Ceftriaxone as an Inhibitor for Corrosion of Al in Formic Acid Solutions

The inhibiting effect of ceftriaxone on the corrosion of Al in HCOOH solution was studied by means of weight loss, thermometry, hydrogen evolution and potentiodynamic polarization techniques, complemented with surface examination using scanning electron microscopy (SEM). The obtained results showed that ceftriaxone are excellent inhibitor in HCOOH solution. The inhibition efficiency increases with inhibitor concentration. Polarization curves indicate that ceftriaxone was acted as a mixed-type inhibitor. The adsorption of the inhibitor on Al surface was found to obey Langmuir isotherm and showed a physisorption mechanism. The thermodynamic activation and adsorption parameters were calculated and discussed. Keywords: Ceftriaxone, aluminum, corrosion inhibitor, potentiodynamic polarization, adsorption, gravimetry and gasometr

Oxide Film Destruction on Al-Mg Alloys in HCl Solutions

Open circuit potential technique is used to follow the oxide film destruction of three of Al-Mg alloys in HCl solutions of varying concentrations.  Dissolution of the passive film on pare metal surface takes place in two distinct steps indicating that the film is composed mainly of a barrier layer of Al2O3 adjacent to the metal surface and an outer porous modification on the top of the first one. The rates of oxide film destruction and/or dissolution (δ1¯ and δ2¯) follow a direct logarithmic law. The extent of oxide film destruction and metal dissolution were found to increase with increasing the acid concentration and the percent of Mg content in the alloy sample