Journal of the Ceramic Society of Japan
vol. 133, no.4, 2025
◆Full papers◆
Relaxation mechanism of interfacial lattice misfit between PZT and SRO in a thin-film actuator
https://doi.org/10.2109/jcersj2.24111
Shinsuke Hashimoto, Shun Kondo, Takehito Seki, Yuichi Ikuhara and Naoya Shibata
105
In thin-film actuators with PbZr1−xTixO3 (PZT)/SrRuO3 (SRO)/Pt layered structures, the SRO buffer layer shows favorable effects such as improved electrical properties and reduced oxygen vacancies in the PZT film. However, when the PZT composition becomes near the morphotropic phase boundary for enhanced piezoelectric properties, the lattice misfit of approximately 3 % should be formed at the PZT/SRO interface. Consequently, a mechanism to relax this lattice misfit should be required. Here, we investigated the lattice misfit relaxation mechanism using (Scanning) Transmission Electron Microscopy [(S)TEM]. We found that the lattice misfit was relaxed not only by the edge-type misfit dislocations at the interface but also by the twins in the SRO buffer layer. The twins in the SRO film form prior to the PZT film deposition, possibly due to the surface condition of the Pt substrate. These findings suggest that the Pt surface condition may affect the structure and properties of PZT/SRO/Pt.
Thermoelectric properties of BiBO3-added Bi2Sr2Co2Oy ceramics
https://doi.org/10.2109/jcersj2.24092
Nikoloz Margiani, Vakhtang Zhghamadze, Giorgi Mumladze, Masatoshi Takeda and Iamze Kvartskhava
112
The thermoelectric properties of BiBO3-added Bi2Sr2Co2Oy ceramics have been investigated. Bi2Sr2Co2Oy + x wt % BiBO3 materials (x = 0, 0.16, 0.50, and 0.80) were prepared by the sol–gel method. The values of power factor (PF) and figure of merit (ZT) were evaluated using electrical resistivity (ρ), Seebeck coefficient (S) and thermal conductivity (k) measurements. The Bi2Sr2Co2Oy + 0.16 wt % BiBO3 sample has the lowest ρ among all studied materials. The S rises with a rising temperature above 400 K, indicating p-type conductivity for each sample. The value of S for the reference (pristine) Bi2Sr2Co2Oy at 973 K is approximately 3–10 % higher than the BiBO3-added compositions. Reference and 0.16 wt % BiBO3-added samples exhibit higher PF values than those with higher BiBO3 content (x = 0.50 and 0.80). Adding bismuth borate (x > 0.16) leads to a 1.6-fold decrease in the thermal conductivity of the Bi2Sr2Co2Oy system at 573 K. The decrease of ρ (x = 0.16) and k (for all BiBO3-added compositions) resulted in a 39 % improvement in the ZT value.
Thermoluminescence properties of potassium-borosilicate glasses doped with Tb ion
https://doi.org/10.2109/jcersj2.24120
Shiyu Rim, Akihiro Nishikawa, Takumi Kato, Daisuke Nakauchi, Noriaki Kawaguchi and Takayuki Yanagida
117
We synthesized Tb-doped potassium borosilicate glasses using the melt-quenching method for application in personal dosimeters. Photoluminescence (PL) and thermoluminescence (TL) were observed and were attributed to the 4f-4f transitions of Tb3+ ions. The concentration dependence of PL and TL properties was investigated by varying the Tb concentration from 0 to 3.0 %. The quantum yield increased with rising Tb concentration. The PL decay time remained consistent across all Tb-doped samples with a typical value of ∼4.5 ms for Tb3+. The TL glow curves showed a glow peak at approximately 60 °C for all the samples. The 0.1 % sample showed the highest TL intensity. The dynamic range of the 0.1 % sample ranged from 0.01 mGy to 1 Gy.
β-SiAlON phosphor-in-glass mechanoluminescent materials for high-frequency mechanical sensing
https://doi.org/10.2109/jcersj2.24130
Yixi Zhuang, Long Chen, Rujun Yang, Wenli Liu, Changjian Chen, Jiaxing Guo, Jumpei Ueda, Jian Xu, Setsuhisa Tanabe, Yang Zhang and Rong-Jun Xie
124
The mechanical sensing technology based on mechanoluminescence (ML) shows several advantages such as remote response, stress distribution visualization and self-powering emission, which is expected to bring a breakthrough in the field of mechanical sensing. However, slow response and poor thermal stability are two major challenges in the ML-based sensing technology. In this work, an all-inorganic ML material β-SiAlON@glass was prepared by combining β-SiAlON (Si6−zAlzOzN8−z:Eu2+) phosphors with a low-melting-point glass. The β-SiAlON@glass showed the shortest ML lifetime of 9.8 µs reported so far, which was mainly due to the d-f electronic transition of Eu2+, very little persistent luminescence, and the high elastic modulus of the glass matrix. The β-SiAlON@glass exhibited excellent thermal stability with ML lifetime and peak intensity unchanged at temperatures up to 400 K. We revealed that the self-recoverable ML in the β-SiAlON@glass was primarily attributed to the triboelectric effect. Finally, we applied the β-SiAlON@glass to fabricate a ML sensor with a response time of 29 µs, which could clearly detect high-frequency ultrasonic waves at 25 kHz. The above results cannot only help us to further understand the mechanism in ML materials, but also provide an useful guidance for the development of high-performance ML sensors.
Effects of various nucleating agents on the crystallization and properties of lithium disilicate glass-ceramics
https://doi.org/10.2109/jcersj2.24122
Pei Zhang, Chenzhe Zhu, Yongchun Fan, Haixiang Wang, Cui Cui Wang, Jianfeng Zhu and Xiaohua Zhang
131
P2O5 is an efficacious nucleating agent for promoting the crystallization of lithium disilicate glass, with numerous studies attributing its effectiveness to the formation of Li3PO4 crystals, which serve as heterogeneous nucleation sites for Li2Si2O5 precipitation. However, recent studies have not consistently observed Li3PO4 precipitation. To address this controversy, this study utilizes Li3PO4 as a nucleating agent to determine whether Li3PO4 crystallites induce the precipitation of Li2Si2O5. Additionally, Na3PO4, an analogue of Li3PO4, is employed to evaluate its potential to promote nucleation, while P2O5 serves as a comparative reference under identical conditions. Upon heating, all three agents fully melt in the glass. Subsequent heat treatment results in the precipitation of Li2SiO3 crystals, followed by Li2Si2O5 crystals. It remains unclear whether these phosphates precipitate prior to the Li2SiO3 crystals. Although all agents exhibit comparable effects, the Li2Si2O5 grain size in the Na3PO4 group is finer, leading to decreased strength and increased transparency in the samples. This may be due to the mixed alkali effect, where Na+ ions inhibit the growth of Li2Si2O5 crystals. Notably, the initially precipitated Li2SiO3 crystals exhibit a higher Li content than the original glass, indicating that the nucleating agents alter the local glass composition to resemble that of the Li2SiO3 crystals, thereby facilitating crystallization. Subsequently, Li2SiO3 crystals decompose to form Li2Si2O5 crystals, resulting in a redistribution of Li+ ions from localized enrichment back to a uniform distribution consistent with the original glass.
Preparation and performance evaluation of monetite-type bone paste containing gelatinized starch
https://doi.org/10.2109/jcersj2.25019
Ryuga Ueno, Santa Kanda and Takahiro Kawai
139
Bone fillers are used for bone defects caused by injury or disease. One type of such a bone replacement material is a bone cement that hardens by mixing calcium phosphates powder in a physiological environment. We have prepared gelatinized starch-containing bone pastes that harden by forming hydroxyapatite [HAp; Ca10(PO4)6(OH)2] while providing excellent handling property by mixing the powder and a gelatinized wheat starch. In this study, a starch-containing monetite-type bone paste was prepared by kneading bioabsorbable and biocompatible anhydrous calcium hydrogen phosphate (DCPA; CaHPO4) powder with the gelatinized starch, and its properties were compared with those of the starch-containing HAp-type paste. The operability of the monetite-type paste samples was poor than that of HAp-type paste. In terms of crystalline phase, the monetite-type paste showed slightly different peak patterns attributed to DCPA before and after hardening, suggesting dissolution and reprecipitation of DCPA during soaking to set, while the HAp-type paste formed mainly HAp with trace amount of residual tetracalcium phosphate. Initial setting time of the monetite-type paste was longer than that of HAp-type one. Compressive strength exceeded 40 MPa for both of the sample types. In vitro bioabsorbability of the monetite-type paste was higher than that of HAp-type one. Furthermore, the hydrophilicity of the monetite-type paste was higher than that of HAp-type one. This suggests that starch-containing monetite-type bone pastes are expected to be partially replaced by autogenous bone as the hardened material is resorbed in vivo.
Effect of magnesium on β-α phase transformation of wollastonite
https://doi.org/10.2109/jcersj2.25020
Natsuki Hosoya and Hirotaka Fujimori
145
Wollastonite is a calcium silicate (CaSiO3) which has been widely studied as a ceramic raw material with its mechanical, insulative and bioactive properties. Since wollastonite undergoes crystal phase transition from β-CaSiO3 to α-CaSiO3, it is important to investigate the relationship between phase transition and material properties of wollastonite. In this study, Mg-doped wollastonite (β-Ca1−xMgxSiO3) was synthesized, and quantitative phase analysis was conducted to reveal the effect of Mg on β-α phase transformation. As a result, when the phase transformation occurs at 1250 and 1300 °C, Mg dissolve in β-CaSiO3 up to the solid solubility limits, forming β-Ca0.94Mg0.06SiO3 and β-Ca0.90Mg0.10SiO3, respectively. Additionally, since Mg hardly dissolves in α-CaSiO3, the diffusion of Mg outward from β-CaSiO3 crystal lattices slows down the rate of β-α phase transformation.
Prediction of cross-material properties of mineralized ceramic core of aluminosilicate system based on deep learning
https://doi.org/10.2109/jcersj2.24107
Qing Zhu, Yikui Xie, Weidong Xuan, Songzhe Xu and Zhongming Ren
150
Silicon-based ceramic cores with aluminum silicate particles and fibers as mineralizers were prepared separately using the injection molding method. A comprehensive property evaluation model was proposed based on the physical property parameters of the ceramic cores, which were optimized using weight coefficients. A prediction model based on a backpropagation neural network was constructed to predict the effects of aluminum silicate fibers and particles as mineralizers on the properties of ceramic cores, and a properties optimization study on single materials were conducted. Additionally, a blending model was established to achieve cross-material properties predictions. The results indicate that the optimization predictions for single materials were more precise than those obtained through traditional experimental methods. The cross-material blending model identified an abnormal increase in the mean squared error at an addition amount of 1 wt.% aluminum silicate fibers, suggesting the presence of complex material behavior at this point. The full combination prediction results demonstrate that the neural network model performs well overall in predicting cross-material properties. The results of cross-material prediction show that the prediction results are in good agreement with the experimental measurement results, which indicate that the cross-material property parameter mapping and prediction of the neural network has good accuracy.
◆Technical reports◆
Oxygen content of α-silicon nitride powder depending on the synthesis method
https://doi.org/10.2109/jcersj2.24126
Osamu Matsumoto, Hiroshi Okamura and Mitsutaka Takahashi
161
Wet classification was carried out on α-silicon nitride powders prepared by different methods, and the amount of dissolved oxygen and surface oxygen was measured using carrier gas hot extraction method. As a result, the amount of surface oxygen varied systematically depending on the class. The thickness of the oxide layer estimated from the amount of surface oxygen was 0.2–0.5 nm, which was the same as the values reported by X-ray photoelectron spectroscopy and Auger electron spectroscopy. On the other hand, the amount of dissolved oxygen was almost constant regardless of the specific surface area. The powder prepared by direct nitridation method showed a lower amount of dissolved oxygen than the powders prepared by combustion synthesis method.
Functions of glycerol in the tape-casting process: Revealing with AFM colloid probe measurements
https://doi.org/10.2109/jcersj2.24112
Ryutaro Usukawa, Kimiyasu Sato, Yuji Hotta and Mikinori Hotta
166
The purpose of the present study is to reveal functions of organic additives utilized in tape casting, a key technique for ceramic manufacturing. Interaction forces between alumina surfaces were measured using colloid probe atomic force microscopy (AFM) in dilute aqueous solutions containing both or one of polyvinyl alcohol (PVA) and glycerol. PVA and glycerol are typical additives for tape casting and are used as a binder and a plasticizer, respectively. In the PVA solution, repulsive forces due to steric hindrance were observed at separation distance about 10 nm. The glycerol solution exhibited a combination of attractive and repulsive forces, with a strong attraction at around 20 nm, attributed to the depletion effect caused by striking hydration ability of glycerol. The mixed solution of PVA and glycerol showed an increased repulsion distance of approximately 30 nm, suggesting that glycerol interacts with PVA molecules, altering their molecular conformation and expanding their gyration radius. The results indicate that addition of glycerol not only imparts mechanical flexibility to the green sheets but also stabilizes the alumina slurry. The empirically selected and optimized organic additives could fulfill multiple functions to improve the ceramic forming processes. As is presented in the study, the AFM colloid probe measurements would contribute to the understanding of how organic additives work and the development of more sophisticated ceramic processing.
◆Errata◆
Crystal-oriented hydroxyapatite ceramic sheets tailored in a novel tape casting process of powder mixture system
https://doi.org/10.2109/jcersj2.2411402Yunzi Xin, Yasuyuki Murakami and Takashi Shirai
170
◆Announcement◆
Call for a Guest Editor for the Feature
https://doi.org/10.2109/jcersj2.133.A4-1A4-1
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