Gravimetric (Corrosion) Study of Carbonaceous Agro-Waste Inhibitor on the Al-Fe-Si alloy (AA8011) in aggressive Nitric (NO3 -) Environment

Abstract The inhibition potential and adsorption properties of agro-waste eggshell (EGS) product on Al-Fe-Si alloy in 0.5 M HNO3 was examined in this novel work. The gravimetric weight-loss measurement was utilized to check the rate of corrosion attack in reference to the time of immersion and the potency of the EGS inhibitor. In this work, the mechanism of the inhibitor adsorption on the AA8011 alloy surface was as well checked to understand the degree of the adherence of the adsorbate to the surface of the metal. The results of the weight loss analysis revealed a reduction in the weight loss and the rate of corrosion in the presence of the green inhibitor. The efficiency of the EGS inhibitor increases with percentage rise in EGS content but decline with time progression, however, the 2 g EGS content maintains good efficiency of about 71.591% at the end of 168 hours. The best regression coefficient of R2 = 0.99088 was achieved from the Langmuir isotherm model and physical adsorption was confirmed from the evaluation of the adsorption free energy (ΔG°ads).