Morpho-structural and electrical characterization of Bi-doped apatite-type lanthanum silicates prepared by gel-combustio
- PDF / 2,320,933 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 7 Downloads / 283 Views
Morpho‑structural and electrical characterization of Bi‑doped apatite‑type lanthanum silicates prepared by gel‑combustion I. Perhaita1 · L. E. Muresan1 · A. Nicoara2 · L. Barbu Tudoran3,4 · G. Borodi4 · L. M. Muresan2 Received: 7 May 2020 / Accepted: 17 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract La10−xBix(SiO4)6O3 ceramics (x = 0; 0.1; 0.15; 0.2; 0.3) were obtained from precursors prepared by gel combustion using 3+ l-aspartic acid as fuel. This study presents the effect of Bi doping level and sintering temperature on the morpho-structural and electrical properties of apatites. Processes involved in the apatite formation same as crystallization temperature were examined through TGA. The XRD patterns have showed that all samples adopt the apatite structure and crystallize in the hexagonal space group P-3(147). Samples crystallite size varies between ~ 58 and ~ 118 nm depending on the Bi3+ doping level and the sintering temperature. In order to explain the conduction in apatite, the preferential position of Bi3+ in lattice and the occupancy factors of O5, O6 were calculated by Rietveld refinement. ICP-OES and XPS measurements give the bismuth amount accommodated in apatite lattice and its oxidation states. The morphology, homogeneity and compactness of the ceramics at different Bi doping level were examined through SEM. The relative density of the material is enhanced by the sintering temperature up to 1500 °C, reaching 91.63% for sample doped with 1.5% Bi. Through EIS investigations, the conductivities at 500 °C, for sample doped with 1.5% Bi, are: 9.22 × 10−5 Scm−1 (sintered at 1400 °C) and 1.02 × 10−3 Scm−1 (sintered at 1500 °C), respectively, values which are higher than that of un-doped apatite (6.46 × 10−5 Scm−1). Keywords Bi-doped lanthanum silicates · Apatite-type electrolytes · Combustion · Conductivity
1 Introduction The development of new oxide-ion conducting materials became a very important topic both scientifically and technologically due to their wide applications in oxygen pumps, Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00339-020-03818-6) contains supplementary material, which is available to authorized users. * L. E. Muresan [email protected] 1
Raluca Ripan Institute for Research in Chemistry, BabesBolyai University, 30, Fantanele St., 400294 Cluj‑Napoca, Romania
2
Faculty of Chemistry and Chemical Engineering, Babes- Bolyai University, 11, Arany János St., 400028 Cluj‑Napoca, Romania
3
Electronic Microscopy Centre, Babes- Bolyai University, 5‑7, Clinicilor St., 400006 Cluj‑Napoca, Romania
4
National Institute for Research and Development of Isotopic and Molecular Technologies, 65‑103 Donath St., 400293 Cluj Napoca, Romania
oxygen sensors, oxygen-permeable membrane catalysts or solid oxide fuel cells [1–3]. Up-to-date, the most commonly used ion conductive material is yttria-stabilized zirconia (YSZ) which operates beginning with 800 °C in order to achieve high oxide-ion
Data Loading...
