2015
Sevastyanov V.G., Simonenko E.P., Gordeev A.N., Simonenko N.P., Kolesnikov A.F., Papynov E.K., Shichalin O.O., Avramenko V.A., Kuznetsov N.T.
Abstract—Ceramic HfB2–SiC samples with a silicon carbide content of 45 vol % have been obtained by sparkplasma sintering, their density and calculated porosity determined, and certain studies performed using IR spectroscopy, XRD, and other methods. The behavior of the HfB2–SiC (45 vol %) material has been studied using the VGU4 highfrequency induction plasmatron with heating by a subsonic flow of dissociated air. It has been shown that the average temperature of the surface of the samples in the process of heating rises up to 2680–2690°C, which is connected with the formation on the surface, which has the temperature of ~1700–1900°C, of local regions with the temperature of 2600–2700°C with gradually expanding areas. The total time during which the average surface temperature is higher than 2000°C is ~30 min. The change in the composition of the gas phase above the sample surface in the course of the experiment was investigated using optical emission spectroscopy. Assumptions, which explain the changes in the concentration of boron and silicon under the action of a highenthalpy flow, have been advanced. The elemental composition and the phase composition have been determined, and the microstructure of the surface and of various cuts of the samples have been studied.
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