Formation of Corrosion-Resistant Films on Al–Zn–Mg Alloy by Steam Coating Using Acidic Zn(NO3)2 Aqueous Solutions
2018 Volume 59 Issue 7 Pages 1166-1172
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2018 Volume 59 Issue 7 Pages 1166-1172
Corrosion-resistant films were fabricated on Al–Zn–Mg alloy by steam coating using an acidic aqueous solution of Zn(NO3)2 at different concentrations. X-ray diffraction patterns and Fourier transform-infrared spectrometer spectra demonstrated that nitrate-type Zn–Al layered double hydroxide (LDH) and ZnO films were formed on the Al–Zn–Mg surface by steam coating at temperatures of 373, 433, and 473 K, using Zn(NO3)2 aqueous solution at 1000 mM. At 513 K, γ-AlO(OH) films were formed on the Al–Zn–Mg surface by steam coating using 1 to 100 mM Zn(NO3)2 aqueous solution. The corrosion resistance of the films was investigated by potentiodynamic polarization curve measurements, which revealed that the γ-AlO(OH) films prepared by steam coating at 513 K using 1 mM of Zn(NO3)2 aqueous solution was the most effective treatment for suppression of pitting corrosion and anodic current density.
This Paper was Originally Published in Japanese in J. JILM 68 (2018) 194–200.
