Electrochemical Formation and Phase Control of Mg–Cu Alloys

Abstract

Mg–Cu alloys with different phases were electrodeposited in a molten LiCl–KCl eutectic mixture containing a small amount (0.5 mol %) of MgCl2 at 673 K. The electrochemical behavior of the MgII ion and alloy formation processes were studied at inert molybdenum (Mo) and active copper (Cu) electrodes in the molten salts, respectively. Different electrochemical techniques, such as cyclic voltammetry, square‐wave voltammetry, chronoamperometry, and open‐circuit potentiometry were carried out to investigate the electrochemical formation mechanism of Mg–Cu alloys. Three signals, corresponding to the formation of metal Mg and two different Mg–Cu alloy phases, are observed when using cyclic voltammetry, square‐wave voltammetry, and open‐circuit potentiometry. Chronoamperometry studies indicate the different interfacial properties of the magnesium metal versus the Mg–Cu alloys. The results of X‐ray diffraction and scanning electron microscopy show that the MgCu2 and Mg2Cu phases could be obtained at −2.30 and −2.38 V (vs. Pt), respectively.

Electrochemical Deposition of Magnesium on SiC Fibers from the LiCl-KCl-MgCl2Molten Salt

“…1 , B 1 /B 1 and C 1 / C 1 in solid line (obtained with SiC fiber/Cu electrode) should be in accordance with these redox peaks of A 2 /A 2 , B 2 /B 2 and C 2 / C 2 in dashed line (obtained with Cu wire electrode), respectively. These three redox peaks should be corresponding to the deposition and dissolution of the alloys MgCu 2 , Mg 2 Cu and Mg, respectively, according to our former work 20. This experiment indicated that SiC/Cu electrode showed almost the same properties of metal Cu electrode in the electrodeposition processes.…”

“…Electrochemical equipment and techniques.-The molten salt electrodeposition experiments were carried out in an apparatus described in detail in our previous works. 20 The dried LiCl-KCl-MgCl 2 mixture was placed in a high-purity alumina crucible, which was then held in a stainless steel cylindrical cell in an electric furnace. Electrochemical measurements were carried out in the three-electrode configuration.…”

“…The cathodic current wave D 2 appeared at about −2.42 V (vs. Pt) which should correspond to the reduction of Mg 2+ ion according to our former work. 20 An obvious anodic current peak D 2 also appeared at ca. −2.25 V (vs. Pt), which should be attributed to the dissolution of Mg.…”

Electrochemical properties of yttrium on W and Pb electrodes in LiCl–KCl eutectic melts

“…If the relationship of electric quantity (Q) and the square root of time (t 1/2 ) is linear, the electrode reaction is controlled by diffusion of ions to electrode surface. 52 Thus, it demonstrates from Fig. 7b that the reaction of Y(III) on liquid Pb electrode is controlled by diffusion.…”

“…13d ) shows the sample is mainly composed of two phases, Pb and Pb 3 Y. According to Pb–Y phase diagram, 52 there are four Pb–Y intermetallic compounds (Pb 3 Y, Pb 2 Y, Pb 4 Y 5 and Pb 3 Y 5 ). When the extraction was performed on liquid Pb electrode, the amount of Pb is large, thus, the Pb-richest Pb–Y compound Pb 3 Y can be formed.…”