powderИзвестия вузов. Порошковая металлургия и функциональные покрытияPowder Metallurgy аnd Functional Coatings (Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional'nye Pokrytiya)1997-308X2412-8767НИТУ "МИСИС"10.17073/1997-308X-2026-1-34-44powder-1099Research ArticleТугоплавкие, керамические и композиционные материалыRefractory, Ceramic, and Composite MaterialsВлияние стехиометрии на усадку и рост зерен в бинарных и высокоэнтропийных карбидах при искровом плазменном спеканииEffect of stoichiometry on sintering shrinkage and grain growth in binary and high-entropy carbides during spark plasma sinteringhttps://orcid.org/0000-0001-6309-8218ВолодькоС. С.VolodkoS. S.

Сергей Сергеевич Володько – к.т.н., вед. эксперт научного проекта

Россия, 119049, г. Москва, Ленинский пр-т, 4, стр. 1

Sergey S. Volodko – Cand. Sci. (Eng.), Leading Research Expert of the Project

1 Bld, 4 Leninskiy Prosp, Moscow 119049, Russia

volodko.sv@yandex.ruhttps://orcid.org/0000-0001-5168-4885МосковскихД. О.MoskovskikhD. O.

Дмитрий Олегович Московских – к.т.н., директор научно-исследовательского центра «Конструкционные керамические наноматериалы»

Россия, 119049, г. Москва, Ленинский пр-т, 4, стр. 1

Dmitry O. Moskovskikh – Cand. Sci. (Eng.), Head of the Research Center “Structural Ceramic Nanomaterials”

1 Bld, 4 Leninskiy Prosp, Moscow 119049, Russia

mos@misis.ruhttps://orcid.org/0000-0002-0531-002XЮдинС. Н.YudinS. N.

Сергей Николаевич Юдин – к.т.н., вед. эксперт научного проекта

Россия, 119049, г. Москва, Ленинский пр-т, 4, стр. 1

Sergey N. Yudin – Cand. Sci. (Eng.), Leading Research Expert of the Project

1 Bld, 4 Leninskiy Prosp, Moscow 119049, Russia

sergey-usn@mail.ruhttps://orcid.org/0000-0002-9387-0237КусковК. В.KuskovK. V.

Кирилл Васильевич Кусков – вед. эксперт научного проекта

Россия, 119049, г. Москва, Ленинский пр-т, 4, стр. 1

Kuskov K. Vasilievich – Leading Research Expert of the Project

1 Bld, 4 Leninskiy Prosp, Moscow 119049, Russia

kkuskov@misis.ruНациональный исследовательский технологический университет «МИСИС»РоссияNational University of Science and Technology “MISIS”Russian Federation2026030420262013444Copyright © НИТУ "МИСИС", 20262026НИТУ "МИСИС"НИТУ "МИСИС"https://powder.misis.ru/jour/about/submissions#copyrightNoticehttps://powder.misis.ru/jour/article/view/1099

Ультрамелкозернистые (УМЗ) керамические материалы проявляют повышенную надежность в сравнении с крупно­кристаллической керамикой за счет наличия большего количества межзеренных границ. Это позволяет увеличивать путь трещины при межкристаллитном разрушении, что особенно полезно для композитных материалов, где такое разрушение, как правило, доминирует. Получение УМЗ-структуры требует понимания особенностей спекания и роста зерен в керамических материалах. В настоящей работе субмикронные стехиометрические (C/Me = 1) и нестехиометрические (C/Me = 0,8) однофазные порошки (d = 150÷350 нм) бинарных и высокоэнтропийных карбидов (ВЭК) получали методом кальций-карботермического синтеза. Керамические порошки подвергали искровому плазменному спеканию (ИПС), варьи­руя температуру в диапазоне 1350–1950 °С и время процесса в интервале 0–20 мин. Исследовалось влияние температуры ИПС и стехиомет­рии порошков на рост зерна, усадку при спекании, а также на энергию активации спекания и собирательной рекристаллизации. Проведено сравнение ВЭК и карбида тантала. Показано, что стехиометрия карбидов оказывает влияние на процессы спекания. Снижение стехиометрии, т.е. повышение концентрации углеродных вакансий, уменьшает величину энергии активации спекания и собирательной рекристаллизации, а также увеличивает скорость усадки. Показано, что момент начала роста зерна не зависит от стехиометрии и начинается при плотности ~0,9÷0,95, при этом в плотной керамике (>0,95) рост зерна происходит наиболее интенсивно в стехиометрических карбидах, что наблюдается в ВЭК и TaC.

Ultrafine-grained (UFG) ceramic materials exhibit improved reliability compared with coarse-grained ceramics due to the higher density of grain boundaries. This increases the crack propagation path during intergranular fracture, which is particularly beneficial for composite materials where intergranular fracture typically dominates. The formation of a UFG structure requires a detailed understanding of the sintering behavior and grain growth mechanisms in ceramic materials. In this study, submicron single-phase powders (150–350 nm) of binary and high-entropy carbides (HECs) of stoichiometric (C/Me = 1) and non-stoichiometric (C/Me = 0.8) compositions were obtained by the calcium-carbothermic synthesis. The powders were  consolidated by spark plasma sintering (SPS) at temperatures of 1350–1950 °C with holding times of 0–20 min. The effect of SPS temperature and powder stoichiometry on grain growth, sintering shrinkage, and the activation energy of sintering and grain coarsening was investigated. The behavior of high-entropy carbides was compared with that of tantalum carbide. The results show that carbide stoichiometry  significantly affects sintering behavior. A decrease in stoichiometry, corresponding to an increased concentration of carbon vacancies, reduces the activation energy of sintering and grain coarsening and increases the shrinkage rate. The onset of grain growth was found to be independent of stoichiometry and occurs at a relative  density of ~0.90÷0.95. In highly dense ceramics (>0.95), grain growth proceeds most intensively in stoichiometric carbides, which is observed both in HECs and in TaC.

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The authors declare that there are no conflicts of interest present.