Corrosion inhibition of aluminum in sodium hydroxide solutions using some inorganic anions

The rates of corrosion of aluminum and hydrogen gas production in sodium hydroxide solutions without and with the additions of chromate, phosphate, and tungstate anions were examined. Potentiometric, weight loss, thermometric, gasometric, galvanostatic polarization, and electrochemical impedance spectroscopy techniques were used. The data show that these anions favored oxide film formation and mitigate hydrogen production. The inhibition efficiency, eta, was calculated and found to depend on the anion-type and concentration, as well as, temperature. The inhibition mechanism is assumed to take place through an adsorption process obeying Temkin's isotherm. The thermodynamic parameters for the adsorption process K-ads and Delta G degrees(ads) are calculated and discussed. The surface examination was investigated using SEM and EDX spectroscopy.

Automated summary

The study examined the rates of corrosion of aluminum and hydrogen gas production in sodium hydroxide solutions with the additions of chromate, phosphate, and tungstate anions. The data showed that these anions promoted oxide film formation and mitigated hydrogen production. The inhibition efficiency, eta, was found to depend on the type and concentration of the anion, as well as temperature. The inhibition mechanism was assumed to occur through an adsorption process following Temkin's isotherm, with thermodynamic parameters such as K-ads and Delta G degrees(ads) calculated and discussed. Surface examination was conducted using SEM and EDX spectroscopy.