Borides from metallic fluxes

2 Borides from metallic fluxes. The preparation of several binary borides of lanthanides, vanadium, tantalum, chromium has been performed by using aluminium as a flux. Aluminium has been used also as a reactive flux in the preparation of alumino-borides (of Mo, Fe) which are stable in concentrated HC1 solutions. 

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An attractive method to produce single crystals (in the dimension range from pm to several nun) is the high-temperature solution (flux) method, becanse of its simphcity and the low temperature required. The elements are dissolved in the solvent metal (often Al) and subseqnently the solntion is slowly cooled to room temperature. A prerequisite is, of course, that the solubility of the used solvent in the desired boride is insignificant. The solubility of Al in most boron-rich binary borides has been found to be extremely small. Crystals prepared in this manner are suitable for measurement of physical properties, for instance, microhardness, electrical resistivity, and so on. 

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