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Ceramics
Volume 5
Issue 1
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Ceramics, Volume 5, Issue 1 (March 2022) – 14 articles

Cover Story (view full-size image): All-ceramic fixed dental prostheses (FDPs) tend to fracture at the connector regions due to high-stress concentration at these areas. The radius of curvature of gingival embrasure is one of the factors that influence the stress distribution and, consequently, longevity of all-ceramic implanted supported FDPs. A comparison was done using three different connector designs to define the most favorable stress distribution using finite element analysis (FEA) based on a patient-retrieved dental prosthesis. FEA is a powerful technique that has been successfully used in dentistry to simulate complex dental structures and various clinical scenarios when different materials are present. View this paper
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12 pages, 1394 KiB  
Review
Porous Zirconia Blocks for Bone Repair: An Integrative Review on Biological and Mechanical Outcomes
by Cláudia Inês Resende-Gonçalves, Nuno Sampaio, Joaquim Moreira, Oscar Carvalho, João Caramês, Maria Cristina Manzanares-Céspedes, Filipe Silva, Bruno Henriques and Júlio Souza
Ceramics 2022, 5(1), 161-172; https://doi.org/10.3390/ceramics5010014 - 17 Mar 2022
Cited by 7 | Viewed by 3856
Abstract
The aim of this study was to conduct an integrative review of the biological and mechanical outcomes of porous zirconia structures for extensive bone repair. An electronic search was performed on the PubMed database using a combination of the following scientific terms: porous, [...] Read more.
The aim of this study was to conduct an integrative review of the biological and mechanical outcomes of porous zirconia structures for extensive bone repair. An electronic search was performed on the PubMed database using a combination of the following scientific terms: porous, scaffold, foam, zirconia, bone regeneration, bone repair, bone healing. Articles published in the English language up to December 2021 and related to porosity, pore interconnectivity, biocompatibility and strength of the material, and the manufacturing methods of zirconia porous structures were included. Randomized controlled trials and prospective cohort studies were also evaluated. The research identified 145 studies, of which 23 were considered relevant. A high percentage of pores and the size and interconnectivity of pores are key factors for cell migration, attachment, proliferation, and differentiation. In addition, pore interconnectivity allows for the exchange of nutrients between cells and formation of blood vessels. However, a decrease in strength of the porous structures was noted with an increase in the number and size of pores. Therefore, yttria-stabilized zirconia tetragonal polycrystal (Y-TZP) has mechanical properties that make it suitable for the manufacture of highly porous structures or implants for extensive bone repair. Additionally, the porous structures can be coated with bioactive ceramics to enhance the cell response and bone ingrowth without compromising pore networking. Porous structures and mesh implants composed of zirconia have become a strategy for extensive bone repair since the material and the pore network provide the desired biological response and bone volume maintenance. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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13 pages, 5207 KiB  
Article
Reinforcement of the Ceramic Matrix of CaO-ZrO2-MgO with Al2O3 Coarse Particles
by João Mamede, Duarte Felix Macedo, Alberto Maceiras and Abílio P. Silva
Ceramics 2022, 5(1), 148-160; https://doi.org/10.3390/ceramics5010013 - 04 Mar 2022
Cited by 3 | Viewed by 2799
Abstract
A thermal protection system is subject to high forces, in particular compression, bending and wear, to aggressive environments of high temperatures, high velocity gases and particle shock. Typically, ceramic materials appear as a first barrier or outer shield over a metallic substrate responsible [...] Read more.
A thermal protection system is subject to high forces, in particular compression, bending and wear, to aggressive environments of high temperatures, high velocity gases and particle shock. Typically, ceramic materials appear as a first barrier or outer shield over a metallic substrate responsible for the structure. When it comes to a coating due to the small thickness, the particles of the raw material are sub-micron scale, but when a shield with a few centimeters is built its structural and economic viability requires the use of wider particle size distributions. In this work, a ceramic fine-grained matrix of CaO-ZrO2-MgO was reinforced with commercial coarse Al2O3 particles. The results show that for larger size distributions, CZM-4A, replacing 63% of fine-grained matrix by coarse Al2O3 particles, the dimensional stability is obtained (ΔL = 5%) and the good mechanical properties such as flexural strength of 154 MPa, elastic modulus of 286 GPa, and hardness of 8.5 GPa, which allows to propose this ceramic composite for a structural application. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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17 pages, 30415 KiB  
Article
Examining the Interactions of Design Parameters in the LDM of Clay as the Basis for New Design Paradigms
by Christina Klug and Thomas H. Schmitz
Ceramics 2022, 5(1), 131-147; https://doi.org/10.3390/ceramics5010012 - 25 Feb 2022
Cited by 3 | Viewed by 3065
Abstract
In the future, architects will not only develop digital designs based on existing technologies and concepts, but will also pursue and experiment with various forms of self-developed processes. The following empirical study deals with the materialization of digital instructions and machine parameters in [...] Read more.
In the future, architects will not only develop digital designs based on existing technologies and concepts, but will also pursue and experiment with various forms of self-developed processes. The following empirical study deals with the materialization of digital instructions and machine parameters in 3D-printed clay elements. Specifically, forms of materialization are investigated in the transitional area where ideal geometrically defined data and process-related material information intersect. Liquid materials generate additional information quality through their material-immanent shape-forming properties. In previous studies, this somewhat complex material behavior was considered rather problematic and attempts were made to reduce the flow behavior of materials in the printing process. In contrast, this study examines the special possibility of liquid deposition modelling and present new ways of dealing with the material viscosity during and after the printing process. Full article
(This article belongs to the Special Issue Additive Manufacturing of Ceramic-based Materials)
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11 pages, 2702 KiB  
Article
Foam-Replicated Diopside/Fluorapatite/Wollastonite-Based Glass–Ceramic Scaffolds
by Francesco Baino, Dilshat U. Tulyaganov, Ziyodilla Kahharov, Abbas Rahdar and Enrica Verné
Ceramics 2022, 5(1), 120-130; https://doi.org/10.3390/ceramics5010011 - 21 Feb 2022
Cited by 9 | Viewed by 2747
Abstract
Implantation of three-dimensional (3D) bioactive glass-derived porous scaffolds is an effective strategy for promoting bone repair and regeneration in large osseous defect sites. The present study intends to expand the potential of a SiO2–P2O5–CaO–MgO–Na2O–CaF2 [...] Read more.
Implantation of three-dimensional (3D) bioactive glass-derived porous scaffolds is an effective strategy for promoting bone repair and regeneration in large osseous defect sites. The present study intends to expand the potential of a SiO2–P2O5–CaO–MgO–Na2O–CaF2 glass composition, which has already proven to be successful in regenerating bone in both animals and human patients. Specifically, this research work reports the fabrication of macroporous glass–ceramic scaffolds by the foam replica method, using the abovementioned bioactive glass powders as a parent material. The sinter-crystallization of the glass powder was investigated by hot-stage microscopy, differential thermal analysis, and X-ray diffraction. Scanning electron microscopy was used to investigate the pore–strut architecture of the resultant glass–ceramic scaffolds in which diopside, fluorapatite, and wollastonite crystallized during thermal treatment. Immersion studies in simulated body fluids revealed that the scaffolds have bioactive behavior in vitro; the mechanical properties were also potentially suitable to suggest use in load-bearing bone applications. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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12 pages, 2853 KiB  
Article
Powder Mixture for the Production of Microporous Ceramics Based on Hydroxyapatite
by Tatiana Safronova, Stepan Chichulin, Tatiana Shatalova and Yaroslav Filippov
Ceramics 2022, 5(1), 108-119; https://doi.org/10.3390/ceramics5010010 - 18 Feb 2022
Cited by 2 | Viewed by 3388
Abstract
Powder mixtures with a given molar ratio of Ca/P = 1.67 were prepared under mechanical activation conditions from hydroxyapatite powder Ca10(PO4)6(OH)2 and a 1M aqueous solution of oxalic acid H2C2O4 at [...] Read more.
Powder mixtures with a given molar ratio of Ca/P = 1.67 were prepared under mechanical activation conditions from hydroxyapatite powder Ca10(PO4)6(OH)2 and a 1M aqueous solution of oxalic acid H2C2O4 at a molar ratio of Ca10(PO4)6(OH)2/H2C2O4 = 1:4. The phase composition of obtained powder mixture included brushite (calcium hydrophosphate dihydrate) CaHPO4·2H2O, calcium oxalate monohydrate CaC2O4·H2O in form of whewellite and weddellite, and some quantity of quasi-amorphous phase. This powder mixture was used to produce microporous monophase ceramics based on hydroxyapatite Ca10(PO4)6(OH)2 with apparent density of 1.25 g/cm3 after firing at 1200 °C. Microporosity of sintered ceramics was formed due to the presence of particles with plate-like morphology, restraining shrinkage during sintering. Microporous ceramics based on hydroxyapatite Ca10(PO4)6(OH)2 with the roughness of the surface as a consequence of the created microporosity can be recommended as a biocompatible material for bone defects treatment and as a substrate for bone cell cultivation. Full article
(This article belongs to the Special Issue Ceramic Processing and Sintering)
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9 pages, 1113 KiB  
Article
4-Unit Molar Fixed Partial Dentures Made from Highly Translucent and Multilayer Zirconia Materials: An In Vitro Investigation
by Thomas Strasser, Alois Schmid, Christina Huber and Martin Rosentritt
Ceramics 2022, 5(1), 99-107; https://doi.org/10.3390/ceramics5010009 - 08 Feb 2022
Cited by 4 | Viewed by 3186
Abstract
Background: Modern zirconia blanks for the fabrication of dental CAD/CAM restorations provide a layer structure with color and strength transitions. Variation in the yttria content has a particular effect on the characteristics of the materials. The properties of dental restorations may vary depending [...] Read more.
Background: Modern zirconia blanks for the fabrication of dental CAD/CAM restorations provide a layer structure with color and strength transitions. Variation in the yttria content has a particular effect on the characteristics of the materials. The properties of dental restorations may vary depending on the milling position within the blank. Especially for wide-span fixed partial dentures (FPDs), relevant effects on clinical performance might result. This study investigated if the application of high-translucent zirconia and positioning within multilayer zirconia blanks affect the in vitro performance of 4-unit FPDs. Methods: 4-unit FPDs were fabricated from monolayer 3Y-TZP-A, 3Y-TZP, 4Y-TZP, 5Y-TZP, 4Y/5Y-TZP, and different positions within multilayer zirconia blanks (3Y-TZP/5Y-TZP). The FPDs were adhesively luted to resin abutment teeth, divided into groups (n = 8 each): “baseline” (24 h water-storage)/“TCML” (chewing simulation by means of thermalcycling and mechanical loading), and loaded to fracture. The statistics included mean and standard deviation, one-way ANOVA, Bonferroni post hoc test, and Pearson correlation (α = 0.05). Results: The mean fracture force values varied between 803.8 ± 171.7 N (5Y) and 1474.1 ± 193.0 N (3Y) (baseline) and 713.5 ± 190.9 N (5Y) and 1337.4 ± 205.6 N (3Y) (TCML). Significantly different (p = 0.000) results between the groups and individual significant differences (p ≤ 0.039) were found. Conclusions: Positioning within multilayer blanks affected the fracture force only slightly. Multilayer, 3Y-TZP-A, 3Y-TZP, and 4Y-TZP seem appropriate for the clinical application with 4-unit molar FPDs. Application of 5Y-TZP is critical. Full article
(This article belongs to the Special Issue Advanced Structural Ceramics II)
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2 pages, 151 KiB  
Editorial
Acknowledgment to Reviewers of Ceramics in 2021
by Ceramics Editorial Office
Ceramics 2022, 5(1), 97-98; https://doi.org/10.3390/ceramics5010008 - 01 Feb 2022
Viewed by 1954
Abstract
Rigorous peer-reviews are the basis of high-quality academic publishing [...] Full article
22 pages, 4947 KiB  
Article
Comparative Properties of Porous Phyllosilicate-Based Ceramics Shaped by Freeze-Tape Casting
by Kassoum Barry, Gisèle Laure Lecomte-Nana, Mohamed Seynou, Michael Faucher, Philippe Blanchart and Claire Peyratout
Ceramics 2022, 5(1), 75-96; https://doi.org/10.3390/ceramics5010007 - 31 Jan 2022
Cited by 6 | Viewed by 2827
Abstract
Porous phyllosilicate-based ceramics were manufactured by freeze-tape casting from clays of different particle size and morphology in order to characterize their microstructure and stress to rupture changes before and after firing. Three raw clays were selected: HCR (77% Halloysite–10Å), KORS (29% kaolinite), and [...] Read more.
Porous phyllosilicate-based ceramics were manufactured by freeze-tape casting from clays of different particle size and morphology in order to characterize their microstructure and stress to rupture changes before and after firing. Three raw clays were selected: HCR (77% Halloysite–10Å), KORS (29% kaolinite), and KCR kaolin (98% kaolinite). These clays exhibited a monomodal distribution and were used to prepare four slurries, three with each clay material and one consisting of a mixture of KCR and HCR labeled KHCR. After shaping by freeze-tape casting, the porosity and stress to rupture obtained by a biaxial flexural test were collected for disk-like samples after drying and sintering at 1200 °C. Results showed that KCR ceramic materials had the highest biaxial bending strength (70 ± 1.1 MPa) and those from KORS had the highest porosity value (80 ± 1%). SEM observation revealed a difference in microstructure and texture for the manufactured porous ceramic materials. In the KCR ceramic disks, the flattened pores appeared more textured, and the primary mullite crystallites formed a rigid skeleton within the amorphous phase. KORS ceramic materials showed a small quantity of secondary mullite needles which were randomly dispersed in a vitreous phase. The relatively important vitreous phase in the porous materials of HCR led to the bulk formation of small mullite particles. The biaxial flexural strength values were related to the presence of the mullite, as well as to the microstructure (volume, morphology, and size distribution of pores) after sintering. Full article
(This article belongs to the Topic Industrial Application of Clays and Clay Minerals)
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20 pages, 8554 KiB  
Article
Sinterability, Mechanical Properties and Wear Behavior of Ti3SiC2 and Cr2AlC MAX Phases
by Eduardo Tabares, Michael Kitzmantel, Erich Neubauer, Antonia Jimenez-Morales and Sophia A. Tsipas
Ceramics 2022, 5(1), 55-74; https://doi.org/10.3390/ceramics5010006 - 31 Jan 2022
Cited by 7 | Viewed by 2989
Abstract
MAX phases are a promising family of materials for several demanding, high-temperature applications and severe conditions. Their combination of metallic and ceramic properties makes MAX phases great candidates to be applied in energy production processes, such as high temperature heat exchangers for catalytic [...] Read more.
MAX phases are a promising family of materials for several demanding, high-temperature applications and severe conditions. Their combination of metallic and ceramic properties makes MAX phases great candidates to be applied in energy production processes, such as high temperature heat exchangers for catalytic devices. For their successful application, however, the effect of the processing method on properties such as wear and mechanical behavior needs to be further established. In this work, the mechanical and wear properties of self-synthesized Ti3SiC2 and Cr2AlC MAX phase powders consolidated by different powder metallurgy routes are evaluated. Uniaxial pressing and sintering, cold isostatic pressing and sintering and hot pressing were explored as processing routes, and samples were characterized by analyzing microstructure, phase constitution and porosity. Wear behavior was studied by reciprocating-sliding tests, evaluating the wear rate by the loss of material and the wear mechanism. Full article
(This article belongs to the Special Issue Ceramic Processing and Sintering)
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11 pages, 4942 KiB  
Article
Interfacial Reactions between Si and SiO2 with Ceramic Additives
by Yu-Hsiang Chen, Kun-Lin Lin and Chien-Cheng Lin
Ceramics 2022, 5(1), 44-54; https://doi.org/10.3390/ceramics5010005 - 28 Jan 2022
Viewed by 2796
Abstract
In this study, 10 wt.% ceramics—Al2O3, La2O3, Y2O3, MgO, and TiO2—were employed as additives for amorphous SiO2 after pressing and annealing at 1300 °C. The amorphous SiO2 [...] Read more.
In this study, 10 wt.% ceramics—Al2O3, La2O3, Y2O3, MgO, and TiO2—were employed as additives for amorphous SiO2 after pressing and annealing at 1300 °C. The amorphous SiO2 changed to cristobalite SiO2. Through X-ray diffraction, scanning electron microscopy, and transmission electron microscopy with energy-dispersive spectrometry, the reaction phases of La2Si2O7, Y2Si2O7, and MgSiO3 (Mg2SiO4) were found in the SiO2 with 10 wt.% La2O3, Y2O3, and MgO additives. Cracks formed in the Si and SiO2–ceramic additive sites because of the difference in the coefficients of thermal expansion among the Si, SiO2, ceramic additives, and reaction phases. After Si came into contact with the SiO2–ceramics, two types of microstructures were found: those with and those without an amorphous SiO2 reaction layer at the interface. Amorphous SiO2 layer formation is due to the replacement of the Si position in SiO2 by Al3+ and Ti4+ impurities, which can break the bonds between Si atoms. The O content in the Si decreased from 6–9 × 1017 atoms/cm3 for SiO2 to less than ~1016 for SiO2–Al2O3 and SiO2–MgO. The average resistivity of the Si was 3 Ω·cm for SiO2 and decreased to 0.12–0.36 Ω·cm for the SiO2 with ceramic additives. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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10 pages, 3075 KiB  
Article
Three-Dimensional Finite Element Analysis of Different Connector Designs for All-Ceramic Implant-Supported Fixed Dental Prostheses
by Laura H. J. Alberto, Lohitha Kalluri, Josephine F. Esquivel-Upshaw and Yuanyuan Duan
Ceramics 2022, 5(1), 34-43; https://doi.org/10.3390/ceramics5010004 - 05 Jan 2022
Cited by 4 | Viewed by 3479
Abstract
All-ceramic fixed dental prostheses (FDPs) tend to fracture at the connector regions due to high stress concentration at these areas influenced by their design. This study was performed as an adjunct to an existing clinical study to evaluate the influence of the different [...] Read more.
All-ceramic fixed dental prostheses (FDPs) tend to fracture at the connector regions due to high stress concentration at these areas influenced by their design. This study was performed as an adjunct to an existing clinical study to evaluate the influence of the different radii of curvature of gingival embrasure on the stress distribution of a three-unit all-ceramic implanted supported FDP. Three three-dimensional (3D) models were created by scanning two titanium dental implants, their suitable zirconia abutments, and a patient-retrieved dental prosthesis using a micro-CT scanner. The radius of curvature of the gingival embrasure for the distal connector of the FDP was altered to measure 0.25 mm, 0.50 mm, and 0.75 mm. A finite element analysis (FEA) software (ABAQUS) was used to evaluate the impact of different connector designs on the distribution of stresses. Maximum Principal Stress data was collected from the individual components (veneer, framework, and abutments). The radius of curvature of gingival embrasure had a significant influence on the stress distribution at the assessed components. The tensile peak stresses at all structures were highest in the 0.25 mm model, while the 0.50 mm and 0.75 mm models presented similar values and more uniform stress distribution. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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10 pages, 7677 KiB  
Article
Structure and Properties of Highly Porous Alumina-Based Ceramic Materials after Heating by Concentrated Solar Radiation
by Vladimir G. Babashov, Sultan Kh. Suleimanov, Mikhail I. Daskovskii, Evgeny A. Shein and Yurii V. Stolyankov
Ceramics 2022, 5(1), 24-33; https://doi.org/10.3390/ceramics5010003 - 30 Dec 2021
Cited by 1 | Viewed by 2118
Abstract
Three ceramic fibrous materials of the Al2O3-SiO2 system with different densities have been treated using concentrated solar radiation. The experiment was performed using technological capabilities of the Big Solar Furnace in the 2 modes: the first mode includes [...] Read more.
Three ceramic fibrous materials of the Al2O3-SiO2 system with different densities have been treated using concentrated solar radiation. The experiment was performed using technological capabilities of the Big Solar Furnace in the 2 modes: the first mode includes heating up to 1400–1600 °C, holding for 1.5–2 h; the second mode (the fusion mode) includes heating up to 1750–1900 °C until the sample destruction, which is accompanied by fusion. Upon completion of the experiment, the phase composition, microstructure, and compressive strength of the materials were studied. It was shown that the investigated materials retained their fibrous structure under prolonged treatment in the first mode up to temperatures of 1600 °C. The phase composition of the ceramic materials changes during the experiment, and with a decrease in the density, the modification is more pronounced. Treatment of all three materials under study in the fusion mode resulted in the formation of the eutectic component in the form of spherulites. The compressive strength of the materials was found to be slightly reduced after exposure to concentrated solar radiation. Full article
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11 pages, 2915 KiB  
Article
Study of Radiation Embitterment and Degradation Processes of Li2ZrO3 Ceramic under Irradiation with Swift Heavy Ions
by Baurzhan Abyshev, Artem L. Kozlovskiy, Kassym Sh Zhumadilov and Alex V. Trukhanov
Ceramics 2022, 5(1), 13-23; https://doi.org/10.3390/ceramics5010002 - 24 Dec 2021
Cited by 5 | Viewed by 2928
Abstract
The work is devoted to the study of radiation damage and subsequent swelling processes of the surface layer of Li2ZrO3 ceramics under irradiation with heavy Xe22+ ions, depending on the accumulation of the radiation dose. The samples under study [...] Read more.
The work is devoted to the study of radiation damage and subsequent swelling processes of the surface layer of Li2ZrO3 ceramics under irradiation with heavy Xe22+ ions, depending on the accumulation of the radiation dose. The samples under study were obtained using a mechanochemical synthesis method. The samples were irradiated with heavy Xe22+ ions with an energy of 230 MeV at irradiation fluences of 1011–1016 ion/cm2. The choice of ion types is due to the possibility of simulating the radiation damage accumulation processes as a result of the implantation of Xe22+ ions and subsequent atomic displacements. It was found that, at irradiation doses above 5 × 1014 ion/cm2, point defects accumulate, which leads to a disordering of the surface layer and a subsequent decrease in the strength and hardness of ceramics. At the same time, the main process influencing the decrease in resistance to radiation damage is the crystal structure swelling as a result of the accumulation of defects and disordering of the crystal lattice. Full article
(This article belongs to the Special Issue Advances in Ceramics)
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12 pages, 4957 KiB  
Article
Reactive Sintering of Al2O3–Y3Al5O12 Ceramic Composites Obtained by Direct Ink Writing
by Joana Baltazar, Manuel Fellipe Rodrigues Pais Alves, Claudinei dos Santos and Susana Olhero
Ceramics 2022, 5(1), 1-12; https://doi.org/10.3390/ceramics5010001 - 23 Dec 2021
Cited by 7 | Viewed by 3050
Abstract
The main goal of this work was to obtain dense Al2O3–Y3Al5O12 ceramic composites by reactive sintering of three-dimensional samples, built by direct ink writing from a paste containing a mixture of Al2O [...] Read more.
The main goal of this work was to obtain dense Al2O3–Y3Al5O12 ceramic composites by reactive sintering of three-dimensional samples, built by direct ink writing from a paste containing a mixture of Al2O3 and Y2O3 powders. To obtain a ceramic ink with proper rheological properties for extrusion-based printing, highly pure Al2O3 and Y2O3 powders in a percentage–weight ratio of 64:36 was mixed with 0.2 wt% MgO in a total solid loading of 42 vol% in aqueous media, adding carboxymethyl cellulose and polyethyleneimine solution as additives. The dried printed samples were sintered at final temperatures in the range of 1550 °C and 1650 °C; thus, relative densities of 83.7 ± 0.8%, 95.4 ± 0.4%, and 96.5 ± 0.5% were obtained for 1550 °C, 1600 °C, and 1650 °C, respectively. Rietveld refinement performed on the X-ray diffraction patterns indicated the presence of Al2O3 (42 to 47%) and Y3Al15O12 (58 to 61%) as crystalline phases, while micrographs showed the presence of equiaxial micrometric grains with average sizes of 1.8 ± 0.6 μm, for both phases and all sintering conditions. Samples sintered at 1600 °C and 1650 °C presented similar average Vickers hardness values of 14.2 ± 0.27 GPa and 14.5 ± 0.25 GPa, respectively. A slight increase in fracture toughness as sintering temperature increases was also stated, consistent with the densification. Full article
(This article belongs to the Special Issue Advanced Structural Ceramics II)
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