Аналіз структурно-хімічного стану формування шару термітного сплаву на сталевій підкладці самопоширюваним високотемпературним синтезом

• Дата: 2023
• Автори: Скідін, І.Е., Бєлов, Б.Ф., Воденнікова, О.С., Воденніков, С.А., Саітгареєв, Л.Н., Бабошко, Д.Ю.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Physico-technological Institute of Metals and Alloys 2023
• Теми: самопоширюваний високотемпературний синтез; алюмотермічні реакції; сформований шар; структурно-хімічний стан; термітний сплав
• Онлайн доступ: https://www.metalsandcasting.com/index.php/mcu/article/view/135
• Назва журналу: Metal and Casting of Ukraine

The structural and chemical state of thermite alloy layer formation on the basis of chromium and on the basis of iron on a steel substrate received by means of self-propagating high-temperature synthesis is analyzed. High-temperature self-propagating synthesis covers a strong exothermic reaction of the mixture, i.e. combustion reaction; the process is characterized by high temperature (≈ 3000 °C) and high rate of propagation of the combustion front (0.5–15 cm/s). As a result of high-temperature self-propagating synthesis, iron is reduced from oxides and the fine components of the charge are melted. Based on the stochastic analysis of the material balance of structural and chemical reactions of the initial components of the charge (steel scale, aluminum powder, carburetor for carburization, iron powder or chromium powder) the mechanism of formation of metal, slag and gas phases under alumina and thermo self-propagating high-temperature synthesis is presented. It is approved that in the process of forming thermite alloy layer on a steel substrate by high-temperature aluminothermy self-propagating synthesis, nonmetallic inclusions, so-called corundum centers, which are the product of the reaction of iron oxide with aluminum, are formed in the structure of the termite alloy, chromium and iron carbides. This statement was confirmed by metallographic studies of samples of termite alloy based on iron and samples of termite alloy based on chromium, which showed that the macrostructure of the formed layer is represented by a ferrite and perlite matrix content, cemented or iron-chromium cementite in the amount of 83.0 % and nonmetallic inclusion in the form of alumina in the amount of 17.0 %. It was found that the microhardness of the samples from the formed layer of thermite alloy obtained from the mixture based on chromium is 1.3 times higher than the microhardness of the samples obtained from the mixture based on iron.