Effects of the doping of W6+ ions on the structure and electrical properties of Pb0.95Ba0.05Nb2O6 piezoelectric ceramics

Piezoelectricity in Excess of 800 pC/N over 400 °C in BiScO3–PbTiO3–CaTiO3 Ceramics

“…As shown in Figure a, the room-temperature d 33 values of BS–PT– x CTO ceramics gradually decrease with the annealing temperature increasing from 20 °C to ∼400 °C, and then quickly decrease to zero at a temperature which is slightly lower than the T C . So the depolarization is the main factor of the d 33 decreasing with increasing annealing temperature. , Although some piezoelectric ceramics with layered perovskite-type structure show a superhigh T C , their d 33 values are much smaller than those of BS–PT– x CTO. ,− Figure b shows the in situ high-temperature d 33 directly measured by the Berlincourt method. The d 33 values of all BS–PT– x CTO ceramics increase with increasing measured temperature until they reach a maximum at a certain temperature above 360 °C.…”

“…Third, BS–PT– x CTO shows a high resistance and a low dielectric loss mainly due to the low density of oxygen vacancies and large band gap at 20–450 °C, so the in situ d 33 , k p , k t , and Q m can be exactly measured. For comparison, Figure d shows the dependence of the room-temperature d 33 value on the ceramic T C of the well-known high-temperature piezoelectric ceramics. − ,− The d 33 value decreases with increasing T C for most piezoelectric ceramics. As an example, the commercial PZT-5A ceramics show a d 33 of 365 pC/N at room temperature and a T C of 365 °C; however, they have a serious depolarization above 200 °C .…”

“…As an example, the commercial PZT-5A ceramics show a d 33 of 365 pC/N at room temperature and a T C of 365 °C; however, they have a serious depolarization above 200 °C . Furthermore, Table summarizes the comprehensive parameters (i.e., T C , d 33 , k p , k t , Q m , ε r , tan δ at 1 kHz, and strain) of the well-known piezoelectric ceramics. − ,− BS–PT–0.005CTO shows the highest d 33 value among the ceramics with a T C larger than 300 °C. Since the BS–PT–0.005CTO ceramic shows the best piezoelectric performances such as d 33 , k p , and k t values in a wide temperature range of 20–440 °C, it can be applied in high-quality sensors to in situ monitor high-temperature devices, such as engine cases and high-speed rotating wheels.…”

“…(c) Gibbs free energy of ceramics near/at the MPBs or T C . (d) Room-temperature piezoelectric d 33 and T C of some piezoelectric ceramics and single crystals, such as CaBi 2 Nb 2 O 9 -based ceramics, − PbNb 2 O 6 -based ceramics, ,− SrBi 2 Nb 2 O 9 -based ceramics, Sr 2 Nb 2 O 7 -based ceramics, Bi 3 TiNbO 9 -based ceramics, , SrBi 4 Ti 4 O 15 -based ceramics, , La 2 Ti 2 O 7 -based ceramics, Bi 4 Ti 3 O 12 -based ceramics, Bi 0.5 Na 0.5 TiO 3 -based ceramics, K 0.5 Na 0.5 NbO 3 -based-ceramics, PNN-based crystals, BiFeO 3 –BaTiO 3 ceramics, − PZT-based ceramics, ,, PMN–PZT single crystals, ,− BaTiO 3 -based ceramics, and BS–PT-based ceramics. ,,, …”

Analysis of Europium Doped Strontium Aluminate Synthesized by Route of PVA Evaporation

“…This composition, depending on the temperature, may exhibit distinct crystallographic forms, as this monoclinic phase at low temperature, while hexagonal phase may be present at higher temperatures [4]. For the synthesis of aluminate in question, there are several simple and versatile methods that are commonly used, as, for example, the most cited in the literature: the sol-gel method and Pechini [5,6]. These methodologies are quite used to permit control of the desired material in a simple, low cost and great responses with regard to homogeneity of the material obtained.…”