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CHEMISTRY AND MATERIAL SCIENCE
Phase formation and thermal analysis in the LaPO$_4$–GdPO$_4$–H$_2$O system
Maria O. Enikeevaab, Kseniya A. Zhidomorovabc, Dmitriy P. Danilovichc, Vladimir N. Nevedomskiya, Olga V. Proskurinaac, Victor V. Gusarova a Ioffe Institute, St. Petersburg, Russia
b Branch of Petersburg Nuclear Physics Institute named after B.P. Konstantinov of National Research Centre
"Kurchatov Institute" – Institute of Silicate Chemistry, St. Petersburg, Russia
c St. Petersburg State Institute of Technology, St. Petersburg, Russia
Аннотация:
Structural transformations of nanocrystals in the LaPO$_4$–GdPO$_4$–(H$_2$O) system under hydrothermal conditions at 230$^\circ$C were studied depending on the duration of isothermal holding (2 hours, 3 days, and 5 days). It has been shown that a phase with the rhabdophane-like structure, La$_{1-x}$Gd$_x$PO$_4$ $\cdot$ $n$ H$_2$O (0.00 $\le x\le$ 1.00), exhibits a weighted average crystallite size of 4–7 nm and crystallizes in the system prior to hydrothermal treatment. As a result of hydrothermal treatment, samples in the LaPO$_4$–GdPO$_4$–(H$_2$O) system are completely transformed into a phase with a monazite structure within five days, with the slowest transformation observed for gadolinium orthophosphate. It was found that nanoparticles with a rhabdophane structure, GdPO$_4$ $\cdot$ $n$H$_2$O, possess a single-crystal structure. The thermal analysis data indicated that the samples obtained via the precipitation method contain an X-ray amorphous phase and impurity compounds. The onset temperature of the structural transformation from rhabdophane to monazite, as well as the number of water molecules in the rhabdophane-like structure, depends on the chemical composition of the compound, particularly with regard to the isomorphic substitution of lanthanum cations with gadolinium cations.
Ключевые слова:
solid solution, rhabdophane structure, thermal analysis, structural transformations.
Поступила в редакцию: 30.09.2024 Исправленный вариант: 11.11.2024 Принята в печать: 25.11.2024
Образец цитирования:
Maria O. Enikeeva, Kseniya A. Zhidomorova, Dmitriy P. Danilovich, Vladimir N. Nevedomskiy, Olga V. Proskurina, Victor V. Gusarov, “Phase formation and thermal analysis in the LaPO$_4$–GdPO$_4$–H$_2$O system”, Наносистемы: физика, химия, математика, 15:6 (2024), 781–792
Образцы ссылок на эту страницу:
https://www.mathnet.ru/rus/nano1324 https://www.mathnet.ru/rus/nano/v15/i6/p781
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