Effects of interface microstructure on adhesion of polyetheretherketone metallized by titanium cold spray

Titanium powders were cold sprayed onto polyetheretherketone (PEEK) to investigate the effects of interface microstructure on bonding. Process guidelines to achieve adherent metallic deposits via cold spray onto thermoplastics are scarce, and mechanisms for metal adhesion onto thermoplastic substrates are unclear. The formation of a transition layer where deposition changes from metal-on-polymer to metal-on-metal deposition can promote adhesion but requires a clearer understanding. The microstructural features of such transition layers provide insights into mechanisms that promote coating adhesion. Select features, including developed interfacial area ratio and gradation of thermal residual stress, correlated to adhesive strength values. The understanding of interlocking mesoscale features formed during cold spray informs the parameter selection for depositing metals onto thermoplastics with strong adhesion.

Automated summary

Titanium powders were cold sprayed onto polyetheretherketone (PEEK) to investigate the effects of interface microstructure on bonding. The study found that the formation of a transition layer between the metal and polymer deposition can promote adhesion. Microstructural features, such as interfacial area ratio and thermal residual stress, were found to be correlated with adhesive strength values. Understanding these mesoscale features can inform the parameter selection for cold spraying metals onto thermoplastics with strong adhesion.