Pub Date : 2026-07-01Epub Date: 2026-01-27DOI: 10.1016/j.jeurceramsoc.2026.118166
Mengrui Li , Xianmeng Chen , Boon Xian Chai , Guibing Shi , M. Akbar Rhamdhani , Li Wang , Shanqing Xu
This study proposes a novel CaTiO3 (CTO) doping strategy for MnZn ferrites to co-incorporate Ca2+ and Ti4+ ions, aiming to develop low power loss magnetic materials for megahertz-range frequency applications. The effects of CaTiO3 doping on power loss, cut-off frequency, and microstructure were systematically examined. As compared with traditional CaO and TiO2 doping, CaTiO3 doping enabled more uniform dopant distribution, refined grain structure, and enhanced electrical resistivity. Among all samples, the MnZn ferrites doped with CTO achieved an 87.5 % reduction in power loss (155 mW/cm3 at 1 MHz/30 mT/25 °C) relative to the undoped reference, while maintaining excellent magnetic performance. Loss separation analysis revealed that the major contribution to this improvement was the suppression of eddy current loss (Pe), complemented by reductions in hysteresis (Ph). This work demonstrates the great potential of CaTiO3 as a cost-effective, scalable, and efficient dopant for enhancing the high-frequency performance of MnZn ferrites in next-generation power electronics.
{"title":"Introduction of Ca2+ and Ti4+ ions by a novel additive CaTiO3 for manufacturing low power loss MnZn ferrites","authors":"Mengrui Li , Xianmeng Chen , Boon Xian Chai , Guibing Shi , M. Akbar Rhamdhani , Li Wang , Shanqing Xu","doi":"10.1016/j.jeurceramsoc.2026.118166","DOIUrl":"10.1016/j.jeurceramsoc.2026.118166","url":null,"abstract":"<div><div>This study proposes a novel CaTiO<sub>3</sub> (CTO) doping strategy for MnZn ferrites to co-incorporate Ca<sup>2+</sup> and Ti<sup>4+</sup> ions, aiming to develop low power loss magnetic materials for megahertz-range frequency applications. The effects of CaTiO<sub>3</sub> doping on power loss, cut-off frequency, and microstructure were systematically examined. As compared with traditional CaO and TiO<sub>2</sub> doping, CaTiO<sub>3</sub> doping enabled more uniform dopant distribution, refined grain structure, and enhanced electrical resistivity. Among all samples, the MnZn ferrites doped with CTO achieved an 87.5 % reduction in power loss (155 mW/cm<sup>3</sup> at 1 MHz/30 mT/25 °C) relative to the undoped reference, while maintaining excellent magnetic performance. Loss separation analysis revealed that the major contribution to this improvement was the suppression of eddy current loss (<em>P</em><sub><em>e</em></sub>), complemented by reductions in hysteresis (<em>P</em><sub><em>h</em></sub>). This work demonstrates the great potential of CaTiO<sub>3</sub> as a cost-effective, scalable, and efficient dopant for enhancing the high-frequency performance of MnZn ferrites in next-generation power electronics.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118166"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research presents a novel UV-assisted drop casting approach for shaping ceramic microbeads from aqueous-based UV-curable alumina suspensions. The work focused on optimising suspension composition and shaping conditions to obtain dense microbeads with high sphericity. The effects of dispersant concentration, solid loading, monomer ratio, and photoinitiator content on rheology and UV curing were systematically investigated. The optimal suspension (42.5 vol% alumina; water:2-hydroxyethyl acrylate:poly(propylene glycol) dimethacrylate ratio 10:9:1; 5 wt% dispersant; 0.5 wt% photoinitiator) showed shear-thinning behaviour and a cure depth of 580 µm. Shaped droplets were UV-cured in a hydrophobic medium, and thermal analysis enabled controlled debinding and sintering. The best series yielded beads with an average diameter of 1262 µm, circularity up to 0.99, and low dimensional variability. Dense microstructures with minimal porosity were achieved, though surface delamination and grain coarsening occurred. The method enables efficient fabrication of spherical ceramic elements with high structural integrity.
{"title":"UV-assisted drop casting as a novel technique in fabrication of dense ceramic microbeads","authors":"Radoslaw Zurowski , Blanka Seredynska , Karolina Korycka , Aleksandra Szewczyk , Zofia Skowronska , Zofia Kostrzewska , Wiktor Drab , Joanna Tanska , Dominik Wolosz , Anna Wieclaw-Midor , Piotr Wiecinski , Justyna Zygmuntowicz , Dawid Kozien , Paulina Wiecinska , Gustavo Suárez , Pawel Falkowski","doi":"10.1016/j.jeurceramsoc.2026.118161","DOIUrl":"10.1016/j.jeurceramsoc.2026.118161","url":null,"abstract":"<div><div>This research presents a novel UV-assisted drop casting approach for shaping ceramic microbeads from aqueous-based UV-curable alumina suspensions. The work focused on optimising suspension composition and shaping conditions to obtain dense microbeads with high sphericity. The effects of dispersant concentration, solid loading, monomer ratio, and photoinitiator content on rheology and UV curing were systematically investigated. The optimal suspension (42.5 vol% alumina; water:2-hydroxyethyl acrylate:poly(propylene glycol) dimethacrylate ratio 10:9:1; 5 wt% dispersant; 0.5 wt% photoinitiator) showed shear-thinning behaviour and a cure depth of 580 µm. Shaped droplets were UV-cured in a hydrophobic medium, and thermal analysis enabled controlled debinding and sintering. The best series yielded beads with an average diameter of 1262 µm, circularity up to 0.99, and low dimensional variability. Dense microstructures with minimal porosity were achieved, though surface delamination and grain coarsening occurred. The method enables efficient fabrication of spherical ceramic elements with high structural integrity.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118161"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-15DOI: 10.1016/j.jeurceramsoc.2026.118147
Chengming Li , Lang Bian , Jianhui Jia , Shangpeng Yang , Kai Li , Pengrong Ren
The introduction of oxygen vacancies and defect dipoles to induce giant bending strain is a cutting-edge strategy to improve the performance of piezoelectric ceramics. However, its feasibility in a more widely used multi-layer structure is still unknown. In this study, it is found that the giant strain successfully achieved in single-layer ceramics almost disappeared in multi-layer ceramics based on the same material system. The system analysis shows that the internal mechanical clamping effect introduced by the multi-layer structure and the opposite bending direction between adjacent layers are the root causes of large strain failure. The conclusion of this study clearly points out that the excellent piezoelectric properties in unconstrained single-layer samples cannot be directly converted into the actual advantages of multi-layer devices. This finding provides a crucial application perspective correction for the current popular defect engineering research.
{"title":"Giant strain vanishes in multilayer ceramics: The limitation of defect-dipole engineering","authors":"Chengming Li , Lang Bian , Jianhui Jia , Shangpeng Yang , Kai Li , Pengrong Ren","doi":"10.1016/j.jeurceramsoc.2026.118147","DOIUrl":"10.1016/j.jeurceramsoc.2026.118147","url":null,"abstract":"<div><div>The introduction of oxygen vacancies and defect dipoles to induce giant bending strain is a cutting-edge strategy to improve the performance of piezoelectric ceramics. However, its feasibility in a more widely used multi-layer structure is still unknown. In this study, it is found that the giant strain successfully achieved in single-layer ceramics almost disappeared in multi-layer ceramics based on the same material system. The system analysis shows that the internal mechanical clamping effect introduced by the multi-layer structure and the opposite bending direction between adjacent layers are the root causes of large strain failure. The conclusion of this study clearly points out that the excellent piezoelectric properties in unconstrained single-layer samples cannot be directly converted into the actual advantages of multi-layer devices. This finding provides a crucial application perspective correction for the current popular defect engineering research.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 7","pages":"Article 118147"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-18DOI: 10.1016/j.jeurceramsoc.2026.118155
Lu Zhu , Nana Zhu , Pengju Tang , Baojing Zhang , Shengyuan Lei , Xiaohong Wang , Peizhong Feng
MoSi2‑based ceramics with superior high‑temperature nitridation resistance were developed through a dual strategy combining Al alloying and pre‑oxidation. A two-step route, self-propagating high-temperature synthesis followed by spark plasma sintering, was employed to prepare MoSi2 and Al-alloyed Mo(Si0.95Al0.05)2. Al incorporation and pre‑oxidation at 1500 °C produced dense Al–Si–O composite scales that merged the impermeability of SiO2 with the thermal stability of Al2O3. During direct nitridation at 1200 °C, the nitrogen diffusion coefficients of Mo(Si0.95Al0.05)2 decreased by 76% and 82% in the rapid (0–16 h) and slow (16–64 h) stages, and its overall mass change was much lower than that of MoSi2. Pre‑oxidation further enhanced protection, reducing diffusion coefficients to 0.005 and 0.001 mg/cm2·h0.5 compared with MoSi2 (0.007 and 0.004 mg/cm2·h0.5), due to the formation of stable Al–Si–O scales. Therefore, the pioneering dual strategy demonstrates a novel approach for developing advanced MoSi2-based ceramics with outstanding high-temperature nitridation resistance.
{"title":"Dual strategy to enhance the nitridation resistance of MoSi2-based ceramics for high-temperature applications","authors":"Lu Zhu , Nana Zhu , Pengju Tang , Baojing Zhang , Shengyuan Lei , Xiaohong Wang , Peizhong Feng","doi":"10.1016/j.jeurceramsoc.2026.118155","DOIUrl":"10.1016/j.jeurceramsoc.2026.118155","url":null,"abstract":"<div><div>MoSi<sub>2</sub>‑based ceramics with superior high‑temperature nitridation resistance were developed through a dual strategy combining Al alloying and pre‑oxidation. A two-step route, self-propagating high-temperature synthesis followed by spark plasma sintering, was employed to prepare MoSi<sub>2</sub> and Al-alloyed Mo(Si<sub>0.95</sub>Al<sub>0.05</sub>)<sub>2</sub>. Al incorporation and pre‑oxidation at 1500 °C produced dense Al–Si–O composite scales that merged the impermeability of SiO<sub>2</sub> with the thermal stability of Al<sub>2</sub>O<sub>3</sub>. During direct nitridation at 1200 °C, the nitrogen diffusion coefficients of Mo(Si<sub>0.95</sub>Al<sub>0.05</sub>)<sub>2</sub> decreased by 76% and 82% in the rapid (0–16 h) and slow (16–64 h) stages, and its overall mass change was much lower than that of MoSi<sub>2</sub>. Pre‑oxidation further enhanced protection, reducing diffusion coefficients to 0.005 and 0.001 mg/cm<sup>2</sup>·h<sup>0.5</sup> compared with MoSi<sub>2</sub> (0.007 and 0.004 mg/cm<sup>2</sup>·h<sup>0.5</sup>), due to the formation of stable Al–Si–O scales. Therefore, the pioneering dual strategy demonstrates a novel approach for developing advanced MoSi<sub>2</sub>-based ceramics with outstanding high-temperature nitridation resistance.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118155"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-17DOI: 10.1016/j.jeurceramsoc.2026.118143
Jae-Min Cha , Cheol-Woo Ahn , Hyun-Ae Cha , Byung-Dong Hahn , Woon-Ha Yoon , Young Kook Moon , Seog-Young Yoon , Jong-Jin Choi
Textured Pb[(Mg0.5Ni0.5)1/3Nb2/3]O3-PbZrTiO3 (PMNN–PZT) piezoelectric ceramics were fabricated by the templated grain growth (TGG) method. Plate-like Ba(Zr0.1Ti0.9)O3 (BZT) templates were synthesized by topochemical molten salt synthesis (TMSS) and employed to promote grain orientation. Compared with conventional BaTiO3 (BT) templates, BZT templates exhibited lower reactivity with the matrix, resulting in a reduced tetragonal phase shift and a higher Lotgering factor after texturing. The phase composition of PMNN–PZT was further optimized to the morphotropic phase boundary (MPB) region by adjusting the Zr/Ti ratio. The textured ceramics thus obtained exhibited both a high piezoelectric charge coefficient (d₃₃ ∼ 610 pC/N) and a high mechanical quality factor (Qm ∼1145), overcoming the typical trade-off between these properties. These findings demonstrate that BZT templating is an effective strategy for tailoring phase composition and enhancing the electromechanical performance of textured piezoelectric ceramics.
{"title":"Giant piezoelectric properties in hard-type PMNN-PZT ceramics via templated grain growth using BZT templates","authors":"Jae-Min Cha , Cheol-Woo Ahn , Hyun-Ae Cha , Byung-Dong Hahn , Woon-Ha Yoon , Young Kook Moon , Seog-Young Yoon , Jong-Jin Choi","doi":"10.1016/j.jeurceramsoc.2026.118143","DOIUrl":"10.1016/j.jeurceramsoc.2026.118143","url":null,"abstract":"<div><div>Textured Pb[(Mg<sub>0.5</sub>Ni<sub>0.5</sub>)<sub>1/3</sub>Nb<sub>2/3</sub>]O<sub>3</sub>-PbZrTiO<sub>3</sub> (PMNN–PZT) piezoelectric ceramics were fabricated by the templated grain growth (TGG) method. Plate-like Ba(Zr<sub>0.1</sub>Ti<sub>0.9</sub>)O<sub>3</sub> (BZT) templates were synthesized by topochemical molten salt synthesis (TMSS) and employed to promote grain orientation. Compared with conventional BaTiO<sub>3</sub> (BT) templates, BZT templates exhibited lower reactivity with the matrix, resulting in a reduced tetragonal phase shift and a higher Lotgering factor after texturing. The phase composition of PMNN–PZT was further optimized to the morphotropic phase boundary (MPB) region by adjusting the Zr/Ti ratio. The textured ceramics thus obtained exhibited both a high piezoelectric charge coefficient (<em>d</em>₃₃ ∼ 610 pC/N) and a high mechanical quality factor (<em>Q</em><sub>m</sub> ∼1145), overcoming the typical trade-off between these properties. These findings demonstrate that BZT templating is an effective strategy for tailoring phase composition and enhancing the electromechanical performance of textured piezoelectric ceramics.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118143"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-20DOI: 10.1016/j.jeurceramsoc.2026.118148
Shixiang Zhou , Zhuofeng Peng , Chunze Yan , Yusheng Shi
The molecular engineering of dispersants plays a critical role in addressing the rheological challenges associated with high solid loading and printability in slurry-based ceramic 3D printing. This review establishes a systematic framework of "dispersant architecture-colloidal state-rheology-sintered performance" to guide the selection and design of dispersants for vat photopolymerization (VPP) and direct ink writing (DIW), which are the dominant slurry-based ceramic 3D printing techniques. The discussion begins with a comparison of the technical characteristics between VPP- and DIW- based ceramic 3D printing, including the forming process, and applications, with a specific emphasis on the different rheological requirements. We further elucidate dispersant design strategies by discussing dispersion mechanism, classification, modification, and characterization methods. The review then highlights how dispersant molecular structure governs rheological behavior, printability, and green-body and sintered properties, enabling tailored performance for structural and functional applications. Finally, this review summarizes dispersant selection criteria and addresses both existing challenges and potential directions for future research.
{"title":"Molecular engineering of dispersants for tailoring rheology in slurry-based ceramic 3D printing: From colloidal control to sintered performance","authors":"Shixiang Zhou , Zhuofeng Peng , Chunze Yan , Yusheng Shi","doi":"10.1016/j.jeurceramsoc.2026.118148","DOIUrl":"10.1016/j.jeurceramsoc.2026.118148","url":null,"abstract":"<div><div>The molecular engineering of dispersants plays a critical role in addressing the rheological challenges associated with high solid loading and printability in slurry-based ceramic 3D printing. This review establishes a systematic framework of \"dispersant architecture-colloidal state-rheology-sintered performance\" to guide the selection and design of dispersants for vat photopolymerization (VPP) and direct ink writing (DIW), which are the dominant slurry-based ceramic 3D printing techniques. The discussion begins with a comparison of the technical characteristics between VPP- and DIW- based ceramic 3D printing, including the forming process, and applications, with a specific emphasis on the different rheological requirements. We further elucidate dispersant design strategies by discussing dispersion mechanism, classification, modification, and characterization methods. The review then highlights how dispersant molecular structure governs rheological behavior, printability, and green-body and sintered properties, enabling tailored performance for structural and functional applications. Finally, this review summarizes dispersant selection criteria and addresses both existing challenges and potential directions for future research.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118148"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Porous alumina ceramics are fabricated using the sacrificial template method to investigate the impact of two different sphere sizes, PMMA porogen ( of 80 and 163 µm) and volume fraction (up to 76 vol%) on material properties. In order to screen the viable parameter space (where samples are mechanically resistant and permeable) efficiently and to leverage the possibility to manufacture several samples in parallel, a batch active learning algorithm coupled with a data-driven model based on Gaussian process classification is developed. Complementary, a Gaussian process regression (GPR) model is developed to predict permeability trends across the viable parametric space. Both models are tested and blind-validated experimentally using unseen data. The combination of GPC and active learning offers a powerful tool for generating effective experimental plans, particularly when investigating processes with large parametric spaces.
{"title":"Active learning-assisted experimental design for porous ceramic manufacturing","authors":"Jnanesh Gopale Gowda, Liam Latour, Paul Baral, Renaud Ferrier, Sébastien Saunier","doi":"10.1016/j.jeurceramsoc.2025.118116","DOIUrl":"10.1016/j.jeurceramsoc.2025.118116","url":null,"abstract":"<div><div>Porous alumina ceramics are fabricated using the sacrificial template method to investigate the impact of two different sphere sizes, PMMA porogen (<span><math><msub><mrow><mi>D</mi></mrow><mrow><mn>50</mn></mrow></msub></math></span> of 80 and 163 µm) and volume fraction (up to 76 vol%) on material properties. In order to screen the viable parameter space (where samples are mechanically resistant and permeable) efficiently and to leverage the possibility to manufacture several samples in parallel, a batch active learning algorithm coupled with a data-driven model based on Gaussian process classification is developed. Complementary, a Gaussian process regression (GPR) model is developed to predict permeability trends across the viable parametric space. Both models are tested and blind-validated experimentally using unseen data. The combination of GPC and active learning offers a powerful tool for generating effective experimental plans, particularly when investigating processes with large parametric spaces.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 7","pages":"Article 118116"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2025-12-18DOI: 10.1016/j.jeurceramsoc.2025.118100
Zelai Cheng , Yulan Jing , Xi Wang , Feng Qiao , Xiuling Yang , Ying Chen , Mingshan Qu , Hua Su
The escalating demand for miniaturized high-frequency circulators in radar and satellite systems necessitates ferrite materials that concurrently possess a high saturation magnetization (4πMs), a narrow ferromagnetic resonance linewidth (ΔH), and a high dielectric constant (εr). In this study, a defect-engineered Bi1.4Ca0.3Zr0.3Y1.3Fe4.6−xIn0.1O12−δ garnet ferrite was synthesized, in which synergistic Zr⁴⁺/In³ ⁺ dual-site doping and controlled Fe-vacancies improved magnetic performance. At optimal Fe-deficiency (x = 0.1), the material achieved a high 4πMs of around 2001 G, enabling C-X band operation. Simultaneously, it attained narrow ferromagnetic resonance linewidth (ΔH ≈ 112 Oe) through reduced magnetocrystalline anisotropy (|K1|) and an enhanced dielectric constant (εr ≈ 26.2) via the “rattling” effect that compensated for vacancy-induced polarization loss. A straight-circuit microstrip circulator based on this ferrite (r0 = 2.14 mm, r1 = 7.76 mm) was operated in the bandwidth from 4.23 to 9.85 GHz. It exhibited insertion loss (S21) better than −0.5 dB and isolation/return loss (S11/S12) below −20 dB. A curved-microstrip redesign further reduced the substrate area to 28.7 % of the original while maintaining operation from 4.34 to 9.36 GHz, demonstrating exceptional potential for compact C-X band circulators.
{"title":"Fe-vacancy-modified Bi-YIG ferrites with high saturation magnetization and high dielectric constant for miniaturization of C-X band circulators","authors":"Zelai Cheng , Yulan Jing , Xi Wang , Feng Qiao , Xiuling Yang , Ying Chen , Mingshan Qu , Hua Su","doi":"10.1016/j.jeurceramsoc.2025.118100","DOIUrl":"10.1016/j.jeurceramsoc.2025.118100","url":null,"abstract":"<div><div>The escalating demand for miniaturized high-frequency circulators in radar and satellite systems necessitates ferrite materials that concurrently possess a high saturation magnetization (4π<em>M</em><sub><em>s</em></sub>), a narrow ferromagnetic resonance linewidth (<em>ΔH</em>), and a high dielectric constant (<em>ε</em><sub><em>r</em></sub>). In this study, a defect-engineered Bi<sub>1.4</sub>Ca<sub>0.3</sub>Zr<sub>0.3</sub>Y<sub>1.3</sub>Fe<sub>4.6−x</sub>In<sub>0.1</sub>O<sub>12−δ</sub> garnet ferrite was synthesized, in which synergistic Zr⁴⁺/In³ ⁺ dual-site doping and controlled Fe-vacancies improved magnetic performance. At optimal Fe-deficiency (x = 0.1), the material achieved a high 4π<em>M</em><sub><em>s</em></sub> of around 2001 G, enabling C-X band operation. Simultaneously, it attained narrow ferromagnetic resonance linewidth (<em>ΔH</em> ≈ 112 Oe) through reduced magnetocrystalline anisotropy (|<em>K</em><sub><em>1</em></sub>|) and an enhanced dielectric constant (<em>ε</em><sub><em>r</em></sub> ≈ 26.2) via the “rattling” effect that compensated for vacancy-induced polarization loss. A straight-circuit microstrip circulator based on this ferrite (<em>r</em><sub><em>0</em></sub> = 2.14 mm, <em>r</em><sub><em>1</em></sub> = 7.76 mm) was operated in the bandwidth from 4.23 to 9.85 GHz. It exhibited insertion loss (<em>S</em><sub><em>21</em></sub>) better than −0.5 dB and isolation/return loss (<em>S</em><sub><em>11</em></sub>/<em>S</em><sub><em>12</em></sub>) below −20 dB. A curved-microstrip redesign further reduced the substrate area to 28.7 % of the original while maintaining operation from 4.34 to 9.36 GHz, demonstrating exceptional potential for compact C-X band circulators.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 7","pages":"Article 118100"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The pursuit of high-performance lead-free dielectric capacitors has increasingly focused on compositional complexity and advanced processing techniques. In this work, a ternary high-entropy ceramic system, (1–)(0.7BiFeO3–0.3BaTi0.8Zr0.2O3)–NaTaO3 ( = 0, 0.05, 0.10, 0.15, and 0.2), was synthesized to investigate the role of configurational entropy (Sconfig) in enhancing performance stability and energy storage. The = 0.10 sample via conventional sintering (CS) process achieves a high recoverable energy density (Wrec) of 10.8 J/cm3 and an efficiency (η) of 78.8 % at an electric field of 550 kV/cm. In addition, the = 0.10 sample via microwave sintering (MWS) demonstrates a Wrec of 12.6 J/cm3 with a η of 79.5 % at an electric field of 600 kV/cm, resulting from the rapid volumetric heating, effectively reduced porosity and preserved volatile constituents. This study highlights an effective entropy-driven design, combined with rapid microwave sintering for promoting energy storage capability in lead-free dielectric materials.
{"title":"Achieving high-energy storage via microwave sintering-assisted BiFeO3–BaTi0.8Zr0.2O3–NaTaO3 relaxor ferroelectrics","authors":"Shu-Yu Chen , Kuei-Chih Feng , R.R. Chien , Haidee Mana-ay , Cheng-Sao Chen , Chi-Shun Tu , Pin-Yi Chen","doi":"10.1016/j.jeurceramsoc.2026.118139","DOIUrl":"10.1016/j.jeurceramsoc.2026.118139","url":null,"abstract":"<div><div>The pursuit of high-performance lead-free dielectric capacitors has increasingly focused on compositional complexity and advanced processing techniques. In this work, a ternary high-entropy ceramic system, (1–<span><math><mi>x</mi></math></span>)(0.7BiFeO<sub>3</sub>–0.3BaTi<sub>0.8</sub>Zr<sub>0.2</sub>O<sub>3</sub>)–<span><math><mi>x</mi></math></span>NaTaO<sub>3</sub> (<span><math><mi>x</mi></math></span> = 0, 0.05, 0.10, 0.15, and 0.2), was synthesized to investigate the role of configurational entropy (<em>S</em><sub><em>config</em></sub>) in enhancing performance stability and energy storage. The <span><math><mi>x</mi></math></span> = 0.10 sample via conventional sintering (CS) process achieves a high recoverable energy density (<em>W</em><sub><em>rec</em></sub>) of 10.8 J/cm<sup>3</sup> and an efficiency (<em>η</em>) of 78.8 % at an electric field of 550 kV/cm. In addition, the <span><math><mi>x</mi></math></span> = 0.10 sample via microwave sintering (MWS) demonstrates a <em>W</em><sub><em>rec</em></sub> of 12.6 J/cm<sup>3</sup> with a η of 79.5 % at an electric field of 600 kV/cm, resulting from the rapid volumetric heating, effectively reduced porosity and preserved volatile constituents. This study highlights an effective entropy-driven design, combined with rapid microwave sintering for promoting energy storage capability in lead-free dielectric materials.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 7","pages":"Article 118139"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-07-01Epub Date: 2026-01-27DOI: 10.1016/j.jeurceramsoc.2026.118172
Julian Fanghanel , Satoshi Yokomizo , Shuichi Funahashi , Jeffrey Shallenberger , Ke Wang , Sophie Guillemet-Fritsch , Clive A. Randall
Cold sintering using eutectic molten salts transient chemistries presents a promising low-temperature route for fabricating NiMn2O4 based NTC thermistors without the need for conventional high-temperature sintering. In this work, we explore the use of a LiCl–LiI flux to densify NiMn2O4 at just 400 °C, achieving > 95 % relative density and preserving the spinel with minor impurities that are largely erased after a brief post anneal at 850 °C. While initial electrical properties of the cold-sintered parts are influenced by a flux-mediated reduction and cation inversion segregation, we show that a mild anneal at 850 °C is sufficient to restore a more stable thermistor. Here we argue that the transient phase of LiCl–LiI drives a cation-Frenkel–dominated reduction during the densification: transient dissolution/precipitation and halide redox promote formation of metal interstitials (Nii,Mni) paired with cation vacancies on the normal sublattices, with a valence shifts (Mn4+→Mn3+). We also report that, in the absence of annealing, these samples undergo a negative aging with a decrease in resistance over time, further supporting the role of the flux modifying the oxidation state and site occupancy. These results demonstrate that cold sintering, when paired with strategic annealing, can produce high thermistor performance with a thermally stable NTC ceramics at a fraction of the processing energy and temperature, with tunable electrical properties driven by the molten salt flux chemistry.
{"title":"Cold-sintered NiMn2O4 thermistors: An electrical aging and recovery study","authors":"Julian Fanghanel , Satoshi Yokomizo , Shuichi Funahashi , Jeffrey Shallenberger , Ke Wang , Sophie Guillemet-Fritsch , Clive A. Randall","doi":"10.1016/j.jeurceramsoc.2026.118172","DOIUrl":"10.1016/j.jeurceramsoc.2026.118172","url":null,"abstract":"<div><div>Cold sintering using eutectic molten salts transient chemistries presents a promising low-temperature route for fabricating NiMn<sub>2</sub>O<sub>4</sub> based NTC thermistors without the need for conventional high-temperature sintering. In this work, we explore the use of a LiCl–LiI flux to densify NiMn<sub>2</sub>O<sub>4</sub> at just 400 °C, achieving > 95 % relative density and preserving the spinel with minor impurities that are largely erased after a brief post anneal at 850 °C. While initial electrical properties of the cold-sintered parts are influenced by a flux-mediated reduction and cation inversion segregation, we show that a mild anneal at 850 °C is sufficient to restore a more stable thermistor. Here we argue that the transient phase of LiCl–LiI drives a cation-Frenkel–dominated reduction during the densification: transient dissolution/precipitation and halide redox promote formation of metal interstitials (Ni<sub>i</sub>,Mn<sub>i</sub>) paired with cation vacancies on the normal sublattices, with a valence shifts (Mn<sup>4</sup><sup>+</sup>→Mn<sup>3+</sup>). We also report that, in the absence of annealing, these samples undergo a negative aging with a decrease in resistance over time, further supporting the role of the flux modifying the oxidation state and site occupancy. These results demonstrate that cold sintering, when paired with strategic annealing, can produce high thermistor performance with a thermally stable NTC ceramics at a fraction of the processing energy and temperature, with tunable electrical properties driven by the molten salt flux chemistry.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"46 8","pages":"Article 118172"},"PeriodicalIF":6.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号