Microstructure evolution and corrosion resistance of multi interfaces Al-TiAlN nanocomposite films on AZ91D magnesium alloy

Multi interfaces Al-TiAlN nanocomposite films were deposited on AZ91D magnesium alloy with ion source hybrid magnetron sputtering. Relationship between microstructure evolution and corrosion resistance of the films was investigated. The results show that the column structure is interrupted by multi interfaces. The nanocomposite films are consisted of nanocrystal TiN and amorphous AlN phase. The highest hardness of 31.3 GPa and lowest corrosion current density of 9.37 × 10−8 A/cm2 can be obtained by tuning the interface period. The deflection effect of multi interfaces is the key for the improved corrosion resistance, and the failure mechanism is related to pitting and filiform corrosion.