Structural and electrochemical characterization of the Ca₅₀Mg₂₀Cu₂₅Zn₅ amorphous alloy

The quaternary Ca₅₀Mg₂₀Cu₂₅Zn₅ metallic glass in the form of ribbons and plates was successfully fabricated by melt-spinning and copper-mold casting. The structure characterization of the alloy in as-cast state was performed by using X-ray diffraction method. The Reverse Monte Carlo modeling was carried out to obtain structural model of the alloy in the form of ribbon. Moreover, the corrosion behavior of glassy plates was studied by electrochemical measurements and immersion tests in 1, 2 and 3.5% NaCl solution (pH = 5.4) at room temperature. As suspected the lowest corrosion activity of the alloy was observed in 1% NaCl solution. The post-corrosion tests were conducted by scanning electron microscopy and energy-dispersive X-ray spectroscopy to examine the corrosion products and chemical composition of the corroded surfaces. The XPS measurements were used to better understand corrosion behavior of the alloy after immersion during the open-circuit conditions. The corrosion surface products were identified to be CaO, MgO, Mg(OH)₂ and CaCO₃ components. The ZnO and CuO compounds were formed on the surface of glassy samples.