Conclusions
-
1.
The specific resistance, absolute differential thermo-emf (in the temperature range 20–1000°C), the Hall coefficient, the thermal conductivity, and the microhardness of monolithic specimens of pyrolytic boron carbide with the theoretical density and a compact laminated-acicular structure were measured.
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2.
In the temperature range investigated boron carbide is an impurity semiconductor of the p-type with carrier concentrations of 3.4 · 1020 cm−3, a Hall mobility of 0.13 cm2 /V · sec, and an effective mass m*; m0 = 0.44.
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3.
The energy of activation of the impurity carriers is 0.22 eV; the level of chemical potential is situated in the center of the energy range between the ceiling of the valence zone and the acceptor level.
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4.
p-Conductivity in boron carbide apparently is due to the partial substitution of carbon atoms in the boron carbide of the limiting composition B + C = (B13)C3 by boron atoms with a lower valency.
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Translated from Poroshkovaya Metallurgiya, No. 11(71), pp. 62–68, November, 1968.
The authors would like to express their indebtedness to Yu. D. Kondrashev for his assistance in evaluating the structure of the specimens of pyrolytic boron carbide.
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Neshpor, V.S., Nikitin, V.P. & Rabotnov, V.V. Studying certain electrical and physical properties of pyrolytic boron carbide. Powder Metall Met Ceram 7, 889–894 (1968). https://doi.org/10.1007/BF00780309
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DOI: https://doi.org/10.1007/BF00780309