Hydrothermal solvothermal synthesis potassium sodium niobate lead-free piezoelectric ceramics assisted with microwave

Li, Haitao; Yan, Yanfu; Wang, Guangxin; Li, Qian; Gu, Yonghong; Huang, Jinliang

doi:10.1007/s10854-017-7968-1

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Nevertheless, pure KNN ceramics without any dopants prepared by the high-temperature solid-state reaction have yielded an orthorhombic phase, because the phase transition is rapid and reversible. Until today, almost all KNN (including KN and NN) particles prepared by the solution-based synthesis have also shown the most thermodynamically stable orthorhombic phase even after controlling reaction conditions such as alkalinity, molar ratio between constituents, changing organic solvents, and applying microwave. − A few studies separately reported the possible formation of metastable monoclinic KNbO 3 and cubic NaNbO 3 as compositional end members in KNN by solution synthesis ( x = 0 or 1); , the simultaneous control of both phase and stoichiometry has not been achieved particularly in the case of KNN solid solutions owing to the different solubility and reactivity of Na and K niobate salts in solution …”

Section: Introductionmentioning

confidence: 99%

Selective Phase Control of Dopant-Free Potassium Sodium Niobate Perovskites in Solution

et al. 2020

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As one of the perovskite families, potassium sodium niobates (K 1−x Na x )NbO 3 (KNN) have been gaining tremendous attention due to their various functional properties which can be largely determined by their crystallographic phase and composition. However, a selective evolution of different phases for KNN with controlled composition can be difficult to achieve, especially in solution chemical synthesis because of its strong tendency to stabilize into orthorhombic phase at conventional synthetic temperature. We herein developed a facile solution approach to control the phase and composition of dopant-free KNN particles selectively through the modification of reaction parameters. A conventional hydrothermal synthesis method yielded orthorhombic KNN particles, while the monoclinic phase, which has never been observed in a bulk counterpart, was kinetically generated by the compositional modification of an intermediate phase under a high-intensity ultrasound irradiation. Cubic KNN particles were stabilized when ethylene glycol was used as a co-solvent together with deionized water through bonding between ethylene glycol molecules and the surface of the KNN. Composite-structured piezoelectric harvesters were fabricated using each phase of KNN particles and the β-phase poly(vinylidene fluoride-co-trifluoroethylene) polymer. Maximum output power was found for the harvester containing orthorhombic KNN particles. This facile synthetic methodology could pave a new pathway for fabricating numerous phasecontrolled materials.

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Section: Introductionmentioning

confidence: 99%

Selective Phase Control of Dopant-Free Potassium Sodium Niobate Perovskites in Solution

et al. 2020

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“…Therefore, the use of a wet hydrothermal (HT) or solvothermal (ST) synthesis method for obtaining a nano- or micro-structured powder of K 0.5 Na 0.5 NbO 3 seems to be the best choice [ 42 , 43 , 44 , 45 ]. Moreover, the HT/ST method allows better temperature/pressure control, together with a proper precursor mixture, leading to a predictable particle morphology [ 46 ]. Using HT synthesis, starting with Nb foil, at 200 °C for 4 h, sodium niobate nanowires have been successfully synthetized [ 47 ].…”

Section: Introductionmentioning

confidence: 99%

“…For an efficient heating, microwave system can be used assisting the HT method or for sintering step [ 43 ]. Microwave-assisted hydrothermal synthesis method combines the advantages of high-pressure wet technology of hydrothermal (HT) with microwave (MW) heating system on a previously prepared suspension, which leads to higher compositional and submicron-sized particles homogeneity [ 10 , 46 ]. Microwave radiation was volumetrically absorbed leading to the conversion of electromagnetic energy into heat in the volume of irradiated material due to intermolecular friction and, as a result, diffusion processes were enhanced, energy consumption was reduced, heating rates were very rapid and synthesis times were considerably reduced [ 43 ].…”

Section: Introductionmentioning

confidence: 99%

Alkali Niobate Powder Synthesis Using an Emerging Microwave-Assisted Hydrothermal Method

et al. 2022

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For more than five decades, alkali niobate-based materials (KxNa1-xNbO3) have been one of the most promising lead-free piezoelectric materials researched to be used in electronics, photocatalysis, energy storage/conversion and medical applications, due to their important health and environmentally friendly nature. In this paper, our strategy was to synthetize the nearest reproductible composition to KxNa1-xNbO3 (KNN) with x = 0.5, placed at the limit of the morphotropic phase boundary (MPB) with the presence of both polymorphic phases, orthorhombic and tetragonal. The wet synthesis route was chosen to make the mix crystal powders, starting with the suspension preparation of Nb2O5 powder and KOH and NaOH alkaline solutions. Hydrothermal microwave-assisted maturation (HTMW), following the parameter variation T = 200–250 °C, p = 47–60 bar and dwelling time of 30–90 min, was performed. All powders therefore synthesized were entirely KxN1−xNbO3 solid solutions with x = 0.06–0.69, and the compositional, elemental, structural and morphological characterization highlighted polycrystalline particle assemblage with cubic and prismatic morphology, with sizes between 0.28 nm and 2.95 μm and polymorphic O-T phase coexistence, and a d33 piezoelectric constant under 1 pC/N of the compacted unsintered and unpoled discs were found.

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(K, Na)NbO3 lead-free piezoceramics prepared by microwave sintering and solvothermal powder synthesis

Hao

Lin

et al. 2022

Solid State Communications

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Hydrothermal solvothermal synthesis potassium sodium niobate lead-free piezoelectric ceramics assisted with microwave

Cited by 5 publications

References 27 publications

Selective Phase Control of Dopant-Free Potassium Sodium Niobate Perovskites in Solution

Selective Phase Control of Dopant-Free Potassium Sodium Niobate Perovskites in Solution

Alkali Niobate Powder Synthesis Using an Emerging Microwave-Assisted Hydrothermal Method

(K, Na)NbO3 lead-free piezoceramics prepared by microwave sintering and solvothermal powder synthesis

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