Thermal expansion of bismuth magnesium tantalate and niobate pyrochlores

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Thermal expansion of bismuth magnesium tantalate and niobate pyrochlores. / Zhuk, N. A.; Krzhizhanovskaya, M. G.

In: Ceramics International, Vol. 47, No. 21, 01.11.2021, p. 30099-30105.

Research output: Contribution to journal › Article › peer-review

BibTeX

@article{25812fbe5d8445178d68e4b959aea85c,

title = "Thermal expansion of bismuth magnesium tantalate and niobate pyrochlores",

abstract = "The thermal behavior of pyrochlores composing of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) (sp. gr. Fd-3m:2) was studied using the high-temperature X-ray powder diffraction in a wide temperature range of 30–1200 °C. At a temperature above 1080 °C both compounds thermally dissociate forming one of the reaction products MgMO6 (M = Nb, Ta) whose reflexes are traced on X-ray diffraction patterns after cooling the sample down to room temperature. In the case of Bi1·5Mg0·75Nb1·5O6.75 orthoniobate α-BiNbO4 forms at about 800–1020 °C as admixture. The thermal expansion analysis of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) showed that the compounds studied belong to slightly or moderately expanding materials. Thermal expansion for both compounds is isotropic. With a rise in temperature the unit cell parameter a and the thermal expansion coefficient (TEC) are increased uniformly and slightly for M = Ta (Nb): from 10.52822 (10.55325) {\AA} (30 °C) up to 10.59181 (10.62801) {\AA} (1050 °C) and from 3.8 (30 °C) up to 7.4 (8.9) × 10−6 °С−1 at 800 °C respectively. The average TEC values in the range of 30–800 °C range are 5.6 (6.4) × 10−6 °C−1 for M = Ta (Nb) respectively. Bi1.5Mg0.75Nb1.5O6.75 is characterized with the highest thermal expansion that may be related to the longer bond-length of Nb(Bi)–O in the polyhedra.",

keywords = "Bismuth magnesium niobate, Bismuth magnesium tantalate, Ceramics, Thermal expansion pyrochlore, niobate, Bismuth magnesium&nbsp, BEHAVIOR, ELECTRICAL-PROPERTIES, RELAXATION, Bismuth magnesium tantalate&nbsp, pyrochlore, SUBSOLIDUS PHASE-EQUILIBRIA, DIELECTRIC-PROPERTIES, Thermal expansion&nbsp, CERAMICS",

author = "Zhuk, {N. A.} and Krzhizhanovskaya, {M. G.}",

note = "Publisher Copyright: {\textcopyright} 2021 Elsevier Ltd and Techna Group S.r.l.",

year = "2021",

month = nov,

day = "1",

doi = "10.1016/j.ceramint.2021.07.187",

language = "English",

volume = "47",

pages = "30099--30105",

journal = "Ceramics International",

issn = "0272-8842",

publisher = "Elsevier",

number = "21",

}

RIS

TY - JOUR

T1 - Thermal expansion of bismuth magnesium tantalate and niobate pyrochlores

AU - Zhuk, N. A.

AU - Krzhizhanovskaya, M. G.

PY - 2021/11/1

Y1 - 2021/11/1

N2 - The thermal behavior of pyrochlores composing of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) (sp. gr. Fd-3m:2) was studied using the high-temperature X-ray powder diffraction in a wide temperature range of 30–1200 °C. At a temperature above 1080 °C both compounds thermally dissociate forming one of the reaction products MgMO6 (M = Nb, Ta) whose reflexes are traced on X-ray diffraction patterns after cooling the sample down to room temperature. In the case of Bi1·5Mg0·75Nb1·5O6.75 orthoniobate α-BiNbO4 forms at about 800–1020 °C as admixture. The thermal expansion analysis of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) showed that the compounds studied belong to slightly or moderately expanding materials. Thermal expansion for both compounds is isotropic. With a rise in temperature the unit cell parameter a and the thermal expansion coefficient (TEC) are increased uniformly and slightly for M = Ta (Nb): from 10.52822 (10.55325) Å (30 °C) up to 10.59181 (10.62801) Å (1050 °C) and from 3.8 (30 °C) up to 7.4 (8.9) × 10−6 °С−1 at 800 °C respectively. The average TEC values in the range of 30–800 °C range are 5.6 (6.4) × 10−6 °C−1 for M = Ta (Nb) respectively. Bi1.5Mg0.75Nb1.5O6.75 is characterized with the highest thermal expansion that may be related to the longer bond-length of Nb(Bi)–O in the polyhedra.

AB - The thermal behavior of pyrochlores composing of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) (sp. gr. Fd-3m:2) was studied using the high-temperature X-ray powder diffraction in a wide temperature range of 30–1200 °C. At a temperature above 1080 °C both compounds thermally dissociate forming one of the reaction products MgMO6 (M = Nb, Ta) whose reflexes are traced on X-ray diffraction patterns after cooling the sample down to room temperature. In the case of Bi1·5Mg0·75Nb1·5O6.75 orthoniobate α-BiNbO4 forms at about 800–1020 °C as admixture. The thermal expansion analysis of Bi1·5Mg0.75M1.5O6.75 (M = Nb, Ta) showed that the compounds studied belong to slightly or moderately expanding materials. Thermal expansion for both compounds is isotropic. With a rise in temperature the unit cell parameter a and the thermal expansion coefficient (TEC) are increased uniformly and slightly for M = Ta (Nb): from 10.52822 (10.55325) Å (30 °C) up to 10.59181 (10.62801) Å (1050 °C) and from 3.8 (30 °C) up to 7.4 (8.9) × 10−6 °С−1 at 800 °C respectively. The average TEC values in the range of 30–800 °C range are 5.6 (6.4) × 10−6 °C−1 for M = Ta (Nb) respectively. Bi1.5Mg0.75Nb1.5O6.75 is characterized with the highest thermal expansion that may be related to the longer bond-length of Nb(Bi)–O in the polyhedra.

KW - Bismuth magnesium niobate

KW - Bismuth magnesium tantalate

KW - Ceramics

KW - Thermal expansion pyrochlore

KW - niobate

KW - Bismuth magnesium&nbsp

KW - BEHAVIOR

KW - ELECTRICAL-PROPERTIES

KW - RELAXATION

KW - Bismuth magnesium tantalate&nbsp

KW - pyrochlore

KW - SUBSOLIDUS PHASE-EQUILIBRIA

KW - DIELECTRIC-PROPERTIES

KW - Thermal expansion&nbsp

KW - CERAMICS

UR - http://www.scopus.com/inward/record.url?scp=85111067614&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/335d0d45-038a-3977-b38d-f592c2bc60c4/

U2 - 10.1016/j.ceramint.2021.07.187

DO - 10.1016/j.ceramint.2021.07.187

M3 - Article

AN - SCOPUS:85111067614

VL - 47

SP - 30099

EP - 30105

JO - Ceramics International

JF - Ceramics International

SN - 0272-8842

IS - 21

ER -

ID: 84618776