Experimental Studies on the Effect of Expired Amiodarone Drug (EAD) as a Corrosion Inhibitor on Mild Steel in 1 M HCl.

In the present investigation, the corrosion tendency of mild steel under acidic pH was studied by employing unused expired amiodarone (EAD) drug as a potential corrosion inhibitor by adopting the weight loss measurement method. The corrosion inhibition efficiency (IE) of the formed protective film (EAD) on the steel surface was analyzed using potentiodynamic polarization and AC-impedance spectroscopy studies. The surface morphology of the mild steel before and after corrosion (in 1.0 M HCl) was analyzed via scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDAX), atomic force microscopy (AFM), and thermodynamic studies. The weight loss measurement under different concentrations of EAD indicated that an excellent inhibition was displayed at a concentration of 0.001 M, and the IE was found to depend on both the concentration and molecular structure of EAD. A potentiodynamic polarization study revealed that EAD predominantly acted as a cathode inhibitor, and electrochemical impedance spectroscopy (EIS) confirmed the adsorption of EAD on the surface of mild steel, which obeyed Temkin's adsorption isotherm model. The calculated thermodynamic parameters revealed that adsorption was spontaneous and exothermic.

Mechanical alloying of Mg0.8-XTi0.2 and study the effect of adding (x = 0.2 wt%) transition metal like Sc, Zr, or Nb on their phase transitions, activation energy, and hydrogen storage properties.

Till now Mg-based alloys have attracted much attention due to the high storage capacity of hydrogen. An effort was made to evaluate the apparent activation energy and electrochemical behavior of transition metals such as scandium (Sc), zirconium (Zr), and niobium (Nb) alloyed with Mg-Ti. Mg0.8Ti0.2, Mg0.6Ti0.2Sc0.2, Mg0.6Ti0.2Zr0.2, and Mg0.6Ti0.2Nb0.2 alloy powders were synthesized using high-energy ball milling. Ballmilled powders were subjected to structural and morphological characterization using X-ray diffraction and scanning electron microscopy respectively. A strong shift in the inter-planar spacing value of milled powders confirmed supersaturated solid solution of Ti and transition metals in Mg. The inter-planar spacing values before and after milling are found to be 0.24 and 0.21 nm, respectively. Mg0.8Ti0.2, Mg0.6Ti0.2Sc0.2, and Mg0.6Ti0.2Zr0.2 alloy powders result in the FCC phase while Mg0.6Ti0.2Nb0.2 powders result in BCC phase, however, the entire powders have an amorphous background. SEM-EDS analysis of the milled powders confirmed the presence of Mg, Ti, Sc, Zr, and Nb elements with a small amount of oxygen. Selected area electron diffraction (SAED) pattern of Mg0.8Ti0.2 alloy powders exhibits a nanocrystalline nature owing to their polycrystalline ring pattern. Exothermic peak broadening increases after the substitution of Nb and Zr in Mg0.8Ti0.2 alloy powder, which exhibits a lower activation energy (188 kJ mol-1) than others. In cyclic voltammetry, a drenched cathodic peak is observed for Mg0.8Ti0.2 at a potential around -0.83 V. In electrochemical impedance spectroscopy, the charge transfer resistance of Mg0.6Ti0.2Sc0.2 is lower than that of Mg0.6Ti0.2Zr0.2 and Mg0.6Ti0.2Nb0.2 alloy but higher than Mg0.8Ti0.2 electrode materials, and charge-discharge studies were done on the developed electrode materials. It shows that Mg0.8Ti0.2 electrode material delivers a maximum discharge capacity of 535 mA h g-1.