Hasil untuk "Clay industries. Ceramics. Glass"

. A. Chaika, G. Mancardi, O. M. Vovk

Optical ceramics of yttrium aluminum garnet (Y3-xCaxAl4.95Cr0.05O12) doped with 0.1 at.% of chromium ions and 0.5, 0.8, and 1.2 at.% of calcium ions were prepared by reactive sintering in vacuum at 1750 degrees C. The influence of SiO2 and CaO sintering aids on the optical properties and microstructure of Cr,Ca:YAG ceramics was investigated. A decrease in CaO concentration led to a reduction of Cr,Ca:YAG transparency from 81 to 0 percent at 1064 nm; moreover, ceramics with lower CaO content exhibited abnormal grains and high porosity. These features were attributed to interactions between silica and calcium oxide during vacuum sintering. Two mechanisms are proposed to explain the effect of CaO and SiO2 on the formation of Ca,Cr:YAG ceramics. The first involves the formation of a liquid phase due to the CaO-SiO2 interaction during the heating stage, resulting in abnormal grain growth. The second mechanism is the mutual consumption of Si4+ and Ca2+ ions during the isothermal stage of sintering, which leads to a decrease in Cr4+ concentration. Both mechanisms negatively affect the optical and laser properties of the ceramics.

Monica Ferraris, Stefano De la Pierre, Valentina Casalegno et al.

Silicon carbide fiber-reinforced composites (SiC/SiC) are leading candidates to replace zirconium-based alloys as cladding in light water reactors (LWR), owing to their exceptional oxidation resistance and mechanical performance under accident conditions.However, pressure-less joining methods compatible with the extreme chemical and thermal environment of LWRs remain a major technological hurdle.This work evaluates two promising joining materials—Mo-wrap (a MoSi₂/Si composite) and SAY (a silica–alumina–yttria glass-ceramic)—under simulated LWR conditions.Joining was performed using both conventional furnaces and laser-assisted techniques.Joint integrity and microstructure were assessed by SEM/EDS and X-ray computed tomography. Hydrothermal stability was evaluated in static and flowing-water (loop) autoclaves up to 30 days at 330 °C and 150–155 bar.Mo-wrap joints showed partial degradation due to silicon dissolution, while SAY joints retained good structural integrity in static tests but suffered phase-selective corrosion under flowing conditions, with keivite emerging as the most stable crystalline phase.Laser-processed amorphous SAY joints exhibited improved corrosion resistance, though still limited under prolonged exposure.These findings advance the understanding of joining performance in nuclear-relevant environments and support the development of accident-tolerant fuel cladding.

Haoxuan Wang, Yifan Wang, Xu Liang et al.

Dislocations are line defects in crystalline solids and often exert a significant influence on the mechanical properties of metals. Recently, there has been a growing interest in using dislocations in ceramics to enhance materials performance. However, dislocation engineering has frequently been deemed uncommon in ceramics owing to the brittle nature of ceramics. Contradicting this conventional view, various approaches have been used to introduce dislocations into ceramic materials without crack formation, thereby paving the way for controlled ceramics performance. However, the influence of dislocations on functional properties is equally complicated owing to the intricate structure of ceramic materials. Furthermore, despite numerous experiments and simulations investigating dislocation-controlled properties in ceramics, comprehensive reviews summarizing the effects of dislocations on ceramics are still lacking. This review focuses on some representative dislocation-controlled properties of ceramic materials, including mechanical and some key functional properties, such as transport, ferroelectricity, thermal conductivity, and superconducting properties. A brief integration of dislocations in ceramic is anticipated to offer new insights for the advancement of dislocation engineering across various disciplines.

Afia Yasmin, Bristy Biswas, Md. Lutfor Rahman et al.

CoFe2O4 was synthesized at 150 °C, 180 °C, and 210 °C temperatures using hydrothermal method to find the effect on its structural, magnetic, electric, and optical properties. The saturation magnetization, coercivity and magnetic anisotropy was found using Vibrating Sample Magnetometer (VSM), ranging from 50.36 to 53.66 emu/g. XRD (X-ray Diffraction Analysis) and SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared Spectroscopy) was used for structural analysis verifying the spinel ferrite structure with a single phase. The crystalline size and lattice strain was found using Size-Strain Plot (SSP) and Debye-Scherrer (D-S) method which proved that as the synthesis temperature increased, the crystallite size also increased. The crystalline size ranges from 39.40 to 82.24 nm as observed by XRD. SEM analysis found the crystal size range to be from 9 to 12 nm. It was found that the optimum temperature to synthesize cobalt ferrite nanoparticles are at 180 °C for sample H2 with a crystal size of 82.24 nm and band gap energy of 2.60 eV. The Ms value was determined to be 50.36 emu/g for H2 sample with Rs value of 0.31.

Mengru Li, Zhenya Zhang, Xianyi Zeng et al.

T. Ibn-Mohammed, N. Bhanot, A.H. Mohammed et al.

Longwen Zhang, Ziyu Wang, Qixuan Zhang et al.

In the realm of digital creativity, our potential to craft intricate 3D worlds from imagination is often hampered by the limitations of existing digital tools, which demand extensive expertise and efforts. To narrow this disparity, we introduce CLAY, a 3D geometry and material generator designed to effortlessly transform human imagination into intricate 3D digital structures. CLAY supports classic text or image inputs as well as 3D-aware controls from diverse primitives (multi-view images, voxels, bounding boxes, point clouds, implicit representations, etc). At its core is a large-scale generative model composed of a multi-resolution Variational Autoencoder (VAE) and a minimalistic latent Diffusion Transformer (DiT), to extract rich 3D priors directly from a diverse range of 3D geometries. Specifically, it adopts neural fields to represent continuous and complete surfaces and uses a geometry generative module with pure transformer blocks in latent space. We present a progressive training scheme to train CLAY on an ultra large 3D model dataset obtained through a carefully designed processing pipeline, resulting in a 3D native geometry generator with 1.5 billion parameters. For appearance generation, CLAY sets out to produce physically-based rendering (PBR) textures by employing a multi-view material diffusion model that can generate 2K resolution textures with diffuse, roughness, and metallic modalities. We demonstrate using CLAY for a range of controllable 3D asset creations, from sketchy conceptual designs to production ready assets with intricate details. Even first time users can easily use CLAY to bring their vivid 3D imaginations to life, unleashing unlimited creativity.

A. Ihyadn, S. Merselmiz, D. Mezzane et al.

Lead-free Ba0.85Ca0.15Zr0.10Ti0.90O3 (BCZT) ceramics with different BaO-Na2O-Nb2O5-WO3-P2O5 (BNNWP) glass content, forming (1-x)BCZT-xBNNWP lead-free ceramics (abbreviated as BCZTx; x=0, 2, 4, 6, and 8wt%) were synthesized using the conventional solid-state processing route. The XRD investigation shows the coexistence of tetragonal and orthorhombic phases in BCZT pure. Likewise, only the tetragonal phase was detected in BCZTx (x = 2-8 wt%) ceramics. The SEM findings indicate that the average grain size decreases as the amount of BNNWP glass additives increases. In addition, BCZT ceramics Amodified with glass additions showed narrower hysteresis loops and a large electric field. The BCZT4 showed the highest recovered energy density of 0.52 J/cm3 at 135kV/cm with an energy storage efficiency of 62.4%, which is increased by 6.6 compared to BCZT0 (0.075 J/cm3). The energy density was also calculated using the Landau-Ginzburg-Devonshire (LGD) theory

Angelica Cardoza, Henry A. Colorado

This study shows an alkaline activated cement (AAC), also known as geopolymer, made from red brick waste with partial addition of Ordinary Portland Cement (OPC). This is a sustainable material since incorporates waste from the brick industry to make cements, therefore increasing the materials circularity and this reducing pollution. The material was cured at room temperature. The brick residue was activated with sodium hydroxide and sodium silicate in aqueous solution to form the hybrid cement. Several mixtures were made with different amounts of waste and proportions of alkaline activator. The mechanical properties of the materials were studied to determine their feasibility to be used in the construction sector. Three contents of OPC were used: 10, 20, and 30 wt%, which were added to improve the mechanical behavior and post-curing time. The activated hybrid cement was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), compression, and flexural tests. The main results show that the addition of OPC to the brick derived AAC produces an increased compressive strength of 106 MPa when 30 wt% OPC was added, a very significant result since the control sample found was 33 MPa in compression strength, an improvement for more than 3 times. The data were corroborated by statistical analysis.

Priya G. Nakade, D. Bhatkhande, Manik Deosarkar et al.

Accessing safe drinking water in India faces a mounting challenge due to deteriorating water quality from industrial pollution and excessive groundwater extraction, leading to increased chemical impurities like fluoride affecting 66 million people across 20 states. Fluoride contamination, arising from natural sources like volcanic activity and mineral weathering, is compounded by industrial discharge from semiconductor, metal, glass, and fertilizer industries. Prolonged exposure to fluoride-laden water poses health risks, causing dental, skeletal, and non-skeletal fluorosis. To address these risks, the World Health Organization (WHO) set the acceptable fluoride limit in drinking water at 1.5 mg/l. Despite various available technologies like coagulation and membrane processes, adsorption remains the most cost-effective method, especially for domestic use. Materials such as alumina, zeolite, clay, coal, and ceramics have been studied as fluoride adsorbents. In present study, laterite, bauxite, hematite, and calcite minerals rich in iron, aluminum, silica, and calcium were examined for fluoride ion adsorption at 7 pH and room temperature. Laterite displayed superior adsorption capacity compared to other minerals. Parameters like stirring speed, adsorbent size, and thermal treatment were investigated for their impact on laterite’s adsorption capacity. Raw laterite was successfully modified by loading it with copper oxide using a copper sulphate solution, significantly elevating its adsorption capacity from 0.26 to 1.905 mg/g, an eight-fold increase. Freundlich isotherm analysis confirmed multilayer adsorption facilitated by electrostatic forces. Isotherm study validates that surface-modified laterite is a robust adsorbent for fluoride removal at neutral pH and room temperature, presenting a promising solution for water treatment needs.

P. Lemougna, A. Ismailov, Erkki Levanen et al.

P. Tihomirovs, A. Korjakins

Recycling glass waste obtained from different industries is an issue in today’s economy. One of the ways of recycling is to produce lightweight ceramic by applying glass waste, clay, and gasifier as raw materials. The present research has been devoted to the evaluation of the influences of different clays extracted from two Latvian quarries (Lielauce un Samini) on the properties of lightweight ceramics. The main criteria of applicated clay as raw materials for producing lightweight ceramic are the following: saturation of SiO2 should be a maximum of 70% and Al2O3 minimum of 12%. The aim of the present research was to elaborate a composition for producing glass ceramic from glass waste with minimum energy consumption with a gasifier. The most important properties of the final product are thermal conductivity, compression strength, volume density, size, granulometry, and pore distribution. Two parameters of them, compression strength and volume density have been tested and analysed in the present research framework. Burning time is one more important additional parameter, which has been considered evaluating the properties of the final product. The obtained volume density is in the range of 226.75 kg/m3 to 475.78 kg/m3 depending on the composition.

G. Mahran

This study aims to treat Nepheline syenite for the glass and ceramics industries. Nepheline syenite has many uses in the glass and ceramics industries. It uses to lower the melting point and fuel savings. In the glass industry, nepheline syenite acts as a source of alumina, which increases resistance to scratching and breaking, improves thermal endurance, and increases chemical durability. A series of processing methods such as dry magnetic separation, flotation, and leaching methods were used respectively to treat nepheline syenite ore. In this paper, the results of combined magnetic, flotation, and leaching Processes of the cleaner concentrate having 0.1% Fe2O3 and 23.25% Al2O3.

Abderrahim Ihyadn, Daoud Mezzane, Mbarek Amjoud et al.

Barium sodium niobate Ba$_2$NaNb$_5$O$_{15}$ (BNN) ceramics with different amounts of BaO-Na$_2$O-Nb$_2$O$_5$-P$_2$O$_5$ (BNNP) glass were prepared via the conventional solid-state method. The effect of glass content on the structural, microstructure, and dielectric properties of BNN ceramics was investigated. The XRD results showed that no secondary phase was formed after adding BNNP glass. It was found that such additions reduce the average grain size and refine the microstructure of the obtained ceramics. Moreover, the samples exhibited a stable dielectric constant over the temperature range of 25$^\circ$C-150$^\circ$C, and their dielectric constants were significantly improved. The ceramic with 7.5 wt% BNNP glass content showed a dielectric constant which is more than twice as much as that of pure BNN ceramic, as well as a low dielectric loss of less than 5%.

Zhilin Tian, Keyu Ming, Liya Zheng et al.

Rare earth (RE) silicate is one of the most promising environmental barrier coatings for silicon-based ceramics in gas turbine engines. However, calcium–magnesium–alumina–silicate (CMAS) corrosion becomes much more serious and is the critical challenge for RE silicate with the increasing operating temperature. Therefore, it is quite urgent to clarify the mechanism of high-temperature CMAS-induced degradation of RE silicate at relatively high temperatures. Herein, the interaction between RE2SiO5 and CMAS up to 1500 ℃ was investigated by a novel high-temperature in-situ observation method. High temperature promotes the growth of the main reaction product (Ca2RE8(SiO4)6O2) fast along the [001] direction, and the precipitation of short and horizontally distributed Ca2RE8(SiO4)6O2 grains was accelerated during the cooling process. The increased temperature increases the solubility of RE elements, decreases the viscosity of CMAS, and thus elevates the corrosion reaction rate, making RE2SiO5 fast interaction with CMAS and less affected by RE element species.

Haoyu Zhang, Shuang Gao, Haitao Guan et al.

<p>Photocatalytic CO₂ reduction to valuable chemical compounds could be a promising approach for carbon-neutral practice. In this work, a simple and robust thermal decomposition process was developed with ammonium carbonate ((NH₄)₂CO₃) as both precipitation agent and sacrificial template to produce fine Nb₂O₅ nanoparticles with the rich existence of surface hydroxyl (–OH) groups. It was found by density functional theory (DFT) calculations and experiments that the rich existence of the surface –OH groups enhanced the adsorption of both reactants (CO₂ and H₂O molecules) for the photocatalytic CO₂ reduction on these fine Nb₂O₅ nanoparticles, and the highly selective conversion of CO₂ to the high-value chemical compound of ethylene (C₂H₄, ~68 μmol·g⁻¹·h⁻¹ with ~100% product selectivity) was achieved under simulated solar illumination without usage of any sacrificial agents or noble metal cocatalysts. This synthesis process may also be readily applied as a surface engineering method to enrich the existence of the surface –OH groups on various metal oxide-based photocatalysts for a broad range of technical applications.</p>

Adeolu Adediran, P. Lemougna, J. Yliniemi et al.

Abstract Concerns about the management of glass wool waste, approximately 800,000 tons of which are generated annually in Europe, are increasing. To test the feasibility of incorporating this waste into ceramic materials, this study examined the reuse of glass wool as a fluxing agent in the production of clay- and waste-based building ceramics. Commercial kaolin clay and two industrial residues, namely quartz-feldspar sand (QFS) and copper slag (CS), were selected as the precursors. Six compositions were prepared, three samples containing glass wool and three counterparts without glass wool, and then sintered at 750, 850, and 950 °C. The materials and prepared ceramics were characterized by employing x-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive x-ray spectroscopy (EDS), differential scanning calorimetry (DSC), water absorption, apparent density, and compressive and flexural strength tests. Interestingly, the results indicated that incorporating 10 wt% of glass wool into the QFS, CS, and kaolin mixtures created ceramics with better physical, mechanical, and microstructural properties. This was ascribed to the glass wool melting reactions observed from approximately 700 °C. The QFS samples with glass wool and sintered at 950 °C achieved compressive strength values as high as 117 MPa and water absorption percentages as low as 2%. However, the fluxing effect of glass wool was less significant in the CS- and kaolin-based ceramics, likely due to differences in their chemical composition, mineralogy, and particle-size distribution. The results of this study emphasize the reuse potential of glass wool and other waste streams in building ceramics and could contribute to improving the management of glass wool waste in line with social sustainability objectives.

P. Tihomirovs, A. Korjakins

Porous ceramics as sustainable material can become and, in some industries, already are used to achieve environmental applications considering their properties. Research on important composition properties helps to identify the best product to be used in construction industry with a priority of a minimum number of raw materials and simplest and energy-efficient technology during production process. The elaborated research identifies compositions with glass waste, clay, and soot with minimum volume density within the range of chosen product line. Water absorption, thermal conductivity, and compressive strength were researched to identify possible applications of elaborated material in construction industry.

P. O. Odewole

In this study, samples of glass-ceramics foam were obtained from granite dust-clay-maize cob composite and chemical additives at low temperature. Effects of the addition of maize cob as the pore-forming agent as well as the chemical additives on the performance properties of the samples of the glass-ceramics foam were investigated. The result of the prepared glass-ceramics foam showed water absorption, apparent porosity, bulk density, compressive strength and thermal conductivity of 25.6–46.7%, 43.5–75%, 1.45–1.9 g/cm3, 0.7–9.7 MPa and 0.11–0.53 W/m.K. respectively. The mechanical and thermo-physical properties as well as microstructural properties of the glass-ceramics foam synthesized in this study provide a feasible indicator that the material can be used in promoting green and sustainable buildings.

Franz Kamutzki, Sven Schneider, Maged Bekeet et al.

This study aims to shed light on processing pathways towards functional silicate ceramics, which show some promise in various emerging applications, including dielectrics and bioactive implant materials. Polycrystalline silicate ceramics of Neso, Soro and Inosilicate families were synthesised by three different techniques: (i) a co-precipitation method, (ii) a modified sol-gel method and (iii) standard solid-state reactions. Co-precipitated samples show increased sintering and densification behaviour compared to sol-gel and solid-state methods, with diametral shrinkage values during sintering of 28.8%, 13.3% and 25.0%, respectively. Well-controlled phase formation in these ceramics was most readily achieved through the steric entrapment of cations and shorter diffusion pathways afforded by the modified Pechini-type sol-gel method. Substituting Zn2+ for Mg2+ in enstatite samples was found to enhance the formation of orthoenstatite during cooling, which is otherwise very slow. We present guidelines for the design of synthesis methods that consider the requirements for different functional silicate ceramics in terms of phase formation and microstructure.