Abstract―: Features of the application of the method of spark plasma sintering, as one of the most effective and promising for the manufacture of super-refractory oxygen-free ceramics, have been studied for the reactive consolidation of highly dispersed powder Ta2O5–HfO2–C with a carbon deficiency in comparison with that necessary for the synthesis of metal monocarbides. The initial powder has been obtained by the sol-gel method with a calculated ratio n(Ta) : n(Hf) = 9 : 1, confirmed experimentally using the EDX method. Spark plasma sintering experiments of the resulting system have been carried out in a dynamic vacuum at a pressure of 25 MPa and temperatures of 1600 and 1700°C (higher temperatures led to the outflow of molten oxides from the molds before the beginning of carbothermal synthesis of TaC–HfC). The presence of tantalum subcarbide Ta2C in the obtained ceramic is more advantageous than the oxide impurities and the formation of which under the selected conditions has been predicted by thermodynamic calculations. Its absence can be explained by the fact that equilibrium is not achieved when heating, holding, and cooling the sample. © 2021, Pleiades Publishing, Ltd.

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