Ultrasonically mixed Al-7075 + x wt% of α-Al2O3 (x: 0, 0.5, 1.5 and 2.5) powders were used to synthesize nanocomposites via powder metallurgy route. Thereafter, heat treatment was carried out on a group of samples at solutionized and T6 conditions. The electrochemical corrosion test was performed in 3.5% NaCl solution. From the microstructural analysis, it was found that the nanoparticles were uniformly distributed by the ultrasonication technique. Electrochemical results showed that the solutionized samples possess excellent corrosion resistance as compared to sintered and T6 samples. Simultaneously, the reinforced α-Al2O3 nanoparticles have also influenced the corrosion resistance property of the nanocomposites. Corrosion rate of the Al-7075 alloy was significantly improved by 85% after reinforcing 0.5 wt% of nanoparticles. On subsequent incorporation of nanoparticles, the corrosion rate was found to be increased. Moreover, at 2.5 wt% of nanoparticles addition, the corrosion resistance becomes inferior than that of Al-7075 alloy. Microstructural analysis of the corroded samples is in well accordance with the electrochemical results obtained for all the samples.