Electrodeposition of Al, Mn, and Al–Mn Alloy on aluminum electrodes from molten salt (AlCl3–NaCl–KCl)

Abstract

Electrochemical deposition of aluminum and manganese from basic and acidic molten AlCl 3 -NaCl-KCl mixture on an aluminum electrode at 180°C was studied by the methods of voltammetry, and potential and current transient. The deposition of aluminum was found to proceed via a nucleation/growth mechanism in basic melt, while the deposition of manganese was found to be diffusion controlled in basic melt. The diffusion coefficient of Mn 2? ions in basic melt, as derived by voltammetry was in agreement with the deductions of transient methods. Analysis of the chronoamperograms indicates that the deposition of manganese on Al was controlled by 3D diffusion controlled nucleation and growth. The processes are manifested as peaks on a decaying chronoamperogram. Non-linear fitting methods were applied to obtain the kinetic parameters from theoretical formulae proposed to describe this system. It is also found that under more cathodic potentials, the saturation number density of the manganese nuclei and also the efficiency of use of the available surface nucleation sites increased.

Study on the Cathodic Behavior of Impurities in the Process of Aluminum Extraction by Soluble Anode Electrolysis

“…The mass-based AlCl 3 :NaCl:KCl ratio of the molten salt electrolyte was 66:20:14 and this mixture had a melting point of 115 °C. 27,28 Electrolysis experiments were carried out in a glass beaker sealed with a lid and placed on an electric heating mantle. Prior to electrolysis, the dry AlCl 3 , NaCl and KCl were transferred to this beaker, mixed uniformly and heated at 170 °C to melt the mixture.…”

Production of Al–Mn/WC Composite Coatings with Electrodeposition in AlCl3–NaCl–KCl–MnCl2 Molten Salts

“…molten salts [20]. Ting-ting Cai [27] obtained good quality Al-Mn coatings with electrodeposition in an AlCl3-NaCl-KCl-MnCl2 (0.5-2.0 wt.%) melt at 200-220 °C under cathode current densities of 26.7-48.0 mA/cm 2 .…”

“…Amorphous Al-Mn alloy coatings can be prepared using both molten salt electrodeposition [19][20][21][22] and room-temperature ionic solution electrodeposition [23][24][25]. Since room-temperature ionic solutions are highly volatile, expensive [24], mostly toxic and poorly biodegradable, and the synthesis of ionic liquids includes several steps involving highly toxic reagents [26], it is more advantageous to prepare Al-Mn alloys with electrodeposition in low-temperature inorganic molten salts.…”

“…Since room-temperature ionic solutions are highly volatile, expensive [24], mostly toxic and poorly biodegradable, and the synthesis of ionic liquids includes several steps involving highly toxic reagents [26], it is more advantageous to prepare Al-Mn alloys with electrodeposition in low-temperature inorganic molten salts. As an example, M. Jafarian et al electrodeposited Al, Mn and Al-Mn alloys on aluminum electrodes in AlCl 3 -NaCl-KCl molten salts [20]. Ting-ting Cai [27] obtained good quality Al-Mn coatings with electrodeposition in an AlCl 3 -NaCl-KCl-MnCl 2 (0.5-2.0 wt.%) melt at 200-220 Our group has produced Al/TiC nanocomposite coatings with electrodeposition in AlCl 3 -NaCl-KCl molten salts with the addition of TiC nanoparticles [28].…”