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Sains Malaysiana 39(3)(2010): 479–484
Effect
of Zirconium Substitution on the Phase Formation and Microstructure of BaCeO3
(Kesan Penggantian Zirkonium ke Atas Pembentukan Fasa danMikrostruktur BaCeO3)
N. Osman1*, I.A. Talib2 & H.A. Hamid1
1Faculty
of Applied Sciences, Universiti Teknologi MARA 02600 Arau, Perlis, Malaysia
2Faculty
of Science & Technology, Universiti Kebangsaan
Malaysia 43600 Bangi, Selangor Malaysia
Received: 22 June 2009 / Accepted: 10
September 2009
ABSTRACT
Polycrystalline compounds of Ba(Ce1-xZrx)0.95Yb0.05O2.975 (0.20 ≤ x ≤ 0.40) were
prepared by the conventional solid state reaction method. All the samples
exhibited the orthorhombic structure of BaCeO3.
The particle size and morphology of the powdered samples were found to change
gradually with Zr content. The sample with x=0.40
showed more agglomerates of about 10.0 μm in
size, and the particles constituting the agglomerates were smaller than 1.0 μm. For the polished and etched pelleted samples, only the x=0.20 sample showed clear grain shapes with sizes in the
range of 1.0 to 3.0 μm. By increasing the Zr content to more than 20 mol%, the grain sizes became
less pronounced and smaller. The deficiency of Ba that caused the formation of a Ce, Zr and Yb-rich sample was
detected by energy dispersive X-ray measurement. Ba deficiency was attributed to the loss of BaO during
the calcination and sintering processes.
Keywords: Cerate-zirconate;
microstructure; oxides ceramic; phase formation
ABSTRAK
Polihablur sebatian polihablur Ba(Ce1-xZrx)0.95Yb0.05O2.975 (0.20 ≤ x ≤ 0.40) telah disediakan melalui kaedah tindak balas keadaan pepejal konveksional. Semua sampel menunjukkan struktur ortorombik bagi BaCeO3. Saiz zarah dan morfologi serbuk sampel didapati berubah dengan kandungan Zr. Sampel dengan x=0.40 mempamerkan banyak aglomerat yang bersaiz lebih kurang 10.0 μm dan zarah-zarah yang membentuk aglomerat tersebut bersaiz lebih kecil daripada 1.0 μm. Untuk pelet yang digilap dan dipunarkan, hanya sampel x=0.20 menunjukkan bentuk butiran yang jelas dengan saiz antara 1.0 hingga 3.0 μm. Dengan penambahan kandungan Zr lebih daripada 20 %mol, saiz butiran menjadi kurang jelas dan semakin mengecil. Kekurangan unsur Ba yang dikesan menggunakan spektroskopi sebaran tenaga sinar-X telah menyebabkan pembentukan fasa yang kaya dengan Ce, Zr and Yb di dalam sampel kajian. Kekurangan unsur Ba ini adalah disebabkan oleh kehilangan BaO semasa proses pengkalsinan dan persinteran.
Kata kunci: Mikrostruktur; pembentukan fasa; serat-zirkonat; seramik oksida
REFERENCES
Azad, A.K. & Irvine, J.T.S.
2007. Synthesis, chemical stability and proton conductivity of the perovskites Ba(Ce, Zr)1- xScxO3-δ. Solid State Ionics 178: 635-640.
Bae, J.S., Choo, W.K.
& Lee, C.H. 2001. The crystal structure of Ba(Ce0.8Zr0.2)O3. Journal of the European Ceramic Society 21: 1779-1782.
Haile, S.M., Staneff, G. & Ryu, K.H. 2001. Non-stoichiometry, grain boundary transport and chemical
stability of proton conducting perovskites. Journal
of Materials Science 36: 1149-1160.
Iwahara, H. 1992.
Oxide-ionic and protonic conductors based on perovskite-type oxides and their possible applications. Solid
State Ionics 52: 99-104.
Katahira, K., Kohchi, Y., Shimura, T. & Iwahara,
H. 2000. Protonic conduction in Zr-substituted
BaCeO3. Solid State Ionics 138:
91-98.
Matzke, T. & Cappadonia, M. 1996. Proton conductive perovskite solid solutions with enhanced mechanical stability. Solid State Ionics 86-88:
659-663.
Osman, N., Jani, A.M. & Talib, I.A. 2006. Synthesis of Yb-doped Ba(Ce, Zr)O3 ceramic
powders by sol-gel method. Ionics 12: 379-384.
Ryu, K.H. & Haile, S.M. 1999. Chemical stability and proton conductivity of
doped BaCeO3-BaZrO3 solid
solutions. Solid State Ionics 125: 355-367.
Snijkers, F.M.M., Buekenhoudt, A., Cooymans, J. & Luyten, J.J. 2004a Proton conductivity and phase composition in BaZr0.9Y0.1O3-α. Scripta Materialia 50: 655-659.
Snijkers, F.M.M., Buekenhoudt, A., Luyten, J.J., Cooymans J. & Mertens, M. 2004b. Proton conductivity in perovskite type yttrium doped barium hafnate. Scripta Materialia 51: 1129- 1134.
Yajima, T., Suzuki,
H., Yogo, T. & Iwahara,
H. 1992. Protonic conduction in SrZrO3 based
oxides. Solid State Ionics 51: 101-107.
*Corresponding author; email: fisha@perlis.uitm.edu.my
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