کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1278608 | 1497560 | 2012 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The effect of cation non-stoichiometry in LaNbO4 materials The effect of cation non-stoichiometry in LaNbO4 materials](/preview/png/1278608.png)
The effect of cation non-stoichiometry in LaNbO4 was investigated by impregnating nano-crystalline LaNbO4 with small amounts of La3+, Nb5+ and Ca2+ oxide precursors. The sintering properties of the modified LaNbO4 powders were investigated by dilatometry, and the microstructure and phase composition were studied by electron microscopy and X-ray diffraction. The electrical properties of the materials were studied by 4-point DC-conductivity and 2-point 4-wire AC-conductivity at elevated temperatures in controlled atmosphere. Minor variations in the cation stoichiometry were shown to have a pronounced effect on both the sintering properties as well as the electrical conductivity. Addition of CaO, which introduced secondary phases above 0.25 mol% CaO, increased the sintering temperature and improved the conductivity of the materials. La2O3- and Nb2O5-excess materials did not show large variation in the electrical conductivity relative to pure LaNbO4, while the sintering properties were strongly affected by the nominal La/Nb ratio in LaNbO4. The present findings demonstrate the sensitivity of cation non-stoichiometry in materials with limited solid solubility.
► The effect of cation non-stoichiometry in LaNbO4 is reported.
► The sintering and microstructure were very sensitive to cation non-stoichiometry.
► The solubility of acceptor dopant in LaNbO4 was confirmed to be very low.
Journal: International Journal of Hydrogen Energy - Volume 37, Issue 9, May 2012, Pages 8017–8026