Analysis of nitrogen ion implantation on the corrosion resistance and mechanical properties of aluminum alloy 7075

Abstract

The present work reports the effect of nitrogen ion implantation on aluminum alloy 7075. The microhardness, corrosion resistance, and surface nanostructure were investigated. The implantation was carried out at energy 60 keV with the ion doses used were 1.70 × 1017 ion/cm2, 1.86 × 1017 ion/cm2, 2.02 × 1017 ion/cm2, 2.17 × 1017 ion/cm2, and 2.33 × 1017 ion/cm2. The microhardness test was performed to study the hardness of the implanted layer which was characterized by X-ray Diffraction (XRD). The potentiodynamic corrosion test was performed in a 0.5 mol/l NaCl solution. The surface nanostructure was investigated by atomic force microscopy (AFM) to study the surface roughness after implantation. The results showed that the microhardness after implantation at 2.17 × 1017 ion/cm2 increased by 90.81%. The increase was attributed to the formation of the AlN phase. The AlN phase was confirmed at 2-theta peaks of 39.53°, 45.84°, 66.90°, and 80.54°. The corrosion test showed the improvement of corrosion resistance by the decrease of corrosion rate from 4.49 mpy to 1.43 mpy. The atomic force microscopy showed the arithmetical mean height (Sa) value was 37.5 nm and the root means square (Sq) value was 47.6 nm. The ion implantation induced the change of material surface due to the penetration of nitrogen ion into the material.