Effect of excess Nb2O5 on the growth behavior of KSr2Nb5O15 particles by molten salt synthesis

J Mater Sci: Mater Electron

2015

Self Cite

Further enhancement of the piezoelectric response in lead-free piezoelectric ceramics can be accomplished by inducing preferred orientation. In this paper, attempts have been made to review the progress on the fabrication of lead-free textured piezoelectric ceramics by the (reaction) templated grain growth method. The preparation (molten salt synthesis) and alignment (tape casting and extrusion molding) of anisometric template particles were introduced in detail. The texture evolution with heating was visualized by computer simulation. The review of lead-free textured piezoelectric ceramics focused on four promising systems: Na 0.5 Bi 0.5 TiO 3 -based, K 0.5 Na 0.5 NbO 3 -based, Ba(Zr 0.2 Ti 0.8 )O 3 -(Ba 0.7 Ca 0.3 )TiO 3 and KSr 2 Nb 5 O 15 . It is suggested that texturing of lead-free morphotropic phase boundary compositions will be required in order to realize viable lead-free alternatives to current lead-based materials.

Section: Particle Formationmentioning

confidence: 99%

“…A typical example is the preparation of needlelike KSr 2 Nb 5 O 15 particles as shown in Fig. 4 [45,46]. The anisometric KSr 2 Nb 5 O 15 particles can be synthesized by reacting KCl salt with oxides powder (SrCO 3 and Nb 2 O 5 ), e.g.…”

Section: Particle Formationmentioning

confidence: 99%

Progress on the fabrication of lead-free textured piezoelectric ceramics: perspectives over 25 years

J Mater Sci: Mater Electron

2015

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“…So, it was impolitic to prepare pure Na 0.5 Sr 0.25 NbO 3 particles by increasing NaCl content because oozed molten salt never acted as a solvent. [8]. It came to a conclusion that Na 0.5 Sr 0.25 NbO 3 could be prepared via simple ion-exchange reaction from KSN.…”

Section: S?n?n Systemmentioning

confidence: 99%

“…Alkali and alkalineearth niobates compounds are also known as lead-free functional materials due to a framework structure of NbO 6 octahedral [4][5][6][7][8]. Among lead-free functional ceramics families, strontium sodium niobates are of particular interest recently since they exhibit excellent dielectric, electrooptic, piezoelectric, ferroelectric and pyroelectric properties [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Preparation of cubic Na0.5Sr0.25NbO3 particles by molten salt synthesis

J Mater Sci: Mater Electron

Gao

Zhang

2014

Self Cite

Pure Na 0.5 Sr 0.25 NbO 3 particles were successfully synthesized using the molten salt synthesis method in the SrCO 3 ?Nb 2 O 5 ?KCl?NaCl system, which could not be obtained in the SrCO 3 ?Nb 2 O 5 ?NaCl system. The result suggested that the fabrication process of Na 0.5 Sr 0.25 NbO 3 was different for the two systems. In the SrCO 3 ?Nb 2 O 5 ?NaCl system, NaSr 2 Nb 5 O 15 formed and then converted into Na 0.5 Sr 0.25 NbO 3 . In the SrCO 3 ?Nb 2 O 5 ?KCl?NaCl system, Na 0.5 Sr 0.25 NbO 3 could be obtained directly by the reaction between the intermediate KSN and NaCl. The effects of the NaCl salt content and heated temperature on the purity and size of particles were investigated. Pure Na 0.5 Sr 0.25 NbO 3 powder crystals with uniform particle size could be prepared at the heated temperature of 1,200°C and NaCl salt-to-oxide ratio of 2, which were ideal raw material for preparing Na 0.5 Sr 0.25 NbO 3 ceramics.

“…In addition, Mss provides efficient control over the purity and morphology of the resulting powders. In our previous study, pure Ksn particles with better morphology were also synthesized by the Mss method [17], [18].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and dielectric behavior of Bi2O3-doped KSr2Nb5O15 ceramics

Gao

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

et al. 2013

Bi 2 O 3 -doped KSr 2 Nb 5 O 15 (KSNB) ceramics with relative density higher than 96% were successfully prepared by sintering at 1300°C. The addition of Bi 2 O 3 will decrease the tetragonal degree of the materials, improve the densification, and promote the grain growth of KSNB ceramics. Relaxation behavior can be observed in KSNB ceramics, which is attributed to the complex response of the polar nanoregions and matrices resulting from substitution of Bi 3+ for Sr 2+ and K + . Bi 2 O 3 -doped KSr 2 Nb 5 O 15 ceramics show good temperaturedependence performance and high dielectric tunability. KSNB ceramics with 4.0 wt% added Bi 2 O 3 show the maximum tunability, and capacitance changes with temperature meet the requirement of the X7R standard, which makes these ceramics promising candidate materials for multilayer capacitors and tunable phase shifters.