spray is emerging as a cutting-edge technology for polymer metallization, offering a transformative approach to achieving desired material enhancements. This study employs finite element analysis to evaluate the effective bond strength (i.e., pull-out force) between single 20-micron diameter spherical copper (Cu) particles and polyether ether ketone (PEEK) substrates under various cold spray impact conditions. Analysis centers on determining the pull-out force necessary to detach individual Cu particles from the substrate, providing insights into the metallization mechanism. Results reveal that the systems studied reach thermo-mechanical equilibrium within a post-impact timeframe of <10^-7 seconds, with deposition dynamics largely unaffected by impacting particle temperature. Moreover, this study identifies a direct correlation between increasing impact velocity (from 400-700 m/s) and increasing pull-out forces. This study further investigates variation in bond strength due to post-impact substrate heating, showing modest decline in pull-out force with increasing temperature. These findings may be useful in optimizing the overall performance of metalized polymer/composites by cold spray and may also offer insights on thermal-mechanical performance of metallized deposits.