Pub Date : 2026-01-01DOI: 10.1016/j.ceramint.2025.12.144
Nejib Ghazouani , Abdelatif Salmi , Ahmed A. Alawi Al-Naghi , Khaled Mohamed Elhadi , Ali Raza
This study evaluates the engineering properties of ultra-high-performance green cement composites (UHPGC) made with municipal solid waste incineration fly ash (MFA). Five mix designs were prepared using a constant w/b ratio of 0.17 and 70 % Portland cement with 30 % supplementary cementitious materials. The mixes included binary systems with silica fume (SF), metakaolin (MK), or MFA and ternary blends with SF-MK or SF-MFA. All specimens were cast in 50 × 100 mm cylinders and 40 × 40 × 160 mm prisms. All mixes were thermally cured at 60 °C for 48 h. Tests included workability, density, compressive strength, modulus of elasticity, capillary water absorption, and drying shrinkage. Microstructural analysis was done using SEM/EDS, XRD, and TGA/DTG. One-way ANOVA and Tukey's HSD were used to check significance. MFA increased workability by 36.11 % because of its low intra-particle absorption. All mixes achieved compressive strengths above 100 MPa. The SF-rich mix reached 134.5 MPa at 28 days while the MFA mix reached 109.3 MPa. The ternary mixes showed balanced strength and workability with strengths of 129.2–129.9 MPa. The highest density was 2368 kg/m3 in the MK mix. The lowest capillary absorption coefficient was 0.16758 mm/min½ in the SF mix. Drying shrinkage decreased with higher SF and reached a minimum value of 4000 μm/m. Heated curing reduced porosity through calcite formation and produced a dense and stable microstructure. Thermal analysis showed lower portlandite and stronger secondary hydration in SF mixes. MFA-rich mixes showed more residual portlandite, which explained their lower strength. These results confirm that MFA can be used as a sustainable SCM for producing UHPGC with good mechanical and durability performance.
{"title":"Engineering properties of municipal solid waste incineration fly ash-based thermally cured ultra-high-performance green cement composites","authors":"Nejib Ghazouani , Abdelatif Salmi , Ahmed A. Alawi Al-Naghi , Khaled Mohamed Elhadi , Ali Raza","doi":"10.1016/j.ceramint.2025.12.144","DOIUrl":"10.1016/j.ceramint.2025.12.144","url":null,"abstract":"<div><div>This study evaluates the engineering properties of ultra-high-performance green cement composites (UHPGC) made with municipal solid waste incineration fly ash (MFA). Five mix designs were prepared using a constant w/b ratio of 0.17 and 70 % Portland cement with 30 % supplementary cementitious materials. The mixes included binary systems with silica fume (SF), metakaolin (MK), or MFA and ternary blends with SF-MK or SF-MFA. All specimens were cast in 50 × 100 mm cylinders and 40 × 40 × 160 mm prisms. All mixes were thermally cured at 60 °C for 48 h. Tests included workability, density, compressive strength, modulus of elasticity, capillary water absorption, and drying shrinkage. Microstructural analysis was done using SEM/EDS, XRD, and TGA/DTG. One-way ANOVA and Tukey's HSD were used to check significance. MFA increased workability by 36.11 % because of its low intra-particle absorption. All mixes achieved compressive strengths above 100 MPa. The SF-rich mix reached 134.5 MPa at 28 days while the MFA mix reached 109.3 MPa. The ternary mixes showed balanced strength and workability with strengths of 129.2–129.9 MPa. The highest density was 2368 kg/m<sup>3</sup> in the MK mix. The lowest capillary absorption coefficient was 0.16758 mm/min½ in the SF mix. Drying shrinkage decreased with higher SF and reached a minimum value of 4000 μm/m. Heated curing reduced porosity through calcite formation and produced a dense and stable microstructure. Thermal analysis showed lower portlandite and stronger secondary hydration in SF mixes. MFA-rich mixes showed more residual portlandite, which explained their lower strength. These results confirm that MFA can be used as a sustainable SCM for producing UHPGC with good mechanical and durability performance.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 3","pages":"Pages 3532-3544"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145996516","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.11.429
Linying Xie , Xiaoxue Wang , Bingbing Yin , Hongyi Luo , Yi Yang
High-entropy zirconate ceramics (YGdErDy)2(1-x)Yb2xZr2O7 with a fluorite structure were prepared by a solid-phase reaction and high-temperature sintering, which have the potential to be applied to thermal barrier coatings (TBCs). The results show that the materials possess low thermal conductivity, high coefficient of thermal expansion, excellent mechanical properties (hardness, modulus of elasticity, and fracture toughness), and a good resistance to the corrosive properties of CMAS with corrosion depth reduced by around 85% compared to YSZ. The corrosion process and damage mechanism of CMAS are emphasized. This study focuses on a new mechanism for increasing the doping amount of Yb3+ (ions with a small radius), reducing the formation of apatite phases, and promoting the entry of RE3+ into ZrO2, which subsequently leads to the formation of a larger ZrO2 barrier layer. The selection of RE3+ with a small ionic radius is proposed as a new strategy to enhance the CMAS corrosion resistance of high-entropy rare-earth zirconate ceramics.
{"title":"Thermal/mechanical properties and CMAS corrosion resistance of (YGdErDy)2(1-x)Yb2xZr2O7 high-entropy ceramics","authors":"Linying Xie , Xiaoxue Wang , Bingbing Yin , Hongyi Luo , Yi Yang","doi":"10.1016/j.ceramint.2025.11.429","DOIUrl":"10.1016/j.ceramint.2025.11.429","url":null,"abstract":"<div><div>High-entropy zirconate ceramics (YGdErDy)<sub>2(1-x)</sub>Yb<sub>2x</sub>Zr<sub>2</sub>O<sub>7</sub> with a fluorite structure were prepared by a solid-phase reaction and high-temperature sintering, which have the potential to be applied to thermal barrier coatings (TBCs). The results show that the materials possess low thermal conductivity, high coefficient of thermal expansion, excellent mechanical properties (hardness, modulus of elasticity, and fracture toughness), and a good resistance to the corrosive properties of CMAS with corrosion depth reduced by around 85% compared to YSZ. The corrosion process and damage mechanism of CMAS are emphasized. This study focuses on a new mechanism for increasing the doping amount of Yb<sup>3+</sup> (ions with a small radius), reducing the formation of apatite phases, and promoting the entry of RE<sup>3+</sup> into ZrO<sub>2</sub>, which subsequently leads to the formation of a larger ZrO<sub>2</sub> barrier layer. The selection of RE<sup>3+</sup> with a small ionic radius is proposed as a new strategy to enhance the CMAS corrosion resistance of high-entropy rare-earth zirconate ceramics.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 1739-1752"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950085","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.11.444
Samia E. Ibrahim , Mostafa I. Abdelglil , Hany A. Abo-Mosallam
Lithium sodium silicate glasses containing MoO3 with nominal composition 30Li2O-5Na2O-YMoO3-(65-Y) SiO2 (mole %) glass (where Y = 0, 1, 3, and 5 mol. %) were successfully prepared via the melt quenching method. The influence of doping different MoO3 content on the structure, physical and mechanical strength of the prepared vitreous specimens was studied. It is determined that MoO3/SiO2 substitution led to increases in the density and molar volume and consequently weakened the glass network. It has been shown that there is a shift in the thermal parameters, such as the glass transition temperature (Tg) and crystallization temperature (Tc), towards lower temperatures for MoO3/SiO2. This attributed to the addition of MoO3 led to decreased glass formation stability and increased tendency to crystallization. The elastic modulus parameter results indicate a slight decrease in values with the replacement of silica by molybdenum due to decreased bond strength and rigidity of the glass structure. A comprehensive analysis using impedance spectroscopy, dielectric measurements, and electrical modulus formalism was conducted across a wide range of frequencies and temperatures. This study confirmed that MoO3 doping significantly enhances the electrical properties of the LNSM glass system, yielding an optimal DC conductivity of 5.51 × 10−7 S/cm and colossal permittivity (ε′> 4 × 105) in the LNSM5 sample. The material exhibits thermally activated Li+ ionic conduction with a remarkably low activation energy of 0.38 eV, following the Correlated Barrier Hopping (CBH) model. These combined features, driven by structural modification, position this glass as a highly promising candidate for solid-state electrolytes and advanced energy storage applications.
{"title":"Impact of Mo6+ on thermo-mechanical and electrical properties of sodium lithium silicate glasses as energy storage capacitors","authors":"Samia E. Ibrahim , Mostafa I. Abdelglil , Hany A. Abo-Mosallam","doi":"10.1016/j.ceramint.2025.11.444","DOIUrl":"10.1016/j.ceramint.2025.11.444","url":null,"abstract":"<div><div>Lithium sodium silicate glasses containing MoO<sub>3</sub> with nominal composition 30Li<sub>2</sub>O-5Na<sub>2</sub>O-YMoO<sub>3</sub>-(65-Y) SiO<sub>2</sub> (mole %) glass (where Y = 0, 1, 3, and 5 mol. %) were successfully prepared via the melt quenching method. The influence of doping different MoO<sub>3</sub> content on the structure, physical and mechanical strength of the prepared vitreous specimens was studied. It is determined that MoO<sub>3</sub>/SiO<sub>2</sub> substitution led to increases in the density and molar volume and consequently weakened the glass network. It has been shown that there is a shift in the thermal parameters, such as the glass transition temperature (T<sub>g</sub>) and crystallization temperature (T<sub>c</sub>), towards lower temperatures for MoO<sub>3</sub>/SiO<sub>2</sub>. This attributed to the addition of MoO<sub>3</sub> led to decreased glass formation stability and increased tendency to crystallization. The elastic modulus parameter results indicate a slight decrease in values with the replacement of silica by molybdenum due to decreased bond strength and rigidity of the glass structure. A comprehensive analysis using impedance spectroscopy, dielectric measurements, and electrical modulus formalism was conducted across a wide range of frequencies and temperatures. This study confirmed that MoO<sub>3</sub> doping significantly enhances the electrical properties of the LNSM glass system, yielding an optimal DC conductivity of 5.51 × 10<sup>−7</sup> S/cm and colossal permittivity (ε′> 4 × 10<sup>5</sup>) in the LNSM5 sample. The material exhibits thermally activated Li<sup>+</sup> ionic conduction with a remarkably low activation energy of 0.38 eV, following the Correlated Barrier Hopping (CBH) model. These combined features, driven by structural modification, position this glass as a highly promising candidate for solid-state electrolytes and advanced energy storage applications.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 1804-1817"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950095","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}
In this study, we systematically investigate the influence of potassium niobate (KNbO3) nanostructures introduced in the form of nanoparticles (NPs) and nanorods (NRs) on the magneto-resistive and flux pinning properties of YBa2Cu3O7-δ (YBCO) superconductors. Polycrystalline YBCO and YBCO–0.5 wt%KNbO3 nanocomposites are synthesized via the solid-state reaction route and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Temperature-dependent resistivity measurements under magnetic fields ranging from 0 to 7 T revealed that the incorporation of KNbO3 effectively reduced the superconducting transition width (ΔT), yielding the narrowest values of 1.46 K and 2.35 K for YBCO–KNbO3 NPs and YBCO–KNbO3 NRs, respectively at .1 T, indicating improved inter-grain connectivity. Analysis of thermally activated flux flow (TAFF) demonstrated a substantial enhancement in the activation energy (U0) for both KNbO3- added samples relative to pristine YBCO, with nanoparticles exhibiting the highest U0 values across all magnetic fields, confirming their stronger flux pinning capability. Furthermore, the upper critical field Hc2(0), estimated using Ginzburg–Landau fitting, increased from 66 T in pure YBCO to 133 T in YBCO–KNbO3 NPs and 110 T in YBCO–KNbO3 NRs, corresponding to reduced coherence lengths of 1.57 nm and 1.72 nm, respectively. Overall, these findings demonstrate that while both KNbO3 nanostructures enhance the superconducting and flux pinning performance of YBCO, nanoparticles induce more effective lattice distortions and artificial pinning centers, thereby markedly improving vortex stability and high-field superconducting behavior.
{"title":"Investigating magneto-resistivity in YBCO superconductor enhanced with potassium niobate (nanorods or nanoparticles)","authors":"Gaurav Kumar, Sandeep Kumar, Rohit Kumar , Neeraj Khare","doi":"10.1016/j.ceramint.2025.11.395","DOIUrl":"10.1016/j.ceramint.2025.11.395","url":null,"abstract":"<div><div>In this study, we systematically investigate the influence of potassium niobate (KNbO<sub>3</sub>) nanostructures introduced in the form of nanoparticles (NPs) and nanorods (NRs) on the magneto-resistive and flux pinning properties of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> (YBCO) superconductors. Polycrystalline YBCO and YBCO–0.5 wt%KNbO<sub>3</sub> nanocomposites are synthesized via the solid-state reaction route and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Temperature-dependent resistivity measurements under magnetic fields ranging from 0 to 7 T revealed that the incorporation of KNbO<sub>3</sub> effectively reduced the superconducting transition width (ΔT), yielding the narrowest values of 1.46 K and 2.35 K for YBCO–KNbO<sub>3</sub> NPs and YBCO–KNbO<sub>3</sub> NRs, respectively at .1 T, indicating improved inter-grain connectivity. Analysis of thermally activated flux flow (TAFF) demonstrated a substantial enhancement in the activation energy (U<sub>0</sub>) for both KNbO<sub>3</sub>- added samples relative to pristine YBCO, with nanoparticles exhibiting the highest U<sub>0</sub> values across all magnetic fields, confirming their stronger flux pinning capability. Furthermore, the upper critical field H<sub>c2</sub>(0), estimated using Ginzburg–Landau fitting, increased from 66 T in pure YBCO to 133 T in YBCO–KNbO<sub>3</sub> NPs and 110 T in YBCO–KNbO<sub>3</sub> NRs, corresponding to reduced coherence lengths of 1.57 nm and 1.72 nm, respectively. Overall, these findings demonstrate that while both KNbO<sub>3</sub> nanostructures enhance the superconducting and flux pinning performance of YBCO, nanoparticles induce more effective lattice distortions and artificial pinning centers, thereby markedly improving vortex stability and high-field superconducting behavior.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 1646-1654"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950232","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.12.037
G.C.V. Prasad , Nipa Roy , T.Ranjeth Kumar Reddy
In this study, cerium (Ce)-doped octahedral ZnMn2O4 microcrystallites were synthesized through solution combustion and tested as battery-type electrodes for hybrid supercapacitor applications. Three samples with different Ce contents—undoped, 0.5 %Ce-ZnMn2O4, and 1 %Ce-ZnMn2O4—were prepared to assess the effects of doping levels. The materials' structural, morphological, and surface properties were extensively characterized using various analytical techniques. The 1 %Ce-doped ZnMn2O4 exhibited significant improvements in structure and surface features, including a smaller crystallite size, a well-defined octahedral shape, and a high specific surface area of 42.71 m2/g compared to the other samples. These features facilitate better ion and electron transport and provide more electroactive sites. Electrochemical testing confirmed the battery-like behavior of all electrodes, with 1 %Ce-ZnMn2O4 achieving a high specific capacity of 426.1 C g−1 at 1 A g−1, greatly surpassing the capacity of the undoped (145.5 C g−1) and 0.5 % Ce-ZnMn2O4 (401 C g−1) electrodes. Even at 20 A g−1, the 1 % Ce-ZnMn2O4 electrode retained 60 % of its initial capacity and maintained 85 % stability after 5000 cycles. These findings demonstrate that doping effectively enhances the performance of ZnMn2O4-based battery-type electrodes for next-generation hybrid supercapacitors.
在本研究中，通过溶液燃烧合成了掺杂铈（Ce）的八面体ZnMn2O4微晶，并测试了其作为混合超级电容器电池型电极的应用。制备了三种不同Ce含量的样品——未掺杂、0.5% Ce- znmn2o4和1% Ce- znmn2o4，以评估掺杂水平的影响。使用各种分析技术对材料的结构、形态和表面性能进行了广泛的表征。与其他样品相比，掺1% ce的ZnMn2O4在结构和表面特征上有了显著的改善，包括更小的晶粒尺寸、清晰的八面体形状和高达42.71 m2/g的比表面积。这些特征有助于更好的离子和电子传输，并提供更多的电活性位点。电化学测试证实了所有电极的电池样性能，其中1% Ce-ZnMn2O4在1 a g−1时获得了426.1 C g−1的高比容量，大大超过了未掺杂（145.5 C g−1）和0.5% Ce-ZnMn2O4 （401 C g−1）电极的容量。即使在20a g−1下，1% Ce-ZnMn2O4电极在5000次循环后仍保持60%的初始容量和85%的稳定性。这些发现表明，掺杂有效地提高了znmn2o4基电池型电极用于下一代混合超级电容器的性能。
{"title":"Ce doping-induced structural and electrochemical performance enhancement in octahedral ZnMn2O4 microcrystallites for hybrid supercapacitor applications","authors":"G.C.V. Prasad , Nipa Roy , T.Ranjeth Kumar Reddy","doi":"10.1016/j.ceramint.2025.12.037","DOIUrl":"10.1016/j.ceramint.2025.12.037","url":null,"abstract":"<div><div>In this study, cerium (Ce)-doped octahedral ZnMn<sub>2</sub>O<sub>4</sub> microcrystallites were synthesized through solution combustion and tested as battery-type electrodes for hybrid supercapacitor applications. Three samples with different Ce contents—undoped, 0.5 %Ce-ZnMn<sub>2</sub>O<sub>4</sub>, and 1 %Ce-ZnMn<sub>2</sub>O<sub>4</sub>—were prepared to assess the effects of doping levels. The materials' structural, morphological, and surface properties were extensively characterized using various analytical techniques. The 1 %Ce-doped ZnMn<sub>2</sub>O<sub>4</sub> exhibited significant improvements in structure and surface features, including a smaller crystallite size, a well-defined octahedral shape, and a high specific surface area of 42.71 m<sup>2</sup>/g compared to the other samples. These features facilitate better ion and electron transport and provide more electroactive sites. Electrochemical testing confirmed the battery-like behavior of all electrodes, with 1 %Ce-ZnMn<sub>2</sub>O<sub>4</sub> achieving a high specific capacity of 426.1 C g<sup>−1</sup> at 1 A g<sup>−1</sup>, greatly surpassing the capacity of the undoped (145.5 C g<sup>−1</sup>) and 0.5 % Ce-ZnMn<sub>2</sub>O<sub>4</sub> (401 C g<sup>−1</sup>) electrodes. Even at 20 A g<sup>−1</sup>, the 1 % Ce-ZnMn<sub>2</sub>O<sub>4</sub> electrode retained 60 % of its initial capacity and maintained 85 % stability after 5000 cycles. These findings demonstrate that doping effectively enhances the performance of ZnMn<sub>2</sub>O<sub>4</sub>-based battery-type electrodes for next-generation hybrid supercapacitors.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 2147-2159"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950237","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.12.041
Carlos Fernandes Mariano Nogueira , Paulo Henrique Oliveira Junior , Euler Araujo dos Santos
Stabilizing iron within the hydroxyapatite (HA) lattice remains a challenge, limiting the development of iron-containing calcium phosphates for biomedical and technological applications. Evidence suggests that carbonate (CO32−), along with other substituents and lattice defects, plays a critical role in iron stabilization and phase transformation control. In this study, we investigated the effects of CO32− and HPO42− on iron capture and stabilization in HA, as well as their influence on structural transformations at elevated temperatures. HA was synthesized via an acid-base reaction between phosphoric acid and calcium hydroxide, carried out in the presence of Fe at four different concentrations. A portion of the samples was calcined at 1000 °C to evaluate thermal stability. The resulting materials were characterized using wavelength-dispersive X-ray fluorescence (WDXRF), X-ray diffraction (XRD) data, scanning electron miscroscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy. Our results showed that increasing Fe content progressively reduced HA crystallinity and inhibited CO32− incorporation from the aqueous medium during synthesis. HPO42− incorporation was likewise impeded. Notably, variations in lattice parameters were more strongly correlated with CO32− content than with Fe concentration. Iron insertion disrupted the phosphate environment and depleted hydroxyl groups, suggesting Fe occupation within hydroxyl channels. Upon calcination at 1000 °C, Fe-containing HA underwent phase transformation, accompanied by complete loss of CO32− and HPO42− and the formation of iron oxides and β-tricalcium phosphate (β-TCP). Approximately half of the initial Fe segregated as iron oxide, while the remainder was retained in residual HA and/or β-TCP phases. Magnetite formed at 6.0 mol % Fe, whereas hematite predominated at higher concentrations. The presence of CO32− appeared to facilitate magnetite formation by providing a reducing environment that promotes Fe3+ to Fe2+ conversion during thermal decomposition.
{"title":"Effect of ionic substituents on iron stabilization into hydroxyapatite: a study by Rietveld and FTIR","authors":"Carlos Fernandes Mariano Nogueira , Paulo Henrique Oliveira Junior , Euler Araujo dos Santos","doi":"10.1016/j.ceramint.2025.12.041","DOIUrl":"10.1016/j.ceramint.2025.12.041","url":null,"abstract":"<div><div>Stabilizing iron within the hydroxyapatite (HA) lattice remains a challenge, limiting the development of iron-containing calcium phosphates for biomedical and technological applications. Evidence suggests that carbonate (CO<sub>3</sub><sup>2−</sup>), along with other substituents and lattice defects, plays a critical role in iron stabilization and phase transformation control. In this study, we investigated the effects of CO<sub>3</sub><sup>2−</sup> and HPO<sub>4</sub><sup>2−</sup> on iron capture and stabilization in HA, as well as their influence on structural transformations at elevated temperatures. HA was synthesized via an acid-base reaction between phosphoric acid and calcium hydroxide, carried out in the presence of Fe at four different concentrations. A portion of the samples was calcined at 1000 °C to evaluate thermal stability. The resulting materials were characterized using wavelength-dispersive X-ray fluorescence (WDXRF), X-ray diffraction (XRD) data, scanning electron miscroscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy. Our results showed that increasing Fe content progressively reduced HA crystallinity and inhibited CO<sub>3</sub><sup>2−</sup> incorporation from the aqueous medium during synthesis. HPO<sub>4</sub><sup>2−</sup> incorporation was likewise impeded. Notably, variations in lattice parameters were more strongly correlated with CO<sub>3</sub><sup>2−</sup> content than with Fe concentration. Iron insertion disrupted the phosphate environment and depleted hydroxyl groups, suggesting Fe occupation within hydroxyl channels. Upon calcination at 1000 °C, Fe-containing HA underwent phase transformation, accompanied by complete loss of CO<sub>3</sub><sup>2−</sup> and HPO<sub>4</sub><sup>2−</sup> and the formation of iron oxides and β-tricalcium phosphate (β-TCP). Approximately half of the initial Fe segregated as iron oxide, while the remainder was retained in residual HA and/or β-TCP phases. Magnetite formed at 6.0 mol % Fe, whereas hematite predominated at higher concentrations. The presence of CO<sub>3</sub><sup>2−</sup> appeared to facilitate magnetite formation by providing a reducing environment that promotes Fe<sup>3+</sup> to Fe<sup>2+</sup> conversion during thermal decomposition.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 2196-2207"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950241","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.11.447
Nian Luo , Bin Yang , Zihao Zheng, Kaiyan Guo, Miao He, Jinming Guo, Xunzhong Shang
Relaxor ceramics have the advantages of high energy storage efficiency and excellent stability, which have received more and more attention in recently. However, a major challenge of them is to enhance the energy storage density and meet the new applications that require miniaturization and integration of pulsed power systems. In this paper, the conventional solid-state sintering technique was used to prepare the Bi0.5Na0.5TiO3 (BNT)-based lead-free relaxor ceramic via adjusting multi-component at A-site for energy storage applications. A large recoverable energy storage density (Wrec∼5.18 J/cm3) and a high energy storage efficiency (η∼85.72 %) was obtained in the BNT-based ceramics at 380 kV/cm. High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) was adopted to explore the structural characterizations of the fabricated relaxor ferroelectric ceramics. Furthermore, both Wrec and η also showed high stabilities in the temperature range of 20–120 °C and superb fatigue resistances with 20000 cycles. This study provides a new idea for developing BNT-based lead-free perovskite dielectrics and proposes an innovative approach for designing environment friendly high-performance dielectric capacitors for future energy storage applications.
{"title":"Energy storage performance in BNT-based lead-free relaxor ceramics with composition optimization","authors":"Nian Luo , Bin Yang , Zihao Zheng, Kaiyan Guo, Miao He, Jinming Guo, Xunzhong Shang","doi":"10.1016/j.ceramint.2025.11.447","DOIUrl":"10.1016/j.ceramint.2025.11.447","url":null,"abstract":"<div><div>Relaxor ceramics have the advantages of high energy storage efficiency and excellent stability, which have received more and more attention in recently. However, a major challenge of them is to enhance the energy storage density and meet the new applications that require miniaturization and integration of pulsed power systems. In this paper, the conventional solid-state sintering technique was used to prepare the Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> (BNT)-based lead-free relaxor ceramic via adjusting multi-component at A-site for energy storage applications. A large recoverable energy storage density (<em>W</em><sub>rec</sub>∼5.18 J/cm<sup>3</sup>) and a high energy storage efficiency (<em>η</em>∼85.72 %) was obtained in the BNT-based ceramics at 380 kV/cm. High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) was adopted to explore the structural characterizations of the fabricated relaxor ferroelectric ceramics. Furthermore, both <em>W</em><sub>rec</sub> and <em>η</em> also showed high stabilities in the temperature range of 20–120 °C and superb fatigue resistances with 20000 cycles. This study provides a new idea for developing BNT-based lead-free perovskite dielectrics and proposes an innovative approach for designing environment friendly high-performance dielectric capacitors for future energy storage applications.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 2208-2213"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950285","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.12.032
Mei Li , Zhicheng Li , Yilin Xu , Tianren Ouyang , Hong Zhang
Low-temperature sintering (LTS) of thermistor ceramics can reduce energy consumption and expand the range of product categories of the thermistor materials, e.g., chip components, multi-layer sensitive components and integrated devices, etc., besides the traditional ceramic products. Here, BiPO4 is selected as sintering aids and performance modifier for LiF-doped NiO based ceramics for the negative temperature coefficient (NTC) thermistors. Dense NiO-based ceramics can be obtained by being sintered at the sintering temperatures of 940 °C–1140 °C with various contents of BiPO4 as sintering aids. While the LiF-doped NiO ceramics without BiPO4 require a sintering temperature of 1250 °C. By altering the contents of BiPO4, the LiF-doped NiO ceramics exhibit typical NTC characteristics with adjustable room-temperature resistivities ranging from 54.2 Ω cm to 11.86 kΩ cm and the NTC thermal-sensitivity constants ranging from 1872 K to 4404 K. Based on the analyses of phase composition, microstructures, valence states of elements and complex impedance spectroscopies, the sinter-ability and electronic properties of the LiF-doped NiO ceramics modified with BiPO4 are investigated.
{"title":"BiPO4 modified LiF-doped NiO ceramics for NTC thermistor applications","authors":"Mei Li , Zhicheng Li , Yilin Xu , Tianren Ouyang , Hong Zhang","doi":"10.1016/j.ceramint.2025.12.032","DOIUrl":"10.1016/j.ceramint.2025.12.032","url":null,"abstract":"<div><div>Low-temperature sintering (LTS) of thermistor ceramics can reduce energy consumption and expand the range of product categories of the thermistor materials, <em>e.g.,</em> chip components, multi-layer sensitive components and integrated devices, <em>etc</em>., besides the traditional ceramic products. Here, BiPO<sub>4</sub> is selected as sintering aids and performance modifier for LiF-doped NiO based ceramics for the negative temperature coefficient (NTC) thermistors. Dense NiO-based ceramics can be obtained by being sintered at the sintering temperatures of 940 °C–1140 °C with various contents of BiPO<sub>4</sub> as sintering aids. While the LiF-doped NiO ceramics without BiPO<sub>4</sub> require a sintering temperature of 1250 °C. By altering the contents of BiPO<sub>4</sub>, the LiF-doped NiO ceramics exhibit typical NTC characteristics with adjustable room-temperature resistivities ranging from 54.2 Ω cm to 11.86 kΩ cm and the NTC thermal-sensitivity constants ranging from 1872 K to 4404 K. Based on the analyses of phase composition, microstructures, valence states of elements and complex impedance spectroscopies, the sinter-ability and electronic properties of the LiF-doped NiO ceramics modified with BiPO<sub>4</sub> are investigated.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 2094-2105"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950294","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 : 2026-01-01DOI: 10.1016/j.ceramint.2025.11.308
Lei Wang , Shuaishuai Li , Zelin Zhang , Yuyao Guo , Jianhua Cao , Xuhui Xia
<div><div>Electrical erosion at the shaft-end bearings of electric-vehicle motors is drawing growing concern and needs urgent remedy. At present, research on Al<sub>2</sub>O<sub>3</sub>-based, multi-dopant-modified ceramic insulating coatings remains largely unexplored. Accordingly, five Al<sub>2</sub>O<sub>3</sub>-based ceramic insulating coatings with different TiO<sub>2</sub>, Y<sub>2</sub>O<sub>3</sub>, and Cr<sub>2</sub>O<sub>3</sub> doping ratios were fabricated by atmospheric plasma spraying (APS). The coatings’ microstructure, phase composition, electrical insulation properties, and mechanical properties were investigated. This study aimed to fabricate multi-dopant-modified ceramic coatings. Commercial Al<sub>2</sub>O<sub>3</sub> and Al<sub>2</sub>O<sub>3</sub>–3 %TiO<sub>2</sub> (AT3) powders were selected. Composite powders of AT3–10 %Y<sub>2</sub>O<sub>3</sub>, AT3–10 %Cr<sub>2</sub>O<sub>3</sub>, and AT3–5 %Y<sub>2</sub>O<sub>3</sub>–5 %Cr<sub>2</sub>O<sub>3</sub> were prepared in-house. Grayscale image analysis was applied to coating cross-sections to process the morphology and to calculate the defect area fraction, including porosity. For phase and structural analysis, XRD data were analyzed by Rietveld refinement (whole-pattern fitting), and electron backscatter diffraction (EBSD) was used for phase identification and grain-boundary characterization of the ceramic layer. The electrical properties (insulation resistance, volume resistivity, breakdown voltage, dielectric strength, dielectric constant, and dielectric loss), mechanical properties (adhesion strength and hardness), and surface roughness of the coatings were systematically characterized. The experimental results showed that the AT3–5 %Y<sub>2</sub>O<sub>3</sub>–5 %Cr<sub>2</sub>O<sub>3</sub> coating exhibited the best overall performance.Compared with the pure Al<sub>2</sub>O<sub>3</sub> coating, its defect ratio (including porosity) decreased by 78.7 %, the α-Al<sub>2</sub>O<sub>3</sub> phase content increased by 1.82–2.33 times, the breakdown voltage improved by 4 %, and the bonding strength increased by 23.6 %. In addition, the hardness and volume resistivity of this coating reached 98 % and 84 % of those of the pure Al<sub>2</sub>O<sub>3</sub> coating, respectively. These improvements were mainly attributed to synergistic effects among multiple constituents. Owing to its low melting point, TiO<sub>2</sub> effectively filled pores within the coating. The addition of Y<sub>2</sub>O<sub>3</sub> refined the microstructure and suppressed the formation of microcracks. The presence of unmelted or semi-molten Al<sub>2</sub>O<sub>3</sub>, Y<sub>2</sub>O<sub>3</sub>, and Cr<sub>2</sub>O<sub>3</sub> particles jointly enhanced the overall hardness. These factors also collectively promoted the formation of the α-Al<sub>2</sub>O<sub>3</sub> (corundum) phase.An adverse effect of TiO<sub>2</sub> was also observed in this study. Incorporating TiO<sub>2</sub> significantly reduced the
{"title":"Enhancing the α-phase content and comprehensive performance of plasma sprayed Al2O3-based insulating coatings through Y2O3-Cr2O3-TiO2 multi-component modification","authors":"Lei Wang , Shuaishuai Li , Zelin Zhang , Yuyao Guo , Jianhua Cao , Xuhui Xia","doi":"10.1016/j.ceramint.2025.11.308","DOIUrl":"10.1016/j.ceramint.2025.11.308","url":null,"abstract":"<div><div>Electrical erosion at the shaft-end bearings of electric-vehicle motors is drawing growing concern and needs urgent remedy. At present, research on Al<sub>2</sub>O<sub>3</sub>-based, multi-dopant-modified ceramic insulating coatings remains largely unexplored. Accordingly, five Al<sub>2</sub>O<sub>3</sub>-based ceramic insulating coatings with different TiO<sub>2</sub>, Y<sub>2</sub>O<sub>3</sub>, and Cr<sub>2</sub>O<sub>3</sub> doping ratios were fabricated by atmospheric plasma spraying (APS). The coatings’ microstructure, phase composition, electrical insulation properties, and mechanical properties were investigated. This study aimed to fabricate multi-dopant-modified ceramic coatings. Commercial Al<sub>2</sub>O<sub>3</sub> and Al<sub>2</sub>O<sub>3</sub>–3 %TiO<sub>2</sub> (AT3) powders were selected. Composite powders of AT3–10 %Y<sub>2</sub>O<sub>3</sub>, AT3–10 %Cr<sub>2</sub>O<sub>3</sub>, and AT3–5 %Y<sub>2</sub>O<sub>3</sub>–5 %Cr<sub>2</sub>O<sub>3</sub> were prepared in-house. Grayscale image analysis was applied to coating cross-sections to process the morphology and to calculate the defect area fraction, including porosity. For phase and structural analysis, XRD data were analyzed by Rietveld refinement (whole-pattern fitting), and electron backscatter diffraction (EBSD) was used for phase identification and grain-boundary characterization of the ceramic layer. The electrical properties (insulation resistance, volume resistivity, breakdown voltage, dielectric strength, dielectric constant, and dielectric loss), mechanical properties (adhesion strength and hardness), and surface roughness of the coatings were systematically characterized. The experimental results showed that the AT3–5 %Y<sub>2</sub>O<sub>3</sub>–5 %Cr<sub>2</sub>O<sub>3</sub> coating exhibited the best overall performance.Compared with the pure Al<sub>2</sub>O<sub>3</sub> coating, its defect ratio (including porosity) decreased by 78.7 %, the α-Al<sub>2</sub>O<sub>3</sub> phase content increased by 1.82–2.33 times, the breakdown voltage improved by 4 %, and the bonding strength increased by 23.6 %. In addition, the hardness and volume resistivity of this coating reached 98 % and 84 % of those of the pure Al<sub>2</sub>O<sub>3</sub> coating, respectively. These improvements were mainly attributed to synergistic effects among multiple constituents. Owing to its low melting point, TiO<sub>2</sub> effectively filled pores within the coating. The addition of Y<sub>2</sub>O<sub>3</sub> refined the microstructure and suppressed the formation of microcracks. The presence of unmelted or semi-molten Al<sub>2</sub>O<sub>3</sub>, Y<sub>2</sub>O<sub>3</sub>, and Cr<sub>2</sub>O<sub>3</sub> particles jointly enhanced the overall hardness. These factors also collectively promoted the formation of the α-Al<sub>2</sub>O<sub>3</sub> (corundum) phase.An adverse effect of TiO<sub>2</sub> was also observed in this study. Incorporating TiO<sub>2</sub> significantly reduced the ","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 1530-1551"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950383","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}
To improve the quality of white LED and develop plant growth lighting, considerable efforts have been devoted to investigating red phosphor. Eu3+-activated phosphors are well-known red-emitting components due to their 5D0-7F1,2 transitions in various applications. It is also found that its 5D0-7F4 transition in the range of far-red wavelengths has potential applications in the fields of daily and agricultural lighting. In this study, two kinds of Eu3+-doped layered perovskite La2Ti2O7 and A2La2Ti3O10 (A = Li, Na, K) phosphors were synthesized by the solid-state method. The crystal structure, absorption, excitation, and emission spectra of all the samples were investigated in detail. Dissimilar luminescent behaviors of the studied samples were observed. Due to the different crystal structure and chemical composition of the host matrix, each compound exhibits a different emission spectrum. Specifically, Eu3+ occupies a lower symmetric La3+ site in A2La2Ti3O10 (A = Li, Na, K) phosphors, resulting in an intense 5D0-7F4 far-red emission, while in La2Ti2O7:Eu3+, Eu3+ gives a weak 5D0-7F4 emission. To the best of our knowledge, this is the first report that Eu3+ exhibits a strong 5D0-7F4 far-red emission in the titanate host lattices with perovskite structure. Besides, A2La2Ti3O10:Eu3+ (A = Li, Na, K) phosphors achieve higher photoluminescence efficiency than La2Ti2O7:Eu3+. Among them, the internal quantum efficiency of the optimized Li2La2Ti3O10:1.2Eu3+ is about 84.7 %, and it has a better thermal stability (80 % at 125 °C). Furthermore, good photoelectric performances of red/white-LEDs fabricated by utilizing the representative Li2La2Ti3O10:1.2Eu3+ as red/far-red components indicate that it has potential applications in indoor/outdoor lighting and plant growth lighting. This study provides a feasible way for developing efficient Eu3+-activated far-red optical materials.
{"title":"On the photoluminescence differences of Eu3+-activated layered perovskite La2Ti2O7 and A2La2Ti3O10 (A = Li, Na, K) phosphors for potential applications in white LEDs and plant growth lighting","authors":"Dong Yi, Jiawei Fu, Fenzhong Long, Jin Han, Fangui Meng, Xinmin Zhang","doi":"10.1016/j.ceramint.2025.11.421","DOIUrl":"10.1016/j.ceramint.2025.11.421","url":null,"abstract":"<div><div>To improve the quality of white LED and develop plant growth lighting, considerable efforts have been devoted to investigating red phosphor. Eu<sup>3+</sup>-activated phosphors are well-known red-emitting components due to their <sup>5</sup>D<sub>0</sub>-<sup>7</sup>F<sub>1,2</sub> transitions in various applications. It is also found that its <sup>5</sup>D<sub>0</sub>-<sup>7</sup>F<sub>4</sub> transition in the range of far-red wavelengths has potential applications in the fields of daily and agricultural lighting. In this study, two kinds of Eu<sup>3+</sup>-doped layered perovskite La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> and A<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub> (A = Li, Na, K) phosphors were synthesized by the solid-state method. The crystal structure, absorption, excitation, and emission spectra of all the samples were investigated in detail. Dissimilar luminescent behaviors of the studied samples were observed. Due to the different crystal structure and chemical composition of the host matrix, each compound exhibits a different emission spectrum. Specifically, Eu<sup>3+</sup> occupies a lower symmetric La<sup>3+</sup> site in A<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub> (A = Li, Na, K) phosphors, resulting in an intense <sup>5</sup>D<sub>0</sub>-<sup>7</sup>F<sub>4</sub> far-red emission, while in La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>:Eu<sup>3+</sup>, Eu<sup>3+</sup> gives a weak <sup>5</sup>D<sub>0</sub>-<sup>7</sup>F<sub>4</sub> emission. To the best of our knowledge, this is the first report that Eu<sup>3+</sup> exhibits a strong <sup>5</sup>D<sub>0</sub>-<sup>7</sup>F<sub>4</sub> far-red emission in the titanate host lattices with perovskite structure. Besides, A<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub>:Eu<sup>3+</sup> (A = Li, Na, K) phosphors achieve higher photoluminescence efficiency than La<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>:Eu<sup>3+</sup>. Among them, the internal quantum efficiency of the optimized Li<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub>:1.2Eu<sup>3+</sup> is about 84.7 %, and it has a better thermal stability (80 % at 125 °C). Furthermore, good photoelectric performances of red/white-LEDs fabricated by utilizing the representative Li<sub>2</sub>La<sub>2</sub>Ti<sub>3</sub>O<sub>10</sub>:1.2Eu<sup>3+</sup> as red/far-red components indicate that it has potential applications in indoor/outdoor lighting and plant growth lighting. This study provides a feasible way for developing efficient Eu<sup>3+</sup>-activated far-red optical materials.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"52 2","pages":"Pages 1705-1714"},"PeriodicalIF":5.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950083","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}
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