Синтез композитов на основе титана в режиме горения
| Parent link: | Химическая физика и мезоскопия: научное издание.— , 2000- Т. 19, № 4.— 2017.— [С. 524-537] |
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| Summary: | Заглавие с экрана В настоящей работе реализован процесс синтеза композита в системе Ti-C с избытком титана и обнаружено, что в условиях послойного распространения реакции всегда образуется нестехиометрический карбид титана. На основе классических представлений теории твердофазного горения с суммарной реакцией численно реализована модель, которая, в отличие от известных моделей, учитывает нестехиометрический состав исходной смеси, зависимость свойств от состава и стадию поджигания воспламенителя. Получено частичное соответствие данным эксперимента, что говорит о необходимости учета при моделировании большего набора физических и химических явлений. В том числе, схема реакции и набор соответствующих кинетических уравнений должны учитывать формирование неравновесных фаз, нестехиометрического карбида, раствора углерода в титане. One of the methods of composite manufacturing based on titanium with inclusions of carbides borides and silicides is self-propagating high-temperature synthesis (SHS) or combustion synthesis. However, this process is nonequilibrium process and it is not possible to predict the composition of the synthesis product. One of the most studied systems is the "titanium-carbon" system. In recent years,interest in this system is associated with the unique properties of carbides and with the possibility of obtaining nonequilibrium ordered structures in nonstoichiometric mixtures. There are numerous experimental data on both the solid-phase mechanism of synthesis in this system and the mechanism in which capillary spreading plays a significant role. Despite extensive experimental studies of the mechanism of product formation in this system, a large role is assigned to mathematical modeling in macrokinetics. However, there is still no single point of view on the need to take into account in the models certain physical phenomena. Different ideas underlying the well-known combustion models suggests that much is still unclear in this area. In the present work, the synthesis of a composite in a Ti-C system with an excess of titanium is considered. It is found that under non-stochastic propagation conditions, non-stoichiometric titanium carbide is always formed. A model based on the classical concepts of the solid-state combustion theory with the total reaction is numerically investigated. The model proposed here differs from the known models by taking into account the non-stoichiometric composition of the initial mixture, the dependence of the properties on the composition and the stage of ignition of the igniter. Only partial correspondence theoretical calculations to experimental data is obtained, which suggests the need to take into account a larger set of physical and chemical phenomena in modeling. The reaction scheme and the set of appropriate kinetic equations should take into account the formation of nonequilibrium phases, nonstoichiometric carbide, carbon solution in titanium. This is the subject of further research. Режим доступа: по договору с организацией-держателем ресурса |
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2017
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| Online Access: | http://elibrary.ru/item.asp?id=32341276 |
| Format: | Electronic Book Chapter |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=658048 |