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Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.

The complete subsolidus phase diagram of the system Bi2O3–ZnO–Ta2O5, including cubic pyrochlore and monoclinic zirconolite phases, has been determined at 950–1050 °C. Through systematic heat treatment and X-ray diffraction of over 100 compositions, the layout of compatibility triangles (both 2-phase...

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Main Authors: Khaw, Chwin Chieh, Tan, Kar Ban, Lee, Chnoong Kheng, West, Anthony Roy
Format: Article
Language:English
English
Published: Elsevier 2012
Online Access:http://psasir.upm.edu.my/id/eprint/25293/1/Phase%20equilibria%20and%20electrical%20properties%20of%20pyrochlore%20and%20zirconolite%20phases%20in%20the%20Bi2O3.pdf
http://psasir.upm.edu.my/id/eprint/25293/
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spelling my.upm.eprints.252932015-09-21T01:11:03Z http://psasir.upm.edu.my/id/eprint/25293/ Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system. Khaw, Chwin Chieh Tan, Kar Ban Lee, Chnoong Kheng West, Anthony Roy The complete subsolidus phase diagram of the system Bi2O3–ZnO–Ta2O5, including cubic pyrochlore and monoclinic zirconolite phases, has been determined at 950–1050 °C. Through systematic heat treatment and X-ray diffraction of over 100 compositions, the layout of compatibility triangles (both 2-phase and 3-phase) and single phase solid solution areas has been determined. Pyrochlore and zirconolite phases have ideal nominal compositions Bi1.5Zn1.0Ta1.5O7 and Bi2(Zn1/3Ta2/3)2O7 respectively, but both form solid solution areas. The sintering condition of pyrochlore pellets has been optimised to obtain high density ceramics with minimal weight loss: optimised condition is 1100 °C for pellets covered with sacrificial powder. Permittivity, ɛ′ dielectric loss and temperature coefficient of capacitance, TCC, of single phase materials were measured using impedance spectroscopy; ɛ′ and TCC show little variation with composition but the losses are higher for Zn-deficient compositions. Elsevier 2012 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/25293/1/Phase%20equilibria%20and%20electrical%20properties%20of%20pyrochlore%20and%20zirconolite%20phases%20in%20the%20Bi2O3.pdf Khaw, Chwin Chieh and Tan, Kar Ban and Lee, Chnoong Kheng and West, Anthony Roy (2012) Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system. Journal of the European Ceramic Society, 32 (3). pp. 671-680. ISSN 0955-2219 10.1016/j.jeurceramsoc.2011.10.012 English
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
English
description The complete subsolidus phase diagram of the system Bi2O3–ZnO–Ta2O5, including cubic pyrochlore and monoclinic zirconolite phases, has been determined at 950–1050 °C. Through systematic heat treatment and X-ray diffraction of over 100 compositions, the layout of compatibility triangles (both 2-phase and 3-phase) and single phase solid solution areas has been determined. Pyrochlore and zirconolite phases have ideal nominal compositions Bi1.5Zn1.0Ta1.5O7 and Bi2(Zn1/3Ta2/3)2O7 respectively, but both form solid solution areas. The sintering condition of pyrochlore pellets has been optimised to obtain high density ceramics with minimal weight loss: optimised condition is 1100 °C for pellets covered with sacrificial powder. Permittivity, ɛ′ dielectric loss and temperature coefficient of capacitance, TCC, of single phase materials were measured using impedance spectroscopy; ɛ′ and TCC show little variation with composition but the losses are higher for Zn-deficient compositions.
format Article
author Khaw, Chwin Chieh
Tan, Kar Ban
Lee, Chnoong Kheng
West, Anthony Roy
spellingShingle Khaw, Chwin Chieh
Tan, Kar Ban
Lee, Chnoong Kheng
West, Anthony Roy
Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
author_facet Khaw, Chwin Chieh
Tan, Kar Ban
Lee, Chnoong Kheng
West, Anthony Roy
author_sort Khaw, Chwin Chieh
title Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
title_short Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
title_full Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
title_fullStr Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
title_full_unstemmed Phase equilibria and electrical properties of pyrochlore and zirconolite phases in the Bi2O3-ZnO-Ta2O5 system.
title_sort phase equilibria and electrical properties of pyrochlore and zirconolite phases in the bi2o3-zno-ta2o5 system.
publisher Elsevier
publishDate 2012
url http://psasir.upm.edu.my/id/eprint/25293/1/Phase%20equilibria%20and%20electrical%20properties%20of%20pyrochlore%20and%20zirconolite%20phases%20in%20the%20Bi2O3.pdf
http://psasir.upm.edu.my/id/eprint/25293/
_version_ 1643828618023927808
score 13.211869

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