Conclusions
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1.
A study was made of the conditions of preparation of barium and calcium hexaborides by the boroncarbide and borothermic techniques and by the reaction of barium carbonate with boron in a vacuum.
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2.
It was established that a barium hexaboride with a composition approaching theoretical can be obtained by the borothermic techniques at a temperature of 1600°C from a charge with a 40% excess of barium oxide. It is more economical to prepare BaB6 by the reaction of barium carbonate with boron in two stages (30 min at 900°C and 60 min at 1500°C).
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3.
The optimum conditions for the preparation of calcium hexaboride by the borothermic and boroncarbide techniques are a temperature of 1600°C and a holding time of 60 min; the charge should contain a 10% excess of calcium oxide.
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4.
The results obtained have been analyzed in terms of the electronic structure of atoms of the alkaline-earth metals and their oxides.
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Literature cited
G. V. Samsonov, L. Ya. Markovskii, A. F. Zhigach, and M. G. Valyashko, Boron, Its Compounds and Alloys [in Russian], Izd-vo AN USSR, Kiev (1960).
G. V. Samsonov, T. I. Serebryakova, and A. S. Bolgar, Zh. Neorgan. Khim.,6, 2244 (1961).
T. N. Nazarchuk, Analysis of Refractory Compounds [in Russian], Moscow (1962).
Thermodynamic Properties of Individual Compounds [in Russian], Vol. 2, Izd-vo AN SSSR, Moscow (1962).
L. Ya. Markovskii and N. V. Vekshina, Zh. Prikl. Khim.,34, No. 2 (1961).
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Translated from Poroshkovaya Metallurgiya, No. 8 (80), pp. 4–9, August, 1969.
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Serebryakova, T.I., Marek, É.V. Conditions of preparation of calcium and barium hexaboride powders. Powder Metall Met Ceram 8, 608–612 (1969). https://doi.org/10.1007/BF00775416
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DOI: https://doi.org/10.1007/BF00775416