Ceramics

21 pages, 8972 KB

Open AccessArticle

Mechanism and Optimization of Metakaolin-Based Geopolymer Grout Under High Water-to-Solid Ratio: Steel Slag as a Calcareous Source

by Lijuan He, Yuhang Huang, Jianhua Zhou, Yi Wang, Jingwei Yang, Xuan Liu, Shuping Wang and Zhigang Zhang

Ceramics 2026, 9(1), 9; https://doi.org/10.3390/ceramics9010009 - 21 Jan 2026

Cited by 1 | Viewed by 737

Abstract

This study systematically examines the fluidity, setting time, mechanical properties, and microstructural evolution of metakaolin-based geopolymer grouting materials with a relatively high water-to-solid (W/S) ratio window. A four-factor, three-level orthogonal experimental design was employed to identify the dominant factors and main effect trends [...] Read more.

This study systematically examines the fluidity, setting time, mechanical properties, and microstructural evolution of metakaolin-based geopolymer grouting materials with a relatively high water-to-solid (W/S) ratio window. A four-factor, three-level orthogonal experimental design was employed to identify the dominant factors and main effect trends of W/S ratio, alkali dosage, water glass modulus (Ms, molar ratio of SiO₂ to Na₂O in alkali solution), and steel slag content on the material’s performance. The results indicated that the W/S ratio predominantly governed fluidity, while the alkali content was the primary controlling factor for setting time and early-age strength. An intermediate range of water glass modulus with a value of 1.6 provided balanced performance. The incorporation of steel slag with a range of 10–20% showed an age-dependent contribution: it not only tended to improve the rheology of the paste but also the later-age strength. XRD, FTIR, and SEM/EDS results suggested that the hardened binders were dominated by amorphous products, where alumimosilicate gel (N-A-S-H) and Ca-containing gel (C-S-H/C-A-S-H) may coexist depending on calcium availability and activator chemistry. The proposed parameter ranges are valid within the studied design space and provide guidance for the mix design of high-W/S geopolymer grout. Full article

(This article belongs to the Special Issue The Production Processes and Applications of Geopolymers, 2nd Edition)

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18 pages, 4345 KB

Open AccessArticle

The Influence of Different Zirconium Oxide Processing Variants on Selected Parameters of Roughness, Surface Wettability, and Phase Transformations

by Beata Śmielak, Leszek Klimek, Marco Ferrari and Kamil Krześniak

Ceramics 2026, 9(1), 10; https://doi.org/10.3390/ceramics9010010 - 21 Jan 2026

Cited by 1 | Viewed by 842

Abstract

How does zirconia processing affect the degree of tetragonal to monoclinic phase transformation (t ⟶ m) and the development and wettability of the surface? One hundred and twenty-four samples made of sintered zirconium were divided into four groups based on the following treatments: [...] Read more.

How does zirconia processing affect the degree of tetragonal to monoclinic phase transformation (t ⟶ m) and the development and wettability of the surface? One hundred and twenty-four samples made of sintered zirconium were divided into four groups based on the following treatments: grinding, polishing, sandblasting with Al₂O₃, or sandblasting with SiC. After surface treatment, the samples were subjected to the following tests: X-ray diffraction, microscopic examination, surface roughness measurements, and surface wettability. The highest values are achieved after the grinding process (R_a = 0.63; R_z = 9.29; R_q = 1.28), and the lowest values are found after polishing (R_a = 0.11; R_z = 0.71; R_q = 0.36). All samples, apart from those sandblasted with Al₂O₃ (Θ = 121.59°), showed wettability with the polar liquid. The best wettability was noted for sandblasted SiC samples (Θ = 41.22°) and the lowest was noted for polished samples (Θ = 80.61°). All samples showed wettability with an apolar liquid (Θ < 90°). A significant transformation (t ⟶ m) was noted in all tested samples: about 14% for ground, 17% for polished, 13.8% for Al₂O₃ sandblasting, and 13.1% for SiC sandblasting samples. The type of processing method has a significant impact on the selected parameters of roughness, surface wettability, and phase transformations. Full article

(This article belongs to the Special Issue Advances in Ceramics, 3rd Edition)

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11 pages, 812 KB

Open AccessSystematic Review

Mastoid Obliteration Using Bioceramic Scaffold After Canal Wall Down Mastoidectomy: A Systematic Review

by Kyung Hoon Sun, Cheol Hee Choi and Chul Ho Jang

Ceramics 2026, 9(1), 8; https://doi.org/10.3390/ceramics9010008 - 15 Jan 2026

Cited by 1 | Viewed by 1480

Abstract

Canal wall down mastoidectomy (CWD) effectively eradicates cholesteatoma and chronic otitis media but frequently results in a problematic open mastoid cavity. Mastoid obliteration aims to reduce cavity-related morbidity. Bioceramic materials, including hydroxyapatite (HA), tricalcium phosphate (TCP), and bioactive glass (BAG), have been increasingly [...] Read more.

Canal wall down mastoidectomy (CWD) effectively eradicates cholesteatoma and chronic otitis media but frequently results in a problematic open mastoid cavity. Mastoid obliteration aims to reduce cavity-related morbidity. Bioceramic materials, including hydroxyapatite (HA), tricalcium phosphate (TCP), and bioactive glass (BAG), have been increasingly adopted because of their osteoconductive, biocompatible, and antimicrobial properties. This systematic review evaluates the clinical outcomes and complications of bioceramic mastoid obliteration following CWD. A systematic literature search of PubMed, Scopus, and Web of Science was conducted for studies published between 2005 and 2025, following PRISMA guidelines. Clinical studies reporting outcomes of bioceramic mastoid obliteration after CWD were included. Thirteen clinical studies were included. HA-, TCP-, and BAG-based materials demonstrated high obliteration success rates (>90% in most series). BAG S53P4 was consistently associated with low infection rates and favorable epithelialization, whereas earlier HA cement formulations were occasionally associated with revision-requiring complications. Bioceramic scaffolds represent safe and effective materials for mastoid obliteration after CWD. BAG offers additional antibacterial advantages, while HA provides predictable volume stability. Further prospective and comparative studies are required to establish material superiority and long-term outcomes. Full article

(This article belongs to the Special Issue Ceramics Containing Active Molecules for Biomedical Applications)

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15 pages, 3324 KB

Open AccessArticle

Tuning Oxygen Reduction Kinetics in LaSrCoO₄ with Strained Epitaxial Thin Films and Wrinkled Freestanding Membranes

by Habib Rostaghi Chalaki, Ebenezer Seesi, Mohammad El Loubani and Dongkyu Lee

Ceramics 2026, 9(1), 7; https://doi.org/10.3390/ceramics9010007 - 14 Jan 2026

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Abstract

Sluggish oxygen reduction reaction (ORR) remains a critical barrier to advancing intermediate-temperature electrochemical energy devices. Here, we demonstrate that strain engineering in two platforms, epitaxial thin films and freestanding membranes, systematically tunes ORR kinetics in Ruddlesden-Popper LaSrCoO₄. In epitaxial films, film [...] Read more.

Sluggish oxygen reduction reaction (ORR) remains a critical barrier to advancing intermediate-temperature electrochemical energy devices. Here, we demonstrate that strain engineering in two platforms, epitaxial thin films and freestanding membranes, systematically tunes ORR kinetics in Ruddlesden-Popper LaSrCoO₄. In epitaxial films, film thickness is varied to control in-plane tensile strain, whereas in freestanding membranes strain relaxation during the release step using water-soluble sacrificial layers produces flat or wrinkled architectures. Electrochemical impedance spectroscopy analysis reveals more than an order of magnitude increase in the oxygen surface exchange coefficient for tensile-strained films relative to relaxed films, together with a larger oxygen vacancy concentration. Wrinkled freestanding membranes provide a further increase in oxygen surface exchange kinetics and a lower activation energy, which are attributed to increased active surface area and local strain variation. These results identify epitaxial tensile strain and controlled wrinkling as practical design parameters for optimizing ORR activity in Ruddlesden-Popper oxides. Full article

(This article belongs to the Special Issue Nanoceramics and Two-Dimensional Ceramic Materials)

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12 pages, 569 KB

Open AccessArticle

Sustainable Production of Mullite Grogs from Industrial By-Products

by Josef Škvarka, Iva Janáková, František Pticen and Radmila Kučerová

Ceramics 2026, 9(1), 6; https://doi.org/10.3390/ceramics9010006 - 12 Jan 2026

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Abstract

This study focuses on preparing mullite grogs derived from selected waste materials and kaolin treated with advanced technologies to achieve high thermal resistance and low thermal expansion. The investigated waste materials include dust removal RON, slurry DE, feldspar dust removal from Halamky, and [...] Read more.

This study focuses on preparing mullite grogs derived from selected waste materials and kaolin treated with advanced technologies to achieve high thermal resistance and low thermal expansion. The investigated waste materials include dust removal RON, slurry DE, feldspar dust removal from Halamky, and waste generated during the feldspar grinding at the Halamky I deposit. These materials (Red kaolin from Vidnava, Slurry DE, Dust-off RON, Feldspar dust-off Halamky) were processed into grogs and subsequently applied for the production of high-mullite ceramics. The influence of cristobalite admixture was also assessed. The chemical composition was determined by X-ray fluorescence (XRF), while the phase composition was analysed by X-ray diffraction (XRD). Amorphous mullite grogs with mullite contents greater than 40% were successfully prepared. Despite the relatively high iron content, the resulting products exhibited the desired white colour after firing and demonstrated properties that make them promising candidates for advanced refractory applications. The study highlights the potential to valorise industrial waste materials for high-value ceramic applications. Full article

(This article belongs to the Special Issue Advances in Ceramics, 3rd Edition)

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14 pages, 1098 KB

Open AccessArticle

The Effect of Ni Doping on the Mechanical and Thermal Properties of Spinel-Type LiMn₂O₄: A Theoretical Study

by Xiaoran Li, Lu Ren, Changxin Li, Lili Zhang, Jincheng Ji, Mao Peng and Pengyu Xu

Ceramics 2026, 9(1), 5; https://doi.org/10.3390/ceramics9010005 - 10 Jan 2026

Cited by 1 | Viewed by 871

Abstract

The development of lithium-ion batteries necessitates cathode materials that possess excellent mechanical and thermal properties in addition to electrochemical performance. As a prominent functional ceramic, the properties of spinel LiMn₂O₄ are governed by its atomic-level structure. This study systematically investigates [...] Read more.

The development of lithium-ion batteries necessitates cathode materials that possess excellent mechanical and thermal properties in addition to electrochemical performance. As a prominent functional ceramic, the properties of spinel LiMn₂O₄ are governed by its atomic-level structure. This study systematically investigates the impact of Ni doping concentration on the mechanical and thermal properties of spinel LiNi_xMn_2−xO₄ via first-principles calculations combined with the bond valence model. The results suggest that when x = 0.25, the LiNi_xMn_2−xO₄ shows excellent mechanical properties, including a high bulk modulus and hardness, due to the favorable ratio of bond valence to bonds length in octahedra. Furthermore, this optimized composition shows a lower thermal expansion coefficient. Additionally, Ni doping concentration has a very minimal influence on the maximum tolerable temperature of the cathode material during rapid heating. Therefore, from the perspective of mechanical and thermal properties, this composition could be beneficial for improving the cycling life of the battery, since comparatively inferior mechanical properties and a higher thermal expansion coefficient make it prone to microcrack formation during charge–discharge cycles. Full article

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12 pages, 4598 KB

Open AccessArticle

Nanosized Synthetic Smectic Clay-Based Hydrogel with Controlled Release of Oxygen for Applications in Skin Wounds

by Almiro Mendes Costa Neto, Caterine Yesenia Carrasco Montesdeoca, Bruno Pereira da Silva Neto, Amanda Miranda Franco, Antonio Linkoln Alves Borges Leal, Humberto Medeiros Barreto, Anderson Oliveira Lobo and Fernanda Roberta Marciano

Ceramics 2026, 9(1), 4; https://doi.org/10.3390/ceramics9010004 - 31 Dec 2025

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Abstract

This manuscript describes the development of a nano-sized synthetic smectic clay hydrogel (LAP) that enables controlled oxygen delivery, making it a promising candidate for treating skin wound infections and promoting healing. LAP is an ingredient in various dermatological products, including powders, creams and [...] Read more.

This manuscript describes the development of a nano-sized synthetic smectic clay hydrogel (LAP) that enables controlled oxygen delivery, making it a promising candidate for treating skin wound infections and promoting healing. LAP is an ingredient in various dermatological products, including powders, creams and emulsions. We investigated the antibacterial effect of the LAP hydrogel by incorporating calcium peroxide (CPO), an oxygen-releasing agent, and measuring the size of the inhibitory halo. We found that CPO hydrogels in LAP showed a significant increase in oxygen release during the first five hours, especially at low CPO concentrations. For example, the hydrogel with 5% CPO showed a controlled release profile with a final percentage oxygen release of 2.47 ± 0.01% after 5 h. In contrast, the hydrogels with 10% and 20% CPO achieved lower final oxygen release values, 0.67 ± 0.01% and 0.75 ± 0.01%, respectively, suggesting that the encapsulation efficiency of LAP is higher at higher concentrations. LAP also proved to be an effective oxygen barrier and showed inherent antimicrobial activity. The research confirmed the antibacterial properties of the hydrogel, with inhibition sites observed against both E. coli and S. aureus. These results emphasize the potential of this hydrogel to serve as an effective tool for wound treatment by providing sustained oxygenation and fighting microbial infections. Full article

(This article belongs to the Special Issue Cutting-Edge Research on Bioceramics for Bone Regeneration)

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13 pages, 737 KB

Open AccessArticle

Effect of Thermomechanical Loading on the Marginal Precision of Different Lithium-Based Glass-Ceramic Onlay Restorations

by Ahmed H. Albaqawi, Mohamed F. Metwally, Sami A. Almohefer, Walid A. Abdelhady, Moazzy I. Almansour, Khaled M. Haggag, Hend M. El Sayed, Ferdous Bukhary and Ahmed A. Madfa

Ceramics 2026, 9(1), 3; https://doi.org/10.3390/ceramics9010003 - 31 Dec 2025

Viewed by 1283

Abstract

This in vitro investigation evaluated the marginal fit of three pressable glass-ceramic onlay materials: a conventional monolithic lithium disilicate (IPS e.max Press, EM, ivoclar vivadent AG, Schaan, Liechtenstein) and two zirconia-reinforced glass-ceramics (Vita Ambria, VA, VITA Zahnfabrik, Bad Säckingen, Germany; Celtra Press, CP, [...] Read more.

This in vitro investigation evaluated the marginal fit of three pressable glass-ceramic onlay materials: a conventional monolithic lithium disilicate (IPS e.max Press, EM, ivoclar vivadent AG, Schaan, Liechtenstein) and two zirconia-reinforced glass-ceramics (Vita Ambria, VA, VITA Zahnfabrik, Bad Säckingen, Germany; Celtra Press, CP, Sirona Dentsply, Milford, CT, USA). A typodont maxillary first premolar was prepared for an intensive onlay design by a single operator using a milling surveyor. The master die was duplicated with silicone impressions to create 72 identical epoxy resin dies. Seventy-two onlays (n = 24 per material) were fabricated and adhesively cemented to their respective dies. Vertical marginal gaps were recorded under a stereo-electron microscope before and after thermomechanical loading (TML) in a chewing simulator. Data were analyzed with one-way ANOVA and Tukey’s post hoc tests for intergroup comparisons and paired t-tests for pre- versus post-TML values. All groups showed a significant increase in marginal gap following TML. VA exhibited mean gaps of 46.41 µm before and 57.28 µm after loading (p = 0.001). EM demonstrated 41.16 µm before and 46.63 µm after TML (p = 0.002). CP showed 45.70 µm before and 55.99 µm after TML (p = 0.003). Among the three materials, EM maintained the most accurate marginal adaptation both before and after simulated chewing. Despite the increases, all post-loading values remained within the clinically acceptable threshold for marginal discrepancy. These findings indicated that thermomechanical fatigue adversely affected the marginal integrity of pressable glass-ceramic onlays, including zirconia-reinforced formulations. Nevertheless, zirconia-reinforced ceramics (VA and CP) achieved marginal gaps comparable to conventional lithium disilicate and remained within acceptable clinical limits. IPS e.max Press provided the best overall fit, suggesting it may offer superior long-term marginal stability for onlay restorations. Full article

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16 pages, 17852 KB

Open AccessArticle

The Influence of Graphene Oxide Concentration and Sintering Atmosphere on the Density, Microstructure, and Hardness of Al₂O₃ Ceramics Obtained by the FFF Method

by Ekaterina Kuznetsova, Anton Smirnov, Nestor Washington Solís Pinargote, Roman Khmyrov, Daniil Strunevich, Natella Krikheli, Oleg O. Yanushevich, Pavel Peretyagin and Andrey V. Gusarov

Ceramics 2026, 9(1), 2; https://doi.org/10.3390/ceramics9010002 - 26 Dec 2025

Cited by 2 | Viewed by 1768

Abstract

Highly filled (78 wt.%) alumina filaments with various (0.05, 0.10, 0.25 vol.%) graphene oxide concentration for Fused Filament Fabrication (FFF) were obtained. In order to evaluate the effect of graphene oxide on density, microstructure, and hardness, the fabricated materials were sintered in an [...] Read more.

Highly filled (78 wt.%) alumina filaments with various (0.05, 0.10, 0.25 vol.%) graphene oxide concentration for Fused Filament Fabrication (FFF) were obtained. In order to evaluate the effect of graphene oxide on density, microstructure, and hardness, the fabricated materials were sintered in an argon atmosphere at 1500 °C and 1550 °C. A sample that was sintered under the same conditions in air was used as a control. Raman spectroscopy confirmed the reduction in graphene oxide and the absence of carbon in samples sintered in argon and air, respectively. In addition, in the samples with graphene oxide, the alumina grain size was lower than in air-sintered samples. The composite with the lowest amount (0.05 vol.%) of graphene oxide showed the highest value (1670.73 ± 136.9 HV) hardness. Full article

(This article belongs to the Special Issue Advances in Ceramics, 3rd Edition)

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26 pages, 6721 KB

Open AccessArticle

Nanocrystalline Ceramics Close to Stoichiometric MgAl₂O₄—Overview and Comparison of Traditional Manufacturing Processes with Crystallization Processes at High Pressure

by Astrid Holzheid, Stefanie Hildebrandt, Eleonora Kulik, Bernhard Durschang, Catherine A. Macris, David W. Wallington and Klaus-Dieter Schicke

Ceramics 2026, 9(1), 1; https://doi.org/10.3390/ceramics9010001 - 21 Dec 2025

Viewed by 1385

Abstract

Three processes for the production of ceramics close to stoichiometric MgAl₂O₄ are benchmarked against each other. The traditional ceramic route is based on mostly crystalline starting powder, which is converted into ceramic via shaping and heat treatment (IKTS). The other [...] Read more.

Three processes for the production of ceramics close to stoichiometric MgAl₂O₄ are benchmarked against each other. The traditional ceramic route is based on mostly crystalline starting powder, which is converted into ceramic via shaping and heat treatment (IKTS). The other two processes are based on glasses. Partial or complete crystallization without pressure (ISC) or complete crystallization with pressure (CAU) leads to (glass) ceramics. Spinel powder is mixed with various dopants (BaO, TiO₂, CaO and SrO), with the aim to reduce the grain size (IKTS). The doping results in a second, partly interfering phase, and the transmission decreases strongly due to absorption with increasing content of the added oxide. For the glass route without pressure (ISC), it is shown that a network-forming oxide (B₂O₃, TiO₂) is needed to produce the glasses. Compared to the starting glasses, the resultant glass ceramics suffer loss of transparency due to crystallization. Using the levitation furnace, it is possible to produce amorphous glass beads from MgAl₂O₄ enriched with 25 wt% SiO₂ without a container. The nanocrystalline ceramics synthesized from these glasses and the ISC glasses via the high-pressure route (CAU) are moderately transparent to translucent. Full article

(This article belongs to the Special Issue New Horizons in Ceramic Processing and Manufacturing: Celebrating the Institute for Manufacturing Technologies of Ceramic Components and Composites of the University of Stuttgart)

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Ceramics, Volume 9, Issue 1 (January 2026) – 10 articles

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