KMITL
Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1
Browse
Search Results
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Phase Formation, Microstructure and Electric Properties of Vanadium Doped Lead-Free BaTi0.91Sn0.09O3 Ceramics(2023-01-01); Bongkarn, TheerachaiLead-free Ba(Ti<inf>0.91</inf>Sn<inf>0.09</inf>)<inf>1-x</inf>V<inf>x</inf>O<inf>3</inf> (BTSV, x = 0, 0.005,0.010, 0.015, and 0.020) ceramics were prepared by the conventional solid-state sintering method with a calcination temperature of 1200 °C for 2 h and a sintering temperature between 1350 °C and 1400 °C for 4 h. The effect of vanadium (V) doping on the phase formation, microstructure and electrical properties of the ceramics was investigated. X-ray diffraction (XRD) measurements revealed that the ceramics with x = 0 and 0.005 had pure perovskite structures with no detectable impurity, while the ceramics with x ≥ 0.010 exhibited perovskite structures and had secondary impurity phases. Coexisting orthorhombic and tetragonal phases were observed and the Rietveld refinement analysis suggested that the tetragonal phase increased with increased V<sup>5+</sup> substitution. When x increased from 0 to 0.010, the average grain size increased from 47 to 62 µm and then dropped, while the density (ρ) decreased from 5.98 to 5.64 g/cm<sup>3</sup> when x increased. Furthermore, the BTSV ceramics exhibited increased porosity, Curie temperatures (T <inf>C</inf> ∼ 42 °C to 52 °C) and coercive field (E <inf>c</inf>), while the dielectric constant at the Curie temperature (ε<inf>C</inf>) and the remnant polarization (P <inf>r</inf>) of the ceramics decreased (∼18023 to 6110 and ∼7.42 to 4.88 µC/cm<sup>2</sup>, respectively) when V<sup>5+</sup> doping increased. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Classical to Relaxor Ferroelectric Transformation of Lanthanum Modified BaTi0.91Sn0.09O3 Ceramics(2023-01-01); Bongkarn, TheerachaiLead-free Ba<inf>1-x</inf>La<inf>x</inf>Ti<inf>0.91</inf>Sn<inf>0.09</inf>O<inf>3</inf> (BLTS) ceramics with x = 0, 0.01, 0.03 and 0.05, were prepared by the traditional solid-state sintering method with calcination and sintering temperatures of 1200 °C for 2 h and 1400 °C for 4 h, respectively. X-ray diffraction (XRD) measurements revealed that all the BLTS ceramics had pure perovskite structures with no detectable impurities. When x = 0 and 0.01, the ceramics exhibited coexisting orthorhombic (O) and tetragonal (T) phases, while the orthorhombic (O), tetragonal (T) and cubic phase (C) were detected in the BLTS ceramics with x = 0.03 and 0.05, which the Rietveld refinement analysis confirmed. Furthermore, increasing x in the BLTS ceramics led to a large decrease in the average grain size (from 45.7 to 0.9 µm). A significant decrease in the remnant polarization (P <inf>r</inf>) accompanied by very slim hysteresis loops were observed for higher La (x ≥ 0.03) levels. This demonstrates that BLTS ceramics transition from classical ferroelectric to relaxor ferroelectric behavior due to changing occupancy of the A-site to La<sup>3+</sup> from Ba<sup>2+</sup>.1