Impedance studies of K0.5Na0.5NbO3 ceramics prepared from mechanochemically activated powders

Adamczyk-Habrajska, Małgorzata; Szafraniak-Wiza, Izabela; Goryczka, Tomasz; Szalbot, Diana

doi:10.1016/j.matchemphys.2019.122451

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…Even after such a relatively long milling time of 100 h, the amorphization was not complete. As has been widely described in our previous paper [18], the analysis of the results of X-ray investigations clearly confirmed the presence of a single phase in the sample. All the lines visible on the X-ray diffraction patterns point to an orthorhombic type of structure.…”

Section: Resultssupporting

confidence: 84%

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

et al. 2020

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Alkaline based materials have been considered as a replacement for environmentally harmful Pb(Zr,Ti)O3 (PZT) electro-ceramics. In this paper, the K1/2Na1/2NbO3 (KNN) ceramics were prepared in a three stage process: first Nb2O5, Na2CO3, and K2CO3 were milled in a high energy mill (shaker type) for different periods, between 25 h and 100 h, consecutively a solid state reaction was carried out at 550 °C. Finally, the uniaxially pressed samples were sintered at 1000 °C. The reaction temperature is lower for mechanically activated powders than in the case of the conventional solid-state method. The ceramic samples, prepared from the mechanically activated powders, were investigated by dielectric spectroscopy. The influence of the duration of the mechanical activation on the properties of the ceramic materials, e.g., ceramic microstructures, phase transition temperatures, character of the temperature dependences of dielectric permittivity, are discussed.

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Section: Resultssupporting

confidence: 84%

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

et al. 2020

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“…The impedance of KNN ceramics has also been studied. 174 With the increase in high-energy grinding time, grain resistance and grain boundary resistance increased, and a similar trend was observed in terms of capacitance. KNN powders are composed of irregular particles with rounded edges and grain sizes ranging from 100 nm to several microns.…”

Section: K 5 Na 5 Nbo 3 Ceramic Powdersupporting

confidence: 59%

“…Compared to conventional solid‐state methods, high‐performance KNN ceramics have shorter production times. The impedance of KNN ceramics has also been studied 174 . With the increase in high‐energy grinding time, grain resistance and grain boundary resistance increased, and a similar trend was observed in terms of capacitance.…”

Section: Mechanochemical Synthesis Of Oxide Ceramic Powdersmentioning

confidence: 74%

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Mechanochemical synthesis of nanostructured and composite oxide ceramics: From mechanisms to tailored properties

Zhang,

Xu,

Zhang

et al. 2023

Int J Applied Ceramic Tech

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Mechanochemical synthesis is a technology formed in the 1950s. By applying mechanical energy, mechanochemical synthesis stimulates chemical reactions, causing structural and phase changes and enabling difficult or otherwise impossible reactions to occur. Mechanochemical reactions are relatively safe, clean and efficient. At present, the synthesis of oxide ceramic materials by mechanochemical methods has attracted widespread attention. In the production of oxide ceramic materials, the characteristics of ceramic powder have a certain influence on the molding, sintering, microstructure, and mechanical properties of subsequent ceramics. In this paper, the research progress of mechanical chemistry in the synthesis of nanostructures and composite oxide ceramic powders is reviewed. The effects of process parameters such as ball milling time, speed, atmosphere, grinding media, additives, and ball‐to‐powder ratio on reaction kinetics, phase formation, and powder properties are summarized. In addition, challenges and opportunities for ceramic powder synthesis are also discussed.

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“…In contrast, electronic compensation is the reason for the increase in conductivity, in which the number of charge carriers equals the charge of the lanthanum ion [16]. Lanthanum barium titanate is an alternative material to other lead-free perovskites such as K 0.5 Na 0.5 NbO 3 [19], (K 0.38 Na 0.52 Li 0.04 )-(Nb 0.86 Ta 0.1 Sb 0.04 )O 2.97 [20,21], and KNbO 3 [21]. The BLT4 ceramics presented in the manuscript are characterized by a high value of dielectric permittivity at room temperature as well as at Curie temperature.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

et al. 2020

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This paper describes the properties of a lead-free ceramic material based on barium titanate, designed for the construction of ultracapacitors and sensors used in mechatronic systems. The admixture of lanthanum (La3+) served as a modifier. The ceramic powders were obtained by the solid phase reaction method (conventional method—mixed oxides method—MOM). Technological conditions of the synthesis process were determined on the basis of thermal analysis. The obtained samples are characterized, at room temperature (Tr < TC), by a single-phase tetragonal structure and a P4mm space group. Properly developed large grains (d = 5 µm) contributed to the increase in electric permittivity, the maximum value of which is at the level of εm ≈ 112,000, as well as to a strong decrease in specific resistance in the ferroelectric phase, whereas above the Curie temperature, by creating a potential barrier at their boundaries, there was a a rapid increase in resistivity. The temperature coefficient of resistance of the obtained posistor is 10.53%/K. The electrical properties of the obtained ceramics were examined using impedance spectroscopy. In order to analyze the obtained results, a method of comparing the behavior of the real object and its replacement system in a specific frequency region was used, whereas the Kramer–-Kroning (K–K) test was used to determine the consistency of the measured data. The proper selection of the stoichiometry and synthesis conditions resulted in the creation of an appropriate concentration of donor levels and oxygen gaps, which in turn resulted in a significant increase in the value of electrical permittivity, with small values of the angle of dielectric loss tangent. This fact predisposes the discussed material for certain applications (in the construction of ultracapacitors, among others).

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Impedance studies of K0.5Na0.5NbO3 ceramics prepared from mechanochemically activated powders

Cited by 6 publications

References 30 publications

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

Preparation and Dielectric Properties of K1/2Na1/2NbO3 Ceramics Obtained from Mechanically Activated Powders

Mechanochemical synthesis of nanostructured and composite oxide ceramics: From mechanisms to tailored properties

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

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