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Shape and polarity of thermo-emf signals arising during combustion of Ti–хB mixtures (x = 0.75–5.5) in conditions of quasi-static compression were found to depend on boron content x: emf signal was positive for x ≤ 1, negative for 1.5 ≤ x ≤ 3.0, and short negative for x ≥ 3.5. Generation of positive emf signals was associated with the n-type conductivity of Ti while negative ones, with the p-type conductivity of boron.

Composition/structure of products formed upon frontal combustion of Si powder in gaseous carbon dioxide at P(CO2) = 0.4–5.0 MPa were characterized by chemical analysis, XRD, and SEM/EDS. Combustion products were found to contain SiC, unreacted Si, and SiO2. Our results may turn interesting to those engaged in fabrication of heat-resistant Si–O–C ceramics.

Fine powders of pure Si2N2O were SHS-produced under pressure of nitrogen gas from mixtures doped with FeCl3 · 6H2O, and the influence of process conditions was explored by XRD and SEM/EDS. Pure 2D-nanopowders of Si2N2O were obtained in the presence of 15 × 10–3 M FeCl3 · 6H2O in green 3Si + SiO2 mixture at P(N2) = 5 MPa.

The effect of iron-containing catalysts–FeCl3 · 6H2O, Fe2(C2O4)3 · 5H2O, and Fe(NO3)3 · 9H2O–on phase composition, morphology, and particle size of products formed upon combustion of Si–C mixtures in nitrogen gas. Composition and granulometry of combustion products were found to depend on a type and amount of the above additives to green composition. The results may turn interesting for researchers active in the synthesis of refractory silicon compounds.

Explored was the influence of compacting pressure (P) and green density (ρ) on the properties of Zr-doped mineral-like pyrochlore ceramics Y2(Ti1 – x Zr x )2O7 (x ≤ 0.3) prepared by SHS method. The optimal ρ values that provide minimal porosity and maximal mechanical strength of synthesized ceramics were found. An increase in ρ was found to decrease combustion temperature and increase pyrochlore lattice parameter a. Green density was also found to affect phase composition of the SHS-produced ceramics under study.

Mineral-like Y2(Ti1–x Zr x )2O7 ceramic matrices for immobilization of actinide–Zr–RE-containing high-level nuclear wastes (HLW) were prepared by SHS method. In experiments, HLW were modeled by a mixture of CeO2, La2O3, ZrO2, MnO2, and Fe2O3 powders. An increase in the HLW content of green mixture decreased the amount of Y2(Ti1–x Zr x )2O7 in combustion product and increased that of ZrO2, LaTiO3, and CaTiO3; decreased the fractional substitutionality of Zr for Ti; and increased the product porosity. An increase in combustion temperature and suppression of heat sink during SHS reaction did not diminish markedly the porosity of synthesized ceramics.

SHS reaction in Zn-S powder blends was explored in conditions of quasi-isostatic compression (P = 1–100 MPa) using a specially designed experimental setup. A maximum value of burning velocity U (1 m/s) was attained at P ≈ 32 MPa. A spasmodic pressure change was observed during combustion as well as the generation of voltage pulses with the amplitude 150–200 mV and duration 10–70 s. The amplitude and duration of combustion-induced EMF were found to depend on P.

For the Ti-C system taken as an example, burning velocity U as a function of applied pressure P was found to be bell-shaped with a clearly pronounced maximum (Umax). The ascending branch of the U(P) function was associated with a pressure-induced increase in the thermal conductivity of starting compacts and suppressed expansion of impurity gases. The descending branch was attributed to a decrease in U due to ever increasing thermal conductivity resulting in a gradually growing heat sink from a burning sample. The annealing of starting compacts in vacuum had little or no influence on U but shifted Umax to lower P.

Investigated was the generation of thermal electromotive force (EMF) during combustion of Ti + C powder mixtures under pressure. Comparison between the EMF curves taken for the mixtures under study and a model Ni/Ti/Ni thermocouple has led to a conclusion that the generation of voltage during combustion of Ti + C mixtures can be identified as the thermal EMF arising in different conductor/semiconductor thermocouples formed between Ni electrodes and starting/end compounds, rather than to formation of ionic species as suggested earlier.