Electrochemical Synthesis of Magnesium Hexaboride by Molten Salt Technique

Abstract

The present work reports electrochemical synthesis of MgB6 from molten salts using the precursor consists of LiF–B2O3–MgCl2. An attempt has been made to synthesize metastable phase MgB6 crystal by electrolysis method. DTA/TGA studies were made to determine the eutectic point of the melt and it was found to be around 900°C. The electrolysis was performed at 900°C under argon atmosphere, at current density of 1.5 A/cm2. The electrodeposited crystals were examined using XRD, SEM, and XPS. From the above studies, the electrochemical synthesis method for hypothetical MgB6 from chloro-oxy-fluoride molten salt system is provided. Mechanism for the formation of magnesium hexaboride is discussed.

Simple, Green, and High‐Yield Production of Boron‐Based Nanostructures with Diverse Morphologies by Dissolution and Recrystallization of Layered Magnesium Diboride Crystals in Water

“…The FTIR spectrum of the standard MgB 2 powder also shows a weak band at =668.14 cm −1 , which is indicative of the presence of the B−B bond . The weak band at =1635.45 cm −1 denotes the presence of the Mg−B bond . The bands at =3628.04 and 3710.38 cm −1 correspond to the stretching vibrations of O−H derived from water .…”

“…The bands located at <1000 cm −1 agree well with the modes of β‐rhombohedral boron, as shown by Sundar et al., and the A 2u mode of MgB 2 appears at ≈405 cm −1 (see Figure S11 g). The bands at >1000 cm −1 for the filtrate samples at different aging times indicate the presence of the Mg−B, B−B, B−OH, B−O, B−H, B−H−B, and O−H bonds . The presence of hydrides, oxides, and hydroxide functional groups on the standard MgB 2 powder sample is attributed to its hygroscopic nature.…”

“…The weak band at =1635.45 cm −1 denotes the presence of the Mg−B bond . The bands at =3628.04 and 3710.38 cm −1 correspond to the stretching vibrations of O−H derived from water . The bands at =982.77, 1456.68, and 1635.45 cm −1 correspond to multiples of the absorption band at =485 cm −1 , which suggests native MgB 2 , as shown by Sundar et al .…”

“…[69] The weak band at ñ = 1635.45 cm À1 denotes the presenceo ft he MgÀBb ond. [70] The bandsa tñ = 3628.04 and 3710.38 cm À1 correspond to the stretching vibrations of OÀHd erived from water. [70,71] The bands at ñ = 982.77, 1456.68, and 1635.45cm À1 correspond to multiples of the absorption band at ñ = 485 cm À1 ,w hich suggests native MgB 2 ,a ss hown by Sundar et al [72] The band at ñ = 982.77cm À1 can also be attributed to the in-plane bending and out-of-plane bending of the BÀOÀHb ond.…”

“…The bands at ñ > 1000 cm À1 for the filtrate samples at different aging times indicate the presence of the MgÀB, BÀB, BÀOH, BÀO, BÀH, BÀHÀB, and OÀHb onds. [69][70][71][74][75][76][77] The presence of hydrides, oxides, and hydroxide functional groups on the standard MgB 2 powder sample is attributed to its hygroscopic nature.H owever,t hese functional groups are more pronounced in the spectrao ft he filtrate than in the spectrum of the standard MgB 2 powder (see Figure 7b). This observation suggestst hat these functional groups are likely attained due to the chemical reaction between MgB 2 and water,w hich is supported by the GC-MS results (as mentioned above).…”