Experimental determination of the features of propagation the second kind combustion waves in condensed matter using the example of Ti–C<sub>2</sub>H<sub>2</sub>O<sub>4</sub

For the first time, an experimental study was conducted on the propagation features of 2nd kind combustion waves using the Ti-C2H2O4 system as an example. SH-synthesis temperatures, velocities, thermal effects, combustion limits, phase and chemical composition of products are determined. The temperature and depth of transformations at the combustion surface were calculated based on the obtained data. It was discovered that a mixture of titanium and oxalic acid can combust over a wide range of component concentrations: from 2 to 19 moles of titanium per mole of acid. Two modes of combustion waves of the 2nd kind have been identified: with a titanium content of 2 to 4 mol per mole of oxalic acid - discrete layer-by-layer, and with a titanium content >4 mol – frontal. In the entire series of experiments carried out with single-phase products, the corresponding composition of the initial mixtures was only 5Ti + C2H2O4 and 6Ti + C2H2O4. The absence of titanium oxalates of the type TiC2O4 and Ti2(C2O4)3 in the products was shown. The possibility of carrying out the SH-synthesis under conditions where the rates, combustion temperatures and thermal effects of the reaction are not symbatic in their concentration dependence has been experimentally confirmed.