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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Elsevier
2012
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| Online Access: | http://psasir.upm.edu.my/id/eprint/25293/ http://psasir.upm.edu.my/id/eprint/25293/1/Phase%20equilibria%20and%20electrical%20properties%20of%20pyrochlore%20and%20zirconolite%20phases%20in%20the%20Bi2O3.pdf |
| _version_ | 1848845269957869568 |
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| author | Khaw, Chwin Chieh Tan, Kar Ban Lee, Chnoong Kheng West, Anthony Roy |
| author_facet | Khaw, Chwin Chieh Tan, Kar Ban Lee, Chnoong Kheng West, Anthony Roy |
| author_sort | Khaw, Chwin Chieh |
| building | UPM Institutional Repository |
| collection | Online Access |
| 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. |
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| format | Article |
| id | upm-25293 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English English |
| last_indexed | 2025-11-15T08:44:08Z |
| publishDate | 2012 |
| publisher | Elsevier |
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| spelling | upm-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 |
| 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. |
| title | 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_short | 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. |
| url | http://psasir.upm.edu.my/id/eprint/25293/ http://psasir.upm.edu.my/id/eprint/25293/ http://psasir.upm.edu.my/id/eprint/25293/1/Phase%20equilibria%20and%20electrical%20properties%20of%20pyrochlore%20and%20zirconolite%20phases%20in%20the%20Bi2O3.pdf |