Alexandr G. Merzhanov

Combustion of vanadium-iron alloys in nitrogen

The starting alloys were prepared from specially pure carbonyl iron (99.8% Fe) and electrolytic vanadium VEL-1 (99.8% V) in a vacuum furnace, crushed to a powder with particle size less than 0.14 mm and pressed into pellets with a relative density of 0.48-0.64. The burning of the alloys is described. The nitrogen pressure in the bomb was varied from 1 to 130 atm. In the experiments the burning specimens were frequently quenched in water. The starting material and combustion products were analyzed radiographically and metallographically. The paper discusses effect of iron content of alloy on burning rate and extent of reaction, as well as laws of combustion of alpha- and sigma-ferrovanadium. A review is given of phase transition to sigma-ferrovanadium combustion. A discussion of the results is presented.

Self-cleaning of SHS titanium carbide from impurity oxygen

Analysis of numerous refractory compounds obtained by the SHS method shows that they self-clean from impurities during synthesis of the final products; the content of many gaseous and volatile impurities turns out to be substantially less in the final product than in the original charge. A singly directed experimental investigation of the regularities for self-cleaning from impurity oxygen in SHS systems is reported on in this paper for the example of the simplest system, Ti + C. Titanium brand PTS was used in the tests. The soot traditionally used in the synthesis of TiC by the SHS method was replaced by graphite powder obtained by grinding up rods from spectrally pure graphite with subsequent separation into fractions. The mass content of impurity oxygen in graphite powder is -0.4%, and in titanium powder is (0.4-0.6)%.

Influence of ultrasonic vibrations on the combustion of condensed systems with solid-phase reaction products

It has been shown in the example of the combustion of the Ti-B system that high-frequency mechanical vibrations under the conditions of the limiting action of liquid titanium filtration result in significant increase in the combustion velocity. The influence of ultrasonic vibrations on the formation of the final reaction product is investigated in this paper, with the system Ti-B-Fe selected for the tests.

Self-purifying mechanism from oxygen contaminant during combustion of a mixture of molybdenum and boron powders

Conclusions1.By means of vacuum annealing a study has been made of the combustion wave structure for the Mo+B system. It has been shown that with To<900°K the system burns in accordance with a broad reaction zone model, but with To>900°K it burns in accordance with a narrow reaction zone model.2.A microkinetic model has been suggested for self-purification of MoB products from oxygen contaminant.3.On the basis of experimental results it has been shown that in the initial temperature region, where the Mo+B system burns in accordance with the narrow reaction zone model, self-purification from oxygen contaminant (by evaporation of oxide films) proceeds only in the combustion wave warm-up zone, in other words for Mo+B there is a strong dependence of evaporation rate on the depth of conversion for energy-supporting reactions.

Combustion of condensed substances in a mass force field

Summary1.A description is given of an apparatus for studying the combustion of condensed substances at atmospheric pressure under the action of large mass forces.2.A study has been made of the laws of combustion of polyvinyl nitrate under the action of mass forces (up to 900 g) in two directions (from the combustion products toward the starting material and in the opposite direction).