Electrolytic Deposition and Diffusion of Lithium onto Magnesium-9 Wt Pct Yttrium Bulk Alloy in Low-Temperature Molten Salt of Lithium Chloride and Potassium Chloride

Abstract

The electrolytic deposition and diffusion of lithium onto bulk magnesium-9 wt pct yttrium alloy cathode in molten salt of 47 wt pct lithium chloride and 53 wt pct potassium chloride at 693 K were investigated. Results show that magnesium-yttrium-lithium ternary alloys are formed on the surface of the cathodes, and a penetration depth of 642 lm is acquired after 2 hours of electrolysis at the cathodic current density of 0.06 AAEcm À2 . The diffusion of lithium results in a great amount of precipitates in the lithium containing layer. These precipitates are the compound of Mg 41 Y 5 , which arrange along the grain boundaries and hinder the diffusion of lithium, and solid solution of yttrium in magnesium. The grain boundaries and the twins of the magnesium-9 wt pct yttrium substrate also have negative effects on the diffusion of lithium.

Microstructures and Mechanical Properties of As-Cast and Hot-Rolled Mg-8.43Li-0.353Ymm (Y-riched mischmetch) Alloy

“…[2,3] Nowadays, Mg-Li alloys are still drawing increasing academic and experimental interests for their good performances and potential use as components of automobiles and portable electronic devices. Recently, interests have focused on various aspects, such as preparing Mg-Li alloys by electrolysis in molten salt [4][5][6][7][8][9][10][11][12][13][14] and noncrystalline bulk Mg-Li alloys by rapid quenching, [15] developing new Mg-Li alloys through ab initio calculations, [16][17][18][19] characterizing Mg-Li alloys with the electron backscatter diffraction (EBSD) method, [20][21][22][23] improving mechanical properties via using severe plastic deformation (SPD) such as equal channel angle extrusion (ECAE), [24,25] among others.…”

Effect of Y on microstructure and mechanical properties of duplex Mg–7Li alloys

“…As the solidification begins, there is a large decrease of Y solubility from the melts to ␣ and ␤ phases in the alloys, and this decrease leads to the abundance of Y atoms and results in the precipitates of Y element. It has been reported when Li atoms deposit onto the Mg-9Y alloy cathode of the electrolysis unit, Li diffuses into the cathode and leads to a Yenriched ␣-Mg phase in the Mg-9Y alloy [21]. It is believed to be mainly ascribed to the low solubility of Y in the ␤-Li matrix [21].…”

“…It has been reported when Li atoms deposit onto the Mg-9Y alloy cathode of the electrolysis unit, Li diffuses into the cathode and leads to a Yenriched ␣-Mg phase in the Mg-9Y alloy [21]. It is believed to be mainly ascribed to the low solubility of Y in the ␤-Li matrix [21].…”