Combustion of "gasless" systems is currently described in terms of a theory based on the assumption of a conductive mechanism of heat transfer in the combustion wave [1,2].Among the fundamental principles of this theory are the concept of the existence of combustion limits at a certain small sample diameter and also the concept of a monotonic decrease in the combustion velocity with a decrease in the sample diameter [2,3].However,in an attempt to experimentally determine the critical diameter for samples compacted from titanium-boron and zirconium-boron powder mixtures (typical gasless systems) [4],the dependence of the combustion velocity on the sample diameter turned out to be anomalous (from the standpoint of the modern theory of gasless combustion).It turned out that the combustion velocity was maximal at the minimal sample diameter and the curve of the combustion velocity as a function of the sample diameter has a minimum.The combustion limit was not attained even at a sample diameter of as small as 3X10~(-4) m.Results inconsistent with the principles of the modern theory of gasless combustion were also obtained in study of the combustion of a layer of a titanium-boron powder mixture placed between two quartz plates [5].The combustion velocity increased sevenfold with a decrease in the layer thickness H from 10 to 2 mm and,in the propagation limit (H=0.15 mm),was twice as high as the combustion velocity at H=10 mm.
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