Interfacial bonding of low-pressure plasma-sprayed Fe-based amorphous coating on 8090 Al–Li alloy

ABSTRACT Fe-based amorphous coatings (AMC) are deposited on 8090 Al–Li alloy using low-pressure plasma spraying. Coating’s microstructure and interfacial characteristics are investigated. The coating is mainly amorphous in structure. Some crystalline phases were observed between the two splats. The corrosion current density of this coating is two orders of magnitude less compared to 8090. The coating has high density as the average porosity is less than 0.5%. Because of partial melting and quick cooling of the 8090 alloy in the process of molten droplets deposition, there is an amorphous transition zone formed at the interface of AMC/8090 Al–Li alloy, which indicates localized metallurgical bonding. In electrochemical testing, the coating shows an obvious passivation tendency, and crystallization between splats is the main cause of corrosion. Owing to the low oxygen content, the coating exhibits excellent wear resistance.