Reconstructed oxide scale driving fracture behavior to improve cold spray bonding

Cold spraying is a promising technology for biomedical and aerospace applications, yet weak inter-particle bonding remains a critical limitation to coating quality. This study introduces a novel approach to enhance interfacial bonding by reconstructing the oxide scale on titanium alloy powders. The reconstructed oxide scale features a loose and more friable structure that facilitates controlled fracture during particle impact, exposing more fresh metallic surfaces and enabling more metallurgical bonding. AC-STEM and interfacial analyses reveal that this reconstructed oxide scale significantly reduces the barrier effect of surface oxides, promoting stronger inter-particle bonding. Bond strength tests confirm substantial improvements in coating performance, demonstrating the potential of oxide scale reconstruction as an innovative strategy to optimize cold-sprayed coatings. These findings offer valuable insights into surface engineering for enhancing interfacial properties and advancing cold spray technology.