| Budget Amount *help |
¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000)
Fiscal Year 2015: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2014: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2013: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2012: ¥9,360,000 (Direct Cost: ¥7,200,000、Indirect Cost: ¥2,160,000)
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| Outline of Final Research Achievements |
The b-axis-oriented polycrystalline Na0.85Ti0.51Ga4.37O8 (NTGO) was prepared using the reactive diffusion technique. When the sandwich-type Ga2TiO5/NaGaO2/Ga2TiO5 diffusion couple was heated at 1323 K for 24 h, the NTGO polycrystal was readily formed in the presence of a liquid phase. We mechanically extracted the thin-plate electrolyte consisting of the grain-aligned NTGO polycrystal. The ionic conductivity of the electrolyte along the common b-axis direction steadily increased from 1.3×10-4 to 7.3×10-3 S/cm as the temperature increased from 573 to 1073 K. The NTGO showed the crystal structure (space group C2/m) with substantial positional disordering of one of the two Ga sites. The Na ions occupied ca. 43% of the Wyckoff position 4i site, the deficiency of which would contribute to the relatively high ionic conductivity along the b-axis. The reactive diffusion would be widely applicable as the novel technique to the preparation of grain-aligned ceramics of multi-component systems.
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