Synthesis and study of anhydrous lanthanide orthophosphate (Ln = La, Pr, Nd, Sm) nanowhiskers

Bryukhanova, K. I.; Никифорова, Г. Е.; Гавричев, К. С.

doi:10.17586/2220-8054-2016-7-3-451-458

Cited by 8 publications

(4 citation statements)

References 43 publications

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“…An exception is yttrium orthophosphate, which crystallizes under certain conditions into a phase with a rhabdophane structure that can transform into a phase with a xenotime structure [29]. However, it is also possible to form anhydrous phases with monazite and xenotime structures without the use of high temperatures [30,31].…”

Section: Introductionmentioning

confidence: 99%

Synthesis under hydrothermal conditions and structural transformations of nanocrystals in the LaPO4-YPO4-(H2O) system

Enikeeva,

Proskurina,

Gerasimov

et al. 2023

Nanosystems: Phys. Chem. Math.

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Structural transformations of nanocrystals in the LaPO 4 -YPO 4 -(H 2 O) oxide system were investigated under hydrothermal conditions at 230 • C, depending on isothermal holding times (2 hours, 7 days and 28 days). It was shown that before hydrothermal processing, phases crystallize in the system with rhabdophane structures La 1−x Y x PO 4 • nH 2 O (0 ≤ x ≤ 0.80) and xenotime YPO 4 . It has been determined that increasing the duration of isothermal treatment under hydrothermal conditions leads to the transformation of the rhabdophane phase into phases with monazite and equilibrium xenotime structures, with an intermediate crystallization of the metastable monazite phase. It is noted that only after 28 days of hydrothermal treatment at 230 • C, the system approaches the equilibrium composition of the phases with monazite structures La 0.97 Y 0.03 PO 4 (with crystal sizes of 18-50 nm) and xenotime YPO 4 (with crystal sizes of 45-90 nm). In a single-phase sample with a monazite structure La 0.75 Y 0.25 PO 4 , the average crystal size remains unchanged at around 20 nm after 2 hours, 7 days and 28 days of hydrothermal treatment at 230 • C. KEYWORDS nanocrystals, monazite, xenotime, rhabdophane, structural transformations, yttrium phosphate, lanthanum phosphate. ACKNOWLEDGEMENTS Powder XRD measurements, Rietveld refinement of crystal structures and EDX analysis have been carried out with using the equipment and software of the Engineering Department of the St.

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Section: Introductionmentioning

confidence: 99%

Synthesis under hydrothermal conditions and structural transformations of nanocrystals in the LaPO4-YPO4-(H2O) system

Enikeeva,

Proskurina,

Gerasimov

et al. 2023

Nanosystems: Phys. Chem. Math.

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“…Pre-ceramic powders synthesis is an important stage for obtaining functional materials. The hydrothermal treatment synthesis makes it possible to obtain monazite structured single-phase nanopowders without their subsequent thermal treatment [41][42][43]. Under hydrothermal conditions, the process of structural transformation of the rhabdophane structured La(Y)PO 4 • nH 2 O solid solutions into monazite structured La(Y)PO 4 solid solutions occurs at lower temperatures (T ≈180 • C) than during aerobic calcination (T ≥500 • C) [21,44,45].…”

Section: Introductionmentioning

confidence: 99%

The influence of condition of the monazite structured La0.9Y0.1PO4 nanocrystals sintering on thermal and mechanical properties of the material

Enikeeva¹,

Проскурина²,

Motaylo³

et al. 2021

Nanosystems: Phys. Chem. Math.

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A lanthanum orthophosphate-and yttrium-based monazite structured La 0.9 Y 0.1 PO 4 nanocrystalline material was synthesized. The influence of the thermal treatment temperature on its thermal and mechanical properties has been determined. It was shown that the hydrothermal treatment of coprecipitated phosphates at 230 • C for 110 minutes yielded monazite structured nanoparticles with the crystallite size of about 16 nm. Nanopowder thermal treatment for 20 min in the annealing-quenching mode at 1000-1400 • C resulted in obtaining compact materials, the porosity of which varied from 52 to 27% with the grain growth from ∼20 to ∼100 nm. Active sintering occurred at temperatures above 1300 • C. Nanocrystalline materials obtained by heat treatment at 1200 • C with a grain size of ∼40 nm have a porosity of 42%, microhardness of Hv(25 • C) = 4±0.5 GPa, thermal conductivity λ(25 • C) = 0.4 W•m −1 •K −1 , and can be used as thermal insulation material.

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“…They have applicability as structural [11] and luminescent materials [12,13], thermal barrier coatings [14], as proton-conducting electrolyte [15][16][17][18]. Lanthanum orthophosphate is used as component of two-phase mixtures with refractory oxides to produce reinforced high-temperature ceramics [19].…”

Section: Introductionmentioning

confidence: 99%

Formation of nanocrystals based on equimolar mixture of lanthanum and yttrium orthophosphates under microwave-assisted hydrothermal synthesis

Enikeeva¹,

Проскурина²,

Данилович³

et al. 2020

Nanosystems: Phys. Chem. Math.

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Synthesis and study of anhydrous lanthanide orthophosphate (Ln = La, Pr, Nd, Sm) nanowhiskers

Cited by 8 publications

References 43 publications

Synthesis under hydrothermal conditions and structural transformations of nanocrystals in the LaPO4-YPO4-(H2O) system

Synthesis under hydrothermal conditions and structural transformations of nanocrystals in the LaPO4-YPO4-(H2O) system

The influence of condition of the monazite structured La0.9Y0.1PO4 nanocrystals sintering on thermal and mechanical properties of the material

Formation of nanocrystals based on equimolar mixture of lanthanum and yttrium orthophosphates under microwave-assisted hydrothermal synthesis

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