Special Issue "Sintering and Grain Growth Behavior of Ceramics"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Structure Analysis and Characterization".

Deadline for manuscript submissions: 30 June 2020.

Special Issue Editor

Prof. Dr. John G. Fisher
E-Mail Website
Guest Editor
School of Materials Science and Engineering, Chonnam National University, Gwangju, South Korea
Interests: abnormal grain growth; lead-free piezoelectric ceramics; single crystal growth; sintering; barium hexaferrite; bioceramics

Special Issue Information

Dear Colleagues,

Sintering can be defined as the application of thermal energy to a shaped powder body to increase its strength by the formation of interparticle bonds and the elimination or control of porosity. Sintering is an essential step in the production of ceramics ranging from traditional applications such as porcelain and whitewares to high-performance applications such as bearings, microwave devices, fuel cells, capacitors, dental implants, and transducers. Although it is one of our oldest manufacturing technologies, sintering has only been studied scientifically since the 1940s. The two basic processes which take place during sintering are densification and grain growth. High density is desirable to improve the mechanical, electrical, and optical properties of ceramics. Grain size has a strong effect on the mechanical, electronic, magnetic, and optical properties of ceramics. Therefore, the control of both processes is vital in order to produce ceramics with the desired properties. This Special Issue will focus on sintering and grain growth behavior in ceramics, as well as on the relationship between microstructure and properties.

It is my pleasure to invite you to submit a manuscript to this Special Issue. I hope that this issue will gather together some of the latest and groundbreaking research on these topics. Manuscripts, both theoretical and experimental, concerning all types of sintering processes, ceramics, and applications are welcome. Full papers, communications, and reviews are all welcome.

Prof. Dr. John G. Fisher
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

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Keywords

  • sintering
  • densification
  • grain growth
  • microstructure–property relationship

Published Papers (3 papers)

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Research

Open AccessArticle
Development and Characterization of Titanium Dioxide Ceramic Substrates with High Dielectric Permittivities
Materials 2020, 13(2), 386; https://doi.org/10.3390/ma13020386 - 14 Jan 2020
Abstract
Titanium dioxide substrates have been synthesized by means of solid-state reactions with sintering temperatures varying from 1150 °C up to 1350 °C. X-ray diffraction and scanning electron microscopy (SEM) where employed to investigate the crystal structure, grain size and porosity of the resulting [...] Read more.
Titanium dioxide substrates have been synthesized by means of solid-state reactions with sintering temperatures varying from 1150 °C up to 1350 °C. X-ray diffraction and scanning electron microscopy (SEM) where employed to investigate the crystal structure, grain size and porosity of the resulting samples. The obtained ceramics are tetragonal (rutile phase) with average grain sizes varying from 2.94 µm up to 5.81 µm. The average grain size of samples increases with increasing temperature, while the porosity decreases. The effect of microstructure on the dielectric properties has been also studied. The reduction of porosity of samples significantly improves the dielectric parameters (relative dielectric permittivity and loss tangent) in comparison to those of commercial substrates, indicating that the obtained ceramic substrates could be useful in the miniaturization of telecommunication devices. Full article
(This article belongs to the Special Issue Sintering and Grain Growth Behavior of Ceramics)
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Open AccessFeature PaperArticle
Heterogeneity Challenges in Multiple-Element-Modified Lead-Free Piezoelectric Ceramics
Materials 2019, 12(24), 4049; https://doi.org/10.3390/ma12244049 - 05 Dec 2019
Abstract
We report on a heterogeneity study, down to the atomic scale, on a representative multiple-element-modified ceramic based on potassium sodium niobate (KNN): 0.95(Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3–0.05CaZrO3 with 2 wt % MnO2. [...] Read more.
We report on a heterogeneity study, down to the atomic scale, on a representative multiple-element-modified ceramic based on potassium sodium niobate (KNN): 0.95(Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O3–0.05CaZrO3 with 2 wt % MnO2. We show that different routes for incorporating the MnO2 (either before or after the calcination step) affect the phase composition and finally the functionality of the material. According to X-ray diffraction and scanning electron microscopy analyses, the ceramics consist of orthorhombic and tetragonal perovskite phases together with a small amount of Mn-rich secondary phase. The addition of MnO2 after the calcination results in better piezoelectric properties, corresponding to a ratio between the orthorhombic and tetragonal perovskite phases that is closer to unity. We also show, using microscopy techniques combined with analytical tools, that Zr-rich, Ta-rich and Mn-rich segregations are present on the nano and atomic levels. With this multi-scale analysis approach, we demonstrate that the functional properties are sensitive to minor modifications in the synthesis route, and consequently to different material properties on all scales. We believe that detecting and learning how to control these modifications will be a step forward in overcoming the irreproducibility problems with KNN-based materials. Full article
(This article belongs to the Special Issue Sintering and Grain Growth Behavior of Ceramics)
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Open AccessFeature PaperArticle
Effect of Composition on the Growth of Single Crystals of (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 by Solid State Crystal Growth
Materials 2019, 12(15), 2357; https://doi.org/10.3390/ma12152357 - 24 Jul 2019
Abstract
The (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs. electric field behaviour. Use of single crystals instead of polycrystalline ceramics may lead to further improvement in piezoelectric [...] Read more.
The (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs. electric field behaviour. Use of single crystals instead of polycrystalline ceramics may lead to further improvement in piezoelectric properties but work on single crystal growth in this system is limited. In particular, the effect of composition on single crystal growth has yet to be studied. In this work, single crystals of (NBT-100xST) with x = 0.00, 0.05, 0.10 and 0.20 were grown using the method of Solid State Crystal Growth. [001]-oriented SrTiO3 single crystal seeds were embedded in (NBT-100xST) ceramic powder, which was then pressed to form pellets and sintered at 1200 °C for 5 min–50 h. Single crystal growth rate, matrix grain growth rate and sample microstructure were examined using scanning and transmission electron microscopy. The results indicate that the highest single crystal growth rate was obtained at x = 0.20. The mixed control theory of grain growth is used to explain the single crystal and matrix grain growth behaviour. Full article
(This article belongs to the Special Issue Sintering and Grain Growth Behavior of Ceramics)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Micro-, nano- and atomic structure investigation of lkaline niobate based solid solutions

Oana Condurache1,2, Kristian Radan1, Mojca Otoničar1, Brigita Kmet1, Goran Dražić1,2,3, Barbara Malič1,2 and Andreja Benčan1,2

1Electronic Ceramics Department, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]

2 Jožef Sefan Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia

3 National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana Slovenia

Abstract: The market leading piezoelectric ceramics are, at the present moment, Pb(ZrxTi1-x)O3-based solid solutions. However, due to legislation and limitation of lead-based materials in commercial products [1], a big effort has-been put into study and development of more environmentally friendly alternatives. Sodium potassium niobate (KNN) based materials have been proved to be valid substitutes of lead-based piezoelectric ceramics. Construction of phase boundaries by chemical modification was proved to increase the piezoelectric activity with respect to pure KNN [2-4]. One of the approaches includes formation of solid solutions of KNN-based formulations with alkaline-earth perovskites, such as CaZrO3 (CZ) [5-6]. Moreover, NaNbO3 (NN), one of the end-members of KNN solid solution, is a prototype lead-free antiferroelectric, however, trace impurities or low applied electric fields may induce ferroelectricity. It has been shown that forming solid solutions of NN with CZ can be a strategy to stabilize the antiferroelectricity [7]. Such materials could then be used in energy storage. In the present study, we primarily focus on the microstructure, domain configuration and domain structure of selected alkaline niobate based solid solutions. Both Li,Ta and Mn-doped KNN-based solid solution with CZ, as a representative lead-free piezoceramic, and NN-CZ solid solution as a lead-free antiferroelectric are considered.

 References:

[1] Bell, A.J.; Deubzer, O. Lead-free piezoelectrics-The environmental and regulatory issues. MRS Bull. 2018, 43, 581–587

[2] Yasuyoshi Saito, Hisaaki Takao, Toshihiko Tani, Tatsuhiko Nonoyama, Kazumasa Takatori, Takahiko Homma, Toshiatsu Nagaya, and Masaya Nakamura. Lead-free piezoceramics. Nature 2004, 432, 84–87

[3] Xiaopeng Wang, Jiagang Wu, Dingquan Xiao, Jianguo Zhu, Xiaojing Cheng, Ting Zheng, Binyu Zhang, Xiaojie Lou, and Xiangjian Wang. Giant Piezoelectricity in Potassium-Sodium Niobate Lead-Free Ceramics. J. Am. Chem. Soc. 2014, 136, 2905−2910

[4] Jiagang Wu, Dingquan Xiao, and Jianguo Zhu. Potassium-Sodium Niobate Lead-Free Piezoelectric Materials: Past, Present, and Future of Phase Boundaries. Chem. Rev. 2015, 115, 2559−2595

[5] Ke Wang, Fang-Zhou Yao, Wook Jo, Danka Gobeljic , Vladimir V. Shvartsman, Doru C. Lupascu, Jing-Feng Li, and Jürgen Rödel. Temperature-

Insensitive (K,Na)NbO3-Based Lead-Free Piezoactuator Ceramics. Adv. Funct. Mater. 2013, 23, 4079–4086

[6] Kristian Radan, Brigita Kmet, Silvo Drnovšek, Uroš Prah , Tadej Rojac, and Barbara Malič. Mechanochemically-Assisted Synthesis of Lead-Free Piezoelectric CaZrO3-Modified (K,Na,Li)(Nb,Ta)O3-Solid Solution. Ceramics 2018, 1, 304–318

[7] Hanzheng Guo, Hiroyuki Shimizu, Youichi Mizuno, and Clive A. Randall. Domain configuration changes under electric field-induced antiferroelectricferroelectric phase transitions in NaNbO3-based ceramics. J. Appl. Phys. 2015, 118, 054102

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