The influence of different niobium pentoxide precursors on the solid-state synthesis of potassium sodium niobate

Hreščak, Jitka; Benčan, Andreja; Rojac, Tadej; Malič, Barbara

doi:10.1016/j.jeurceramsoc.2013.07.006

Cited by 47 publications

(28 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The result reveals that the calcination temperature to form homogeneous KNN powder from monoclinic Nb 2 O 5 needs to reach 900°C, which is higher than that from orthorhombic Nb 2 O 5 . Similar result was also reported by Hreščak et al…”

Section: Resultssupporting

confidence: 92%

“…These values are significantly lower than the reported values . This result is consistent with previous report, which revealed that monoclinic Nb 2 O 5 had negative effect on piezoelectric properties of KNN ceramics . In contrast, when the powder calcined at the same temperature was used, the samples prepared by TSS exhibit much improved d 33 .…”

Section: Resultssupporting

confidence: 91%

“…However, the effect of Nb 2 O 5 crystal structure on the properties of KNN ceramics has not been given much attention in previous work. To our best knowledge, there is only one report on this topic, which revealed that when monoclinic Nb 2 O 5 was used as the starting material, the resultant KNN powder was not chemically homogeneous, which hurt its sintering capability and led to lower piezoelectric properties . However, this study did not suggest any method to eliminate this negative effect of monoclinic Nb 2 O 5 .…”

Section: Introductionmentioning

confidence: 64%

See 2 more Smart Citations

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering

Jiao

Chen

2017

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

This study investigates the electrical properties of (K0.5Na0.5)NbO3 (KNN) lead‐free piezoelectric ceramics prepared by using monoclinic Nb2O5 as the starting material. The results reveal that the samples prepared by two‐step sintering procedure are much better than those prepared by conventional sintering procedure. The piezoelectric constant (d33) reaches the value measured from the samples prepared from orthorhombic Nb2O5, suggesting the two‐step sintering procedure could be an effective method to remove the negative effect of monoclinic Nb2O5. The underlying mechanism for the improving effect is discussed.

show abstract

Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 64%

See 1 more Smart Citation

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering

Jiao

Chen

2017

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

show abstract

“…For higher x values, T m increases with x increasing. Moreover, an elevated dielectric constant is observed for the majority of the compounds, which is highest (ε′ max = 9500) for x = 0.90 [14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41]. Considering all these aspects, i.e.…”

Section: Introductionmentioning

confidence: 99%

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

et al. 2016

View full text Add to dashboard Cite

Lead free piezoelectric materials are being intensively investigated in order to substitute lead based ones, commonly used in many different applications. Among the most promising lead-free materials are those with modified NaNbO3, such as (K, Na)NbO3 (KNN) and (Ba, Na)(Ti, Nb)O3 (BTNN) families. From a ceramic processing point of view, high density single phase KNN and BTNN ceramics are very difficult to sinter due to the volatility of the alkaline elements, the narrow sintering temperature range and the anomalous grain growth. In this work, Spark Plasma Sintering (SPS) and high-energy ball milling (HEBM), following heat treatments (calcining and sintering), in oxidative (O2) atmosphere have been used to prepare single phase highly densified KNN (“pure” and Cu2+ or Li1+ doped), with theoretical densities ρth > 97% and BTNN ceramics (ρth ~ 90%), respectively. Using BTTN ceramics with a P4mm perovskite-like structure, we showed that by increasing the NaNbO3 content, the ferroelectric properties change from having a relaxor effect to an almost “normal” ferroelectric character, while the tetragonality and grain size increase and the shear piezoelectric coefficients (k15, g15 and d15) improve. For KNN ceramics, the results reveal that the values for remanent polarization as well as for most of the coercive field are quite similar among all compositions. These facts evidenced that Cu2+ may be incorporated into the A and/or B sites of the perovskite structure, having both hardening and softening effects.

show abstract

“…Recently, we published a study that stresses again the importance of the solid-state synthesis precursors in KNN. Hreščak et al [18] discovered that it is not only the particle size distribution of the Nb 2 O 5 that is important, so is its polymorphic form. The as-received orthorhombic and monoclinic Nb 2 O 5 were each used to prepare a batch of KNN in a solid-state synthesis with potassium and sodium carbonates.…”

Section: Introductionmentioning

confidence: 99%

Solid-state synthesis of undoped and Sr-doped K0.5Na0.5NbO3

Hreščak

Malič

Cilenšek

et al. 2016

J Therm Anal Calorim

Self Cite

View full text Add to dashboard Cite

The solid-state synthesis of undoped K 0.5 Na 0.5-NbO 3 (KNN) and KNN doped with 1, 2 and 6 mol% Sr, from potassium, sodium and strontium carbonates with niobium pentoxide, was studied using thermal analysis and in situ high-temperature X-ray diffraction (HT-XRD). The thermogravimetry and the differential thermal analyses with evolved-gas analyses showed that the carbonates, which were previously reacted with the moisture in the air to form hydrogen carbonates, partly decomposed when heated to 200°C. In the temperature interval where the reaction was observed, i.e., between 200 and 750°C, all the samples exhibited the main mass loss in two steps. The first step starts at around 400°C and finishes at 540°C, and the second step has an onset at 540°C and finishes with the end of the reaction between 630 and 675°C, depending on the particle size distribution of the Nb 2 O 5 precursor. According to the HT-XRD analysis, the perovskite phase is formed at 450°C for all the samples, regardless of the Sr content. The formation of a polyniobate phase with a tetragonal tungsten bronze structure was detected by HT-XRD in the KNN with the largest amount of Sr dopant, i.e., 6 mol% of Sr, at 600°C.

show abstract

The influence of different niobium pentoxide precursors on the solid-state synthesis of potassium sodium niobate

Cited by 47 publications

References 17 publications

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

Solid-state synthesis of undoped and Sr-doped K0.5Na0.5NbO3

Contact Info

Product

Resources

About

The influence of different niobium pentoxide precursors on the solid-state synthesis of potassium sodium niobate

Cited by 47 publications

References 17 publications

Eliminating the negative effect of monoclinic Nb2O5 on electrical properties of (K0.5Na0.5)NbO3 ceramics by two‐step sintering

Eliminating the negative effect of monoclinic Nb2O5 on electrical properties of (K0.5Na0.5)NbO3 ceramics by two‐step sintering

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

Solid-state synthesis of undoped and Sr-doped K0.5Na0.5NbO3

Contact Info

Product

Resources

About

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering

Eliminating the negative effect of monoclinic Nb₂O₅ on electrical properties of (K_0.5Na_0.5)NbO₃ ceramics by two‐step sintering