Journal Description
Ceramics
Ceramics
is an international, peer-reviewed, open access journal of ceramics science and engineering, published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), and other databases.
- Journal Rank: CiteScore - Q2 (Materials Science (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.6 days after submission; acceptance to publication is undertaken in 3.6 days (median values for papers published in this journal in the first half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.8 (2022);
5-Year Impact Factor:
2.1 (2022)
Latest Articles
Phase Formation and Properties of Multicomponent Solid Solutions Based on Ba(Ti, Zr)O3 and AgNbO3 for Environmentally Friendly High-Efficiency Energy Storage
Ceramics 2023, 6(3), 1840-1849; https://doi.org/10.3390/ceramics6030112 - 26 Aug 2023
Abstract
This paper investigates the processes of phase formation of solid solutions of (1 − x)BaTi0.85Zr0.15O3 − xAgNbO3 where x = 0, 0.03, 0.06, 0.09. The optimal temperatures of synthesis and sintering are determined. From the
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This paper investigates the processes of phase formation of solid solutions of (1 − x)BaTi0.85Zr0.15O3 − xAgNbO3 where x = 0, 0.03, 0.06, 0.09. The optimal temperatures of synthesis and sintering are determined. From the results of X-ray diffraction analysis, it follows that all solid solutions have a perovskite-type structure. Analysis of the microstructure showed that the average grain size decreases at concentrations x = 0.03 and 0.06. Correlations between the cationic composition and dielectric characteristics of the studied solid solutions have been established. The values of the total stored energy and efficiency are determined. The maximum stored energy was found for a solid solution with x = 0.03 and amounted to 0.074 J∙cm−3 with an efficiency of 76.5%.
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(This article belongs to the Special Issue Advances in Ferroelectric, Construction, Luminescent Ceramics and Crystals)
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An Investigation of Iodovanadinite Wasteforms for the Immobilisation of Radio-Iodine and Technetium
Ceramics 2023, 6(3), 1826-1839; https://doi.org/10.3390/ceramics6030111 - 24 Aug 2023
Abstract
99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a
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99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing.
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(This article belongs to the Special Issue Advances in Ceramics, 2nd Edition)
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Nutrient-Doped Hydroxyapatite: Structure, Synthesis and Properties
Ceramics 2023, 6(3), 1799-1825; https://doi.org/10.3390/ceramics6030110 - 22 Aug 2023
Abstract
Complex inorganic powders based on calcium phosphates have found a plethora of practical applications. Of particular interest are the CaO-P2O5 system-based multi-component material powders and granules as the source of major- and micronutrients for the plants. The emerging strategy is
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Complex inorganic powders based on calcium phosphates have found a plethora of practical applications. Of particular interest are the CaO-P2O5 system-based multi-component material powders and granules as the source of major- and micronutrients for the plants. The emerging strategy is to use nano fertilizers based on hydroxyapatite (HAP) for phosphorus and other nutrient delivery. The doping of micronutrients into HAP structure presents an interesting challenge in obtaining specific phase compositions of these calcium phosphates. Various techniques, including mechanochemical synthesis, have been employed to fabricate doped HAP. Mechanochemical synthesis is of particular interest in this review since it presents a relatively simple, scalable, and cost-effective method of calcium phosphate powder processing. The method involves the use of mechanical force to promote chemical reactions and create nanometric powders. This technique has been successfully applied to produce HAP nanoparticles alone, and HAP doped with other elements, such as zinc and magnesium. Nanofertilizers developed through mechanochemical synthesis can offer several advantages over conventional fertilizers. Their nanoscale size allows for rapid absorption and controlled release of nutrients, which leads to improved nutrient uptake efficiency by plants. Furthermore, the tailored properties of HAP-based nano fertilizers, such as controlled porosity and degradation levels, contribute to their effectiveness in providing plant nutrition.
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(This article belongs to the Special Issue Innovative Research on Calcium Phosphates Based Ceramics)
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Influence of Alkali Metal Ions on the Structural and Spectroscopic Properties of Sm3+-Doped Silicate Glasses
Ceramics 2023, 6(3), 1788-1798; https://doi.org/10.3390/ceramics6030109 - 21 Aug 2023
Abstract
In the present work, the influence of alkali ions (Li, Na, K) on the structural and spectroscopic properties of silica glasses doped with Sm3+ was investigated. Infrared and Raman spectroscopy techniques were used to investigate the structural properties of the alkali silicate
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In the present work, the influence of alkali ions (Li, Na, K) on the structural and spectroscopic properties of silica glasses doped with Sm3+ was investigated. Infrared and Raman spectroscopy techniques were used to investigate the structural properties of the alkali silicate glasses. The optical absorption showed bands characteristic of Sm3+ ions in alkali silicate glasses, and this was investigated. The Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters (Ω2, Ω4, and Ω6) of the optical absorption measurements. The multi-channel visible and near infrared emission transitions originating from the 4G5/2-emitting state of the Sm3+ in alkali silicate glasses with a maximum phonon energy of ~1050 cm−1 were investigated. From the evaluated Judd–Ofelt parameters, radiative parameters such as spontaneous emission probabilities, radiative lifetimes, branching ratios, and stimulated emission cross-sections were calculated. The recorded luminescence spectra regions revealed intense green, orange, red, and near-infrared emission bands, providing new traces for developing tunable laser and optoelectronic devices.
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(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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Alkali-Activated Brick Aggregates as Industrial Valorized Wastes: Synthesis and Properties
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, , , , , , and
Ceramics 2023, 6(3), 1765-1787; https://doi.org/10.3390/ceramics6030108 - 14 Aug 2023
Abstract
In recent works, many industrial by-products were employed as solid precursors for the synthesis of alkali-activated binders and as alternatives to Portland cement for the immobilization of hazardous, toxic and nuclear wastes. Among industrial wastes, alkali-activated brick was found to be an interesting
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In recent works, many industrial by-products were employed as solid precursors for the synthesis of alkali-activated binders and as alternatives to Portland cement for the immobilization of hazardous, toxic and nuclear wastes. Among industrial wastes, alkali-activated brick was found to be an interesting porous composite for removing very toxic heavy metals (Pb2+, Cd2+, Co2+) and radio-nuclides (Sr2+, Cs+, Rb+) from aqueous solutions. The starting material is very attractive due to the presence of metakaolinite as a geo-polymer precursor and silica for increasing material permeability and facilitating water filtration. The alkaline reaction gave rise to geo-polymerization followed by partial zeolitization. Elemental surface micro-analysis was performed by Scanning Electron Microscopy (SEM) equipped with an Energy-Dispersive X-ray Spectrometer (EDS). The formation of crystalline phases was corroborated by X-ray diffraction (XRD) analysis. Information about 29Si, 27Al and 1H nuclei environments in crystallized and amorphous aluminosilicates was obtained by 29Si, 27Al and 1H MAS NMR. 27Al–1H dipolar-mediated correlations were investigated by employing dipolar hetero-nuclear multiple quantum coherence (D-HMQC) NMR, highlighting Al–O–H bonds in bridging hydroxyl groups (Si–OH–Al) that are at the origin of adsorptive properties. Aqueous structural stability and cationic immobilization characteristics before and after material calcination were investigated from acid-leaching experiments.
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(This article belongs to the Special Issue The Production Processes and Applications of Geopolymers)
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Geopolymer Antimicrobial and Hydrophobic Modifications: A Review
Ceramics 2023, 6(3), 1749-1764; https://doi.org/10.3390/ceramics6030107 - 11 Aug 2023
Abstract
The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials,
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The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials, due to their improved mechanical properties, resistance to chemicals, resistance to high temperature, and lower carbon footprint. Like concrete, they are susceptible to microbially induced deterioration (corrosion), especially in a humid environment, primarily due to surface colonization by sulphur-oxidizing bacteria. This paper reviews various methods for hydrophobic or antimicrobial protection by the method of critical analysis of the literature and the results are discussed, along with potential applications of geopolymers with improved antimicrobial properties. Metal nanoparticles, despite their risks, along with PDMS and epoxy coatings, are the most investigated and effective materials for geopolymer protection. Additionally, future prospects, risks, and challenges for geopolymer research and protection against degradation are presented and discussed.
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(This article belongs to the Special Issue The Production Processes and Applications of Geopolymers)
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Structure and Relaxor Behavior of (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 Ternary Ceramics
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, , , , , , and
Ceramics 2023, 6(3), 1735-1748; https://doi.org/10.3390/ceramics6030106 - 08 Aug 2023
Abstract
Ceramics of the quasi-binary concentration section (0.1 ≤ x ≤ 0.2, Δx = 0.025) of the ternary solid solution system (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 were prepared by the conventional solid-phase reaction
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Ceramics of the quasi-binary concentration section (0.1 ≤ x ≤ 0.2, Δx = 0.025) of the ternary solid solution system (0.5 − x)BiFeO3-0.5PbFe0.5Nb0.5O3-xPbTiO3 were prepared by the conventional solid-phase reaction method. An X-ray study at different temperatures revealed that (0.5 − x)BF-0.5PFN-xPT ceramics have a cluster morphology. Clusters have different modulation, crystal lattice symmetry, and chemical composition. The presence of a cluster structure in a solid solution with heterovalent substitution, consisting of regions rich in Ti+4, Nb+5, or Fe3+, has led to the appearance of Maxwell–Wagner polarization in the studied ceramics. The study of the dielectric characteristics revealed the relaxor-like behavior of the studied ceramics. The grain morphology, dielectric, pyroelectric, and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient, d33 = 280 pC/N, was obtained in the 0.3BiFeO3-0.5PbFe0.5Nb0.5O3-0.2PbTiO3 ceramics. Study of the dielectric characteristics of all samples revealed relaxor ferroelectric behavior and a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 140–170 °C.
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(This article belongs to the Special Issue Advances in Ferroelectric, Construction, Luminescent Ceramics and Crystals)
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Zirconia-Based Ceramics Reinforced by Carbon Nanotubes: A Review with Emphasis on Mechanical Properties
Ceramics 2023, 6(3), 1705-1734; https://doi.org/10.3390/ceramics6030105 - 06 Aug 2023
Abstract
This review outlines the state of the art, processing techniques, and mechanical testing methods of zirconia (ZrO2)-based composites reinforced by carbon nanotubes (CNTs). The use of CNTs as a secondary phase in a zirconia matrix is motivated by their outstanding crack
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This review outlines the state of the art, processing techniques, and mechanical testing methods of zirconia (ZrO2)-based composites reinforced by carbon nanotubes (CNTs). The use of CNTs as a secondary phase in a zirconia matrix is motivated by their outstanding crack self-healing ability, the possibility to tailor the desired nano-structural properties, and their exceptional wear behavior. Therefore, a detailed investigation into CNT features has been provided. The debate of using the different Vickers indentation fracture toughness equations to estimate the resistance of crack propagation was critically reviewed according to crack characteristics. Finally, this review particularly highlights the exceptional role of ZrO2-based composites as a promising material owing to their outstanding tribo-mechanical properties.
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(This article belongs to the Special Issue Ceramic Processing and Sintering, Volume II)
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Unlocking the Potential of Biomass Fly Ash: Exploring Its Application in Geopolymeric Materials and a Comparative Case Study of BFA-Based Geopolymeric Concrete against Conventional Concrete
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, , , , , and
Ceramics 2023, 6(3), 1682-1704; https://doi.org/10.3390/ceramics6030104 - 03 Aug 2023
Abstract
The production of conventional cement involves high energy consumption and the release of substantial amounts of carbon dioxide (CO2), exacerbating climate change. Additionally, the extraction of raw materials, such as limestone and clay, leads to habitat destruction and biodiversity loss. Geopolymer
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The production of conventional cement involves high energy consumption and the release of substantial amounts of carbon dioxide (CO2), exacerbating climate change. Additionally, the extraction of raw materials, such as limestone and clay, leads to habitat destruction and biodiversity loss. Geopolymer technology offers a promising alternative to conventional cement by utilizing industrial byproducts and significantly reducing carbon emissions. This paper analyzes the utilization of biomass fly ash (BFA) in the formation of geopolymer concrete and compares its carbon and cost impacts to those of conventional concrete. The previous analysis shows great potential for geopolymers to reduce the climate change impact of cement production. The results of this analysis indicate a significant disparity in the computed financial and sustainability costs associated with geopolymers. Researchers have shown that geopolymers may help mitigate the effects of cement manufacturing on the environment. These geopolymers are predicted to reduce green gas emissions by 40–80%. They also show that those advantages can be realized with the best possible feedstock source and the cheapest possible conveyance. Furthermore, our case study on CO2 emission and cost calculation for BFA-based geopolymer and conventional concrete shows that geopolymer concrete preparation emits 56% less CO2 than conventional concrete while costing 32.4% less per ton.
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(This article belongs to the Special Issue The Production Processes and Applications of Geopolymers)
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Porous Ceramic ZnO Nanopowders: Features of Photoluminescence, Adsorption and Photocatalytic Properties
Ceramics 2023, 6(3), 1667-1681; https://doi.org/10.3390/ceramics6030103 - 02 Aug 2023
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The grainy and porous ZnO powders were synthesized by thermal decomposition of zinc nitrate and polymer-salt method. The comparative study of the crystal structure, morphology, luminescence, adsorptive and photocatalytic properties of ZnO powders was carried out. The addition of PVP in initial aqueous
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The grainy and porous ZnO powders were synthesized by thermal decomposition of zinc nitrate and polymer-salt method. The comparative study of the crystal structure, morphology, luminescence, adsorptive and photocatalytic properties of ZnO powders was carried out. The addition of PVP in initial aqueous solutions of zinc nitrate determines the remarkable change of powder morphology and decreases the average size of ZnO nanocrystals. Luminescence spectra in the visible spectral range indicate the significant difference of structural defects types in grainy and porous powders. Porous powders demonstrate high ability for singlet oxygen photogeneration and photocatalytic properties. The kinetics of diazo dye adsorption on both powders is described successfully by the kinetic equation of pseudo-second order. Kinetic dependencies of photocatalytic oxidation of Chicago Sky Blue diazo dye using as grain ZnO powder so as porous ZnO powders are described by the Langmuir–Hinshelwood model but process rates are different. Porous ZnO powder demonstrates strong ability for photogeneration of singlet oxygen under visible irradiation and high photocatalytic properties (rate constant 0.042 min−1).
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Synthesis and Characterization of Nd:YAG Ceramics for Laser Applications
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Ceramics 2023, 6(3), 1655-1666; https://doi.org/10.3390/ceramics6030102 - 02 Aug 2023
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Materials known as Nd:YAG are crystalline materials of the cubic system made from the neodymium-doped yttrium aluminum garnet, which, among others, have excellent optical properties. Nd:YAG four-level laser devices are frequently used in both the health and industrial sectors. In this study, a
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Materials known as Nd:YAG are crystalline materials of the cubic system made from the neodymium-doped yttrium aluminum garnet, which, among others, have excellent optical properties. Nd:YAG four-level laser devices are frequently used in both the health and industrial sectors. In this study, a simple and inexpensive alternative to manufacturing Nd:YAG materials through solid state reactions following powder processing routes was proposed. For this, an intense mixture of the precursor materials (Al2O3 and Y2O3) was carried out, followed by the addition of neodymium atoms to improve the optical properties of the resulting material. High-energy mechanical mixing of the precursor powders resulted in submicron particles with good size distributions of the powders. The advance of YAG formation was monitored by intermediate phase formation during heat treatment through interrupted tests at different temperatures and analysis by X-ray diffraction. From this analysis, it was found that reaction for the formation of the desired YAG is completed at 1500 °C. Fourier transform infrared spectroscopy analyses determined the presence of functional groups corresponding to the YAG. Finally, the study employing optical emission spectroscopy showed wavelengths in agreement with those of the electronic structure of the elements of the synthesized Nd:YAG.
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Water-Glass-Assisted Foaming in Foamed Glass Production
Ceramics 2023, 6(3), 1646-1654; https://doi.org/10.3390/ceramics6030101 - 02 Aug 2023
Abstract
The energy efficiency of buildings can be greatly improved by decreasing the energy embodied in installed materials. In this contribution, we investigated the possibility of foaming waste bottle glass in the air atmosphere with the addition of water glass, which would reduce the
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The energy efficiency of buildings can be greatly improved by decreasing the energy embodied in installed materials. In this contribution, we investigated the possibility of foaming waste bottle glass in the air atmosphere with the addition of water glass, which would reduce the energy used in the production of foamed glass boards. The results show that with the increased addition of water glass, the crystallinity and the thermal conductivity decrease, however, the remaining crystal content prevents the formation of closed-porous foams. The added water glass only partly protects the carbon from premature oxidation, and the foaming mechanism in the air is different than in the argon atmosphere. The lowest obtained foam density in the air atmosphere is 123 kg m−3, while the lowest thermal conductivity is 53 mW m−1 K−1, with an open porosity of 50% for the sample obtained in the air, containing 12 wt% of water glass, 2 wt% of B2O3, 2 wt% AlPO4 and 2 wt% K3PO4.
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(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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Effect of Diamond Phase Dispersion on the Properties of Diamond-SiC-Si Composites
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, , , and
Ceramics 2023, 6(3), 1632-1645; https://doi.org/10.3390/ceramics6030100 - 28 Jul 2023
Abstract
The research aimed at the composition optimization for diamond-SiC-Si composites. The effect of a porous diamond workpiece was studied on the properties (porosity, density, modulus of elasticity, phase composition) of the product of its siliconization with molten silicon. The lowest porosity and highest
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The research aimed at the composition optimization for diamond-SiC-Si composites. The effect of a porous diamond workpiece was studied on the properties (porosity, density, modulus of elasticity, phase composition) of the product of its siliconization with molten silicon. The lowest porosity and highest modulus of elasticity were observed in the case of using mixed matrices with the maximum size of diamond grains of 250/200 μm for siliconization. The best results in terms of the sound speed (16,600 m/s) and elasticity modulus (860 GPa) were achieved by microwave processing of a composite containing detonation nanodiamonds.
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(This article belongs to the Special Issue Composite Nanopowders: Synthesis and Applications)
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Phase Composition and Magnetic Properties of Nanoparticles with Magnetite–Maghemite Structure
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Ceramics 2023, 6(3), 1623-1631; https://doi.org/10.3390/ceramics6030099 - 18 Jul 2023
Abstract
Precipitation of nanopowders with mixed magnetite–maghemite composition was carried out under different conditions and with different separation techniques. The exact character of interactions of different iron oxide phases in the nanopowder was the main object of interest. The obtained nanopowders have spherical particles
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Precipitation of nanopowders with mixed magnetite–maghemite composition was carried out under different conditions and with different separation techniques. The exact character of interactions of different iron oxide phases in the nanopowder was the main object of interest. The obtained nanopowders have spherical particles about 10–20 nm in size. Electron paramagnetic resonance (EPR) study showed that iron ions incorporate fully into magnetite and maghemite structures. The shape of the EPR line points out that single homogenous solid solutions were formed during synthesis. In the studied solid solutions, different ratios of vacancies and Fe2+/Fe3+ ratios were observed but in spite of different synthesis techniques in both cases, there were no additional diamagnetic structural phases presented.
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(This article belongs to the Special Issue Composite Nanopowders: Synthesis and Applications)
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Zirconolite Matrices for the Immobilization of REE–Actinide Wastes
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Ceramics 2023, 6(3), 1573-1622; https://doi.org/10.3390/ceramics6030098 - 15 Jul 2023
Abstract
The structural and chemical properties of zirconolite (ideally CaZrTi2O7) as a host phase for separated REE–actinide-rich wastes are considered. Detailed analysis of both natural and synthetic zirconolite-structured phases confirms that a selection of zirconolite polytype structures may be obtained,
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The structural and chemical properties of zirconolite (ideally CaZrTi2O7) as a host phase for separated REE–actinide-rich wastes are considered. Detailed analysis of both natural and synthetic zirconolite-structured phases confirms that a selection of zirconolite polytype structures may be obtained, determined by the provenance, crystal chemistry, and/or synthesis route. The production of zirconolite ceramic and glass–ceramic composites at an industrial scale appears most feasible by cold pressing and sintering (CPS), pressure-assisted sintering techniques such as hot isostatic pressing (HIP), or a melt crystallization route. Moreover, we discuss the synthesis of zirconolite glass ceramics by the crystallization of B–Si–Ca–Zr–Ti glasses containing actinides in conditions of increased temperatures relevant to deep borehole disposal (DBD).
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(This article belongs to the Special Issue Zirconolite Ceramic and Glass-Ceramic Wasteforms)
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Bismuth-Germanate Glasses: Synthesis, Structure, Luminescence, and Crystallization
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Ceramics 2023, 6(3), 1559-1572; https://doi.org/10.3390/ceramics6030097 - 13 Jul 2023
Abstract
Bismuth-germanate glasses, which are well known as a promising active medium for broadband near-infrared spectral range fiber lasers and as an initial matrix for nonlinear optical glass ceramics, have been synthesized in a 5–50 mol% Bi2O3 wide concentration range. Their
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Bismuth-germanate glasses, which are well known as a promising active medium for broadband near-infrared spectral range fiber lasers and as an initial matrix for nonlinear optical glass ceramics, have been synthesized in a 5–50 mol% Bi2O3 wide concentration range. Their structural and physical characteristics were studied by Raman and FT-IR spectroscopy, differential scanning calorimetry, X-ray diffraction, optical, and luminescence methods. It has been found that the main structural units of glasses are [BiO6] and [GeO4]. The growth in bismuth oxide content resulted in an increase in density and refractive index. The spectral and luminescent properties of glasses strongly depended on the amount of bismuth active centers. The maximum intensity of IR luminescence has been achieved for the 5Bi2O3-95GeO2 sample. The heat treatment of glasses resulted in the formation of several crystalline phases, the structure and amount of which depended on the initial glass composition. The main phases were non-linear Bi2GeO5 and scintillating Bi4Ge3O12. Comparing with the previous papers dealing with bismuth and germanium oxide-based glasses, we enlarge the range of Bi2O3 concentration up to 50 mol% and decrease the synthesis temperature from 1300 to 1100 °C.
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(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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Formation and Photophysical Properties of Silver Clusters in Bulk of Photo-Thermo-Refractive Glass
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Ceramics 2023, 6(3), 1546-1558; https://doi.org/10.3390/ceramics6030096 - 13 Jul 2023
Abstract
The bright luminescence of silver clusters in glass have potential applications in solid-state lighting, optical memory, and spectral converters. In this work, luminescent silver clusters were formed in the bulk of photo-thermo-refractive glass (15Na2O-5ZnO-2.9Al2O3-70.3SiO2-6.5F, mol.%)
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The bright luminescence of silver clusters in glass have potential applications in solid-state lighting, optical memory, and spectral converters. In this work, luminescent silver clusters were formed in the bulk of photo-thermo-refractive glass (15Na2O-5ZnO-2.9Al2O3-70.3SiO2-6.5F, mol.%) doped with different Ag2O concentrations from 0.01 to 0.05 mol.%. The spontaneous formation of plasmonic nanoparticles during glass synthesis was observed at 0.05 mol.% of Ag2O in the glass composition, limiting the silver concentration range for cluster formation. The luminescence of silver clusters was characterized by steady-state and time-resolved spectroscopy techniques. The rate constants of fluorescence, phosphorescence, intersystem crossing, and nonradiative deactivation were estimated on the basis of an experimental study. A comparison of the results obtained for the photophysical properties of luminescent silver clusters formed in the ion-exchanged layers of photo-thermo-refractive glass is provided.
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(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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Magnesium Oxide Powder Synthesis in Cathodic Arc Discharge Plasma in an Argon Environment at Atmospheric Pressure
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, , , , , , and
Ceramics 2023, 6(3), 1531-1545; https://doi.org/10.3390/ceramics6030095 - 11 Jul 2023
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Discharges with cathode spots can operate in a wide range of gas pressures. Erosion of the cathode material is an inherent property of such discharges. The erosion products are considered to be ionized atoms and electrically neutral microdroplets. In accordance with this concept,
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Discharges with cathode spots can operate in a wide range of gas pressures. Erosion of the cathode material is an inherent property of such discharges. The erosion products are considered to be ionized atoms and electrically neutral microdroplets. In accordance with this concept, a plasma source based on a pulsed cathodic arc discharge in atmospheric-pressure argon with a current of up to 200 A, a pulse duration of 250 μs, and a pulse repetition rate of 10 Hz was implemented. Using this source, the synthesis of magnesium oxide powder was performed. The chemical composition of the erosion products was determined using the TEM/EDS method and the composition of the gas mixture in which the discharge system operated was evaluated by optical spectrometry. It was shown that particles of the synthesized powder have different morphological features, depending on the nature of the electrical erosion of the cathode material. Micron-sized particles are formed due to the removal of microdroplets from liquid–metal craters on the cathode surface at certain plasma pressures. Submicron particles are produced during the agglomeration of atoms originating from the plasma jets flowing out from cathode spots. These atoms are magnesium ions that are neutralized by collisions with gas particles. The advantages and disadvantages of this synthesis method are discussed in this paper. The reference methods for the powder synthesis of magnesium oxide are compared. The prospects of the studied method from the point of view of its application for obtaining ceramic materials are also evaluated.
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A Review of Cr2+ or Fe2+ Ion-Doped Zinc Sulfide and Zinc Selenide Ceramics as IR Laser Active Media
Ceramics 2023, 6(3), 1517-1530; https://doi.org/10.3390/ceramics6030094 - 11 Jul 2023
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Zinc chalcogenides doped with Cr2+ or Fe2+ ions are of considerable interest as active media for IR lasers operating in the 2–5 µm wavelength range. Such lasers are in demand in various fields of medicine, remote sensing and atmospheric monitoring, ranging,
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Zinc chalcogenides doped with Cr2+ or Fe2+ ions are of considerable interest as active media for IR lasers operating in the 2–5 µm wavelength range. Such lasers are in demand in various fields of medicine, remote sensing and atmospheric monitoring, ranging, optical communication systems, and military applications. In recent years, however, the rate of improvement in the characteristics of zinc chalcogenide laser sources has slowed considerably. Unwanted thermally induced effects, parasitic oscillations, and laser-induced damage of the active element have hindered the scaling of output power and efficiency. However, the physical and chemical properties of the materials leave ample room for further improvements. In particular, the control of the dopant concentration profile in the active element is of great importance. Zero concentration of Cr2+ or Fe2+ ions on the radiation input/output surfaces can significantly increase the laser-induced damage threshold; the designed concentration distribution in the element volume allows regulation of heat dissipation and reduction of parasitic oscillations. The zinc chalcogenide ceramic technology seems to be the most suitable to solve this challenge. This review presents and discusses the state of the art in ZnS and ZnSe optical and laser ceramics and the directions for further development of their technology.
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A Study of PbF2 Nanoparticles Crystallization Mechanism in Mixed Oxyde-Fluoride Glasses
Ceramics 2023, 6(3), 1508-1516; https://doi.org/10.3390/ceramics6030093 - 11 Jul 2023
Abstract
Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using
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Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using small-angle X-ray scattering and X-ray diffraction methods. The enlargements of the average sizes of nanoparticles and the sizes of local areas of density fluctuations have been found to be correlated with an increase in concentrations of Ho2O3 and Tm2O3 in initial glasses. A variation in the concentrations of Ho2O3 and Tm2O3 does not affect the morphology and fractal dimension of the formed PbF2 nanoparticles.
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(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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