Synthesis and Characterization of Oxide Conductors in Pbo-Bi2o3-M2o5 (M = V, P, As)
Materials of compositions PbBi6M2O15 and (PbO)n(BiMO4), where M = V, P, As and n = 1, 2, 4 were prepared via solid state reaction. These materials were characterised using X-ray diffraction (XRD), density measurement, inductively coupled plasmaatomic emission spectrometry (ICP-AES), ac impedance...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2004
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| Online Access: | http://psasir.upm.edu.my/id/eprint/62/1/1000548970_t_FSAS_2004_13.pdf http://psasir.upm.edu.my/id/eprint/62/ |
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| Summary: | Materials of compositions PbBi6M2O15 and (PbO)n(BiMO4), where M = V, P, As and
n = 1, 2, 4 were prepared via solid state reaction. These materials were characterised
using X-ray diffraction (XRD), density measurement, inductively coupled plasmaatomic
emission spectrometry (ICP-AES), ac impedance spectroscopy, differential
thermal analysis (DTA), thermogravimetry analysis (TGA), Fourier-transform
infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).
Complete solid solution series were obtained in the PbBi6V2O15-PbBi6P2O15,
PbBi6V2O15-PbBi6As2O15 and PbBi6P2O15-PbBi6As2O15 systems. All the materials
were isostructural, and crystallised in orthorhombic symmetry. However, the cell
parameter a of these materials was twice those reported in JCPDS. The conductivity
of these materials decreased in the order of PbBi6V2O15 > PbBi6As2O15 >
PbBi6P2O15. PbBi6V2O15 is an oxide ion conductor as it has a transference number of
0.8 above 650ºC.
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Substitution of Sr for Pb in PbBi6V2O15 resulted in the formation a new material of
SrBi6V2O15 with higher conductivity. On the other hand, Pb in both PbBi6V2O15 and
PbBi6As2O15 could be replaced by Na and Bi, resulting in the formation of
NaBi13V4O30 and NaBi13As4O30. Besides successfully suppressing the phase
transition observed in PbBi6V2O15, these materials had higher conductivity compared
to that of PbBi6(V/As)2O15. The conductivity of these materials was in the range of ~
10-3 ohm-1 cm-1 at 800°C. Conductivity decreased in the order of NaBi13V4O30 >
SrBi6V2O15 > PbBi6V2O15. These materials appeared to be oxide ion conductors.
Complete solid solution series were formed in the Pb2BiPO6-Pb2BiAsO6, Pb4BiPO8-
Pb4BiVO8, Pb4BiPO8-Pb4BiAsO8 and Pb4BiVO8-Pb4BiAsO8 systems. The properties
determined generally agreed with those reported; these materials were mixed oxide
ion conductors. The conductivity decreased in the order of Pb2BiMO6 > PbBiMO5 >
Pb4BiMO8, and V > As > P. |
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