ELECTROCHEMICAL BEHAVIOR OF ALUMINUM IN AQUEOUS SOLUTIONS CONTAINING NITRATE AND CHLORIDE IONS AND RARE-EARTH METALS
Rubrics: 2. CHEMICAL TECHNOLOGY
Authors:
1.
Kazan National Research Technological University
2.
Kazan National Research Technological University
3.
KNITU
4.
Kazan National Research Technological University
Type:
Article
Pages:
from 99
to 105
Status:
Published
Received:
03.02.2026
Accepted:
16.03.2026
Published:
05.04.2026
Language:
Russian
Keywords:
ALUMINUM, ANODIC DISSOLUTION, CYCLIC VOLTAMMOGRAM, NITRATE IONS, CHLORIDE IONS, LANTHANUM (III), DYSPROSIUM (III), NEODYMIUM (III), ZIRCONIUM (IV), MAGNESIUM (II)
Abstract:
The electrochemical behavior of A5 aluminum (99.5%) in a 0.5 M NaCl solution in the presence of nitrate ions and zirconium(IV), magnesium(II), disprosium(III), neodymium(III), and lanthanum(III) at potential sweep rates of 1 and 10 mV/s. The anodic polarization curves of the studied solutions resemble those of pure NaCl solution observed at high concentrations of 0.5-1.0 M. The introduction of both lanthanum nitrate and magnesium nitrate into the electrolyte leads to a shift of the aluminum corrosion potential toward positive values by 30-90 mV, as well as shifts in the passivation and breakdown potentials. The difference between the passivation and breakdown potentials is 20-40 mV at all scan rates. The introduction of these compounds into the electrolyte increases the breakdown time of the oxide film on aluminum, to a greater extent when Mg(NO3)3.6H2O is introduced into the solution. In a solution containing magnesium nitrate hexahydrate, after overcoming the oxide barrier at a scan rate of 10 mV/s, an increase in the dissolution rate of aluminum was observed, which was not observed at other scan rates. It can be concluded that the dissolution process of the aluminum electrode proceeds at a higher rate at 10 mV/s. On the cyclic polarization curves of aluminum in a solution (0.007 M La3+ + 0.045 M Zr4+ + 0.5 M NaCl), a region of active-passive metal dissolution and possible active oxygen evolution is detected. At a scan rate of 50 mV/s, a longer interval of current fluctuations was observed. The calculated charge density characterizing this process is 7.82 μC/cm2. The introduction of magnesium nitrate into the electrolyte causes the current fluctuations to cease. This effect can be explained by the inhibition of the pitting formation process by nitrate ions.
The electrochemical behavior of A5 aluminum (99.5%) in a 0.5 M NaCl solution in the presence of nitrate ions and zirconium(IV), magnesium(II), disprosium(III), neodymium(III), and lanthanum(III) at potential sweep rates of 1 and 10 mV/s. The anodic polarization curves of the studied solutions resemble those of pure NaCl solution observed at high concentrations of 0.5-1.0 M. The introduction of both lanthanum nitrate and magnesium nitrate into the electrolyte leads to a shift of the aluminum corrosion potential toward positive values by 30-90 mV, as well as shifts in the passivation and breakdown potentials. The difference between the passivation and breakdown potentials is 20-40 mV at all scan rates. The introduction of these compounds into the electrolyte increases the breakdown time of the oxide film on aluminum, to a greater extent when Mg(NO3)3.6H2O is introduced into the solution. In a solution containing magnesium nitrate hexahydrate, after overcoming the oxide barrier at a scan rate of 10 mV/s, an increase in the dissolution rate of aluminum was observed, which was not observed at other scan rates. It can be concluded that the dissolution process of the aluminum electrode proceeds at a higher rate at 10 mV/s. On the cyclic polarization curves of aluminum in a solution (0.007 M La3+ + 0.045 M Zr4+ + 0.5 M NaCl), a region of active-passive metal dissolution and possible active oxygen evolution is detected. At a scan rate of 50 mV/s, a longer interval of current fluctuations was observed. The calculated charge density characterizing this process is 7.82 μC/cm2. The introduction of magnesium nitrate into the electrolyte causes the current fluctuations to cease. This effect can be explained by the inhibition of the pitting formation process by nitrate ions.
Keywords:
ALUMINUM, ANODIC DISSOLUTION, CYCLIC VOLTAMMOGRAM, NITRATE IONS, CHLORIDE IONS, LANTHANUM (III), DYSPROSIUM (III), NEODYMIUM (III), ZIRCONIUM (IV), MAGNESIUM (II)
ALUMINUM, ANODIC DISSOLUTION, CYCLIC VOLTAMMOGRAM, NITRATE IONS, CHLORIDE IONS, LANTHANUM (III), DYSPROSIUM (III), NEODYMIUM (III), ZIRCONIUM (IV), MAGNESIUM (II)
