A versatile route for the convenient synthesis of rare-earth and alkaline-earth hexaborides at mild temperatures

Additive-assisted synthesis of boride, carbide, and nitride micro/nanocrystals

“…All the XRD patterns show the sharp and well-defined peaks, indicating the high crystallinity of the products. The diborides (MB 2 ) show a hexagonal crystal structure and the hexaborides (MB 6 ) exhibit a cubic crystal structure, both of which are in good agreement with the reported literature [26]. No impurity peaks of B, S and related oxides can be detected by XRD patterns.…”

“…The average sizes of TiB 2 , LaB 6 , CeB 6 and EuB 6 nanoparticles are 100 nm, 1 mm, 300 nm and 200 nm respectively. It should be pointed out that the as-prepared MB 6 nanoparticles exhibit regular crystal facets to form a cuboid shape, well consistent with their cubic crystal structure [2,26,36]. Similarly, other borides (ZrB 2 , NbB 2 , PrB 6 , SmB 6 ) have been synthesized by the same method.…”

“…For example, ReB 6 (Re¼La, Ce, Pr, Sm, Nb, Eu) particles were synthesized by the co-reduction of the corresponding rare-earth oxides and H 3 BO 3 with the assistance of Mg and I 2 at 170-400 1C [26]. MN x (M¼Zr, Ti, Al, B) powders were prepared at 250-400 1C via a sulfur-assisted synthesis process with the corresponding elements, NaN 3 and S as the reactants [27].…”

Preparation of LaB₆ Powders via Calciothermic Reduction using Mechanochemistry and Acid Leaching

“…Recently, nanosized (nanocubes and nanorods) or submicron LaB 6 powders have been obtained by using low temperature synthesis in an autoclave and self-propagating high-temperature synthesis (SHS) methods (Ji et al, 2011;Dou et al, 2012). Autoclave systems provide an alternative route for synthesizing LaB 6 at lower temperatures than used in traditional methods (Wang et al, 2010). SHS methods have high reaction speed, simple equipment and low energy consumption but after ignition, the reaction process becomes uncontrolled which results in the occurrence of intermediate phases in the reaction products (Dou et al, 2011).…”

“…Especially, rare-earth metal hexaborides have numerous useful physical and chemical characteristics which make them important to investigate (Post et al, 1956;Futamoto et al, 1980;Otani and Ishizawa, 1996;Balakrishnan et al, 2004;Selvan et al, 2008;Wang et al, 2010;Ji et al, 2011;Brewer et al, 2011;Aprea et al, 2013).…”