Interfacial bonding mechanism and properties of HVOF-sprayed Fe-based amorphous coatings on LA141 magnesium alloy substrate

Due to poor corrosion and wear resistance, Mg-Li alloys often experience the premature failure during their service. In order to improve the corrosion and wear resistance of Mg-Li alloys, Fe-based amorphous coatings were firstly prepared on the LA141 magnesium alloy substrate by high velocity oxygen-fuel spraying technology (HVOF) in this study. It is noticed that by introducing the Ni60 interlayer with the thickness of 150 mu m, the bonding strength of the Fe-based amorphous coating on LA141 alloy substrate can reach 56.9 MPa, which is currently the highest value of Fe-based amorphous coatings on magnesium alloys reported so far. It is found that the improvement of bonding strength is attributed to the localized metallurgical bonding at the interfaces of Fe-based amorphous coating/Ni60 and Ni60/LA141 and the compactness of Fe-based amorphous coatings. Moreover, the corrosion and wear resistance of the LA141 magnesium alloy with the Fe-based amorphous coatings are 34 times and 170 times higher than those of the bare LA141 magnesium alloy substrate, respectively. Finally, the failure mechanisms of the Fe-based amorphous coatings during tension and wear are discussed. This study can provide an alternative method for the surface protection of Mg-Li alloys.