The Influence of Sodium Molybdate on the Rate of Corrosion of Aluminum in Phosphoric(V) Acid

Abstract:

Corrosion rates of aluminum in phosphoric (V) acid solutions were determined gravimetrically in a presence of sodium molybdate which acts as an inhibitor. Inhibition efficiencies were calculated. The most effective corrosion inhibition was observed for 0.5 M H₃PO₄ and 100 mM of Na₂MoO₄. Since insoluble corrosion products precipitated onto specimens and influenced the determined corrosion rates, an analysis of a morphology of the specimens was performed by using a scanning electron microscope. The corrosion products are composed of Mo, P, Al and O. An Mo/P atomic ratio varied between 0.8 and 1.6 depending on the concentrations of phosphoric (V) acid and sodium molybdate. For three concentrations of H₃PO₄, the concentration ranges of sodium molybdate, where the gravimetric method may be applied were determined.

• Periodical: Materials Science Forum (Volume 844)
• Pages: 31-37
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.844.31
• Online since: March 2016
• Authors: Przemyslaw Kwolek*, Kamil Dychtoń, Justyna Szydełko, Andrzej Gradzik, Marcin Drajewicz, Jan Sieniawski

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