Hasil untuk "Clay industries. Ceramics. Glass"

Blanka Seredynska, Karolina Korycka, Radoslaw Zurowski et al.

UV-assisted drop casting is an effective technique for shaping ceramic beads; however, venting ceramic suspensions remains a critical factor in achieving well-densified structures. This study investigates optimal venting strategies for manufacturing zirconia beads. Four systems were evaluated, differing in the presence of an anti-foaming agent and additional vacuum venting. The viscosity of the suspensions was studied, and then ceramic beads were obtained by the UV-assisted drop casting method. The sintered beads were then analyzed for their sphericity, size distribution, Vickers hardness, fracture toughness and cross-sectional porosity. In addition, the microstructure of the series that was found to be the best was analyzed in detail. As a result of the study, a mixing and venting procedure was selected that minimizes defects and produces zirconia beads with good mechanical properties and uniform morphology.

I. Mikulionok

Basic data on the properties and volume of municipal (urban) sewage sludge (MSS) formation in the metropolitan region of Ukraine, which is a product of urban sewage treatment, are presented. The analysis of the current state of the ways of MSS management makes it possible to distinguish the following main directions: physical-mechanical, physical-chemical, biological and combined methods of handling it. MSS and its processing products (primarily biocoal (biochar, hydrochar), obtained as a result of incineration, pyrolysis, gasification, or hydrothermal carbonization) are used both individually and in combination with other substances in agriculture (fertilizers; chemical soil melioration); earthworks (reinforcement of weak and expansive soils, use as tamponage compositions, arrangement of embankments, leveling of terrain); road construction (bitumen, asphalt and asphalt concrete mixtures); building materials (cement clinker, cement, concrete, building solutions, bricks, building blocks, artificial stone, glass, glass ceramics, building ceramics, expanded clay (ceramsite), aggregate); protective coatings and materials (paints, shotcrete, thermal insulation materials); sorbents, catalysts and their carriers; compressed fuel; other materials (pigments, electrodes of electric current chemical sources, materials for storing certain substances, coagulants, inoculants, zeolites, glass fibres); in chemical-thermal and biological processes with the production of ash, biochar, pyrolysis liquid and synthesis gas for use as fuel, raw materials and means of other purposes. Currently, the most expedient methods of disposal are the direct use of MSS or its processing products in agriculture and forestry, the building materials industry, as well as in the fuel and energy sector. It should be noted that due to the unpredictable qualitative and quantitative composition of MSS, there are no single recommendations for its effective disposal; however, existing and promising technologies for processing MSS or their analogues make it possible to choose and combine various methods and means under certain conditions. Bibl. 141, Fig. 2.

Dr. Suraju Adesina Adepoju, O. Ojo, O. Olaniyan et al.

This study investigates claystone samples from the northern Bida Basin, northcentral Nigeria, using sedimentological analysis, bulk geochemical techniques (X-ray fluorescence and inductively coupled plasma mass spectrometry), and statistical methods. The research aims to assess the resource potential of the claystone by analyzing mineralogical compositions, weathering indices, and reconstructing depositional environments with emphasis on economic implications. Sedimentological studies identified two sub-facies; the laminated and massive claystones that ranges in color from white, stained-white, and brown to grey, interpreted as suspension-settled deposits of flocculated clay-sized particles within overbank fines of a floodplain. Geochemical analysis of 10 samples from five locations revealed significant SiO2(47.58–78.58%), Al2O3 (12.17–34.35%), and Fe2O3 (0.63–7.11%) contents. Comparison with published values suggests suitability for ceramics and paint production, especially after wet-sieving. Statistical visualization highlighted SiO2 and Al2O3 as dominant oxides. Factor analysis grouped the geochemical data into: (i) F1-F2 (eigenvalues > 1.0), indicating major influence of SiO2 and Al2O3 ; and (ii) F3-F5 (eigenvalues < 1.0), showing minor contributions. Ratios like Ni/Co (1.14–4.00), Cu/Zn (0.42–4.35), U/Th (0.11–0.87), V/Cr (0.04–2.15), and V/(V+Ni) (0.73–0.95) indicate oxic paleodepositional conditions. Provenance indicators such as Al2O3/TiO2 (6.77–20.84), Th/Sc (0.60–4.26), La/Sc (1.59–12.66), and chondrite-normalized REE patterns suggest a source from acidic/silicic igneous rocks. High CIA (88.94–99.49), CIW (96.72–99.94), and PIA (80.40–99.03) values indicate intense weathering in the source area, reflecting non-in-situ clay types. In conclusion, the northern Bida Basin claystones show strong potential as raw materials for ceramics, paint, and brick-making industries.

Caterina Sgarlata, Lincy Varghese, Francesco Ferrari et al.

The ceramics industry has consistently applied circular economy principles by efficiently reusing and recovering raw materials in the production process. Incorporating secondary raw materials, such as production scraps and recycled materials, reduces costs and improves sustainability. In the ceramics sector, raw materials like feldspars can be substituted with secondary raw materials from other production processes, particularly glass-based ones. This study selected waste glass, such as bottle glass or glass fiber processing scraps, to investigate its performance in a porcelain stoneware slab mixture. The behavior of this mixture was compared to a traditional porcelain stoneware mixture and a mixture containing a glass-ceramic frit, which exhibits significantly different behavior from waste glass. The study involved a comprehensive characterization of the fired samples, with a specific focus on addressing pyroplastic deformation—an issue that occurs in large slabs during the firing process. Although pyroplastic deformation has been extensively studied in the past using various waste glasses, this research work uniquely employed waste glass fiber and glass-ceramic material to mitigate pyroplastic deformation compared to the more commonly studied waste soda–lime glass. The pyroplastic deformation tests were conducted using an instrument from Expert Lab Service-MDF.

Ge Li, Astrid S. de Wijn

Quick clay is a highly sensitive soil that transforms rapidly from solid to liquid under minor stress, as a result of long-term salt leaching that drastically reduces shear strength. Stabilizing it is both costly and carbon-intensive, significantly impacting construction emissions in regions like Norway. Developing greener stabilization methods is challenging due to limited understanding of the weakening mechanisms and the specific roles of different salts. In this study, we use molecular dynamics (MD) simulations to investigate the sliding behavior of illite platelets, the key component in Norwegian quick clay, and how it is affected by the different ions in the solution surrounding the surface. We examine the impact of monovalent (NaCl, KCl, CsCl) and divalent (MgCl2 and CaCl2) salts on platelet-surface interactions, focusing on the friction enhancement brought by divalent salts and how the electric double layer (EDL) structure mediates frictional behavior. We find that divalent cations sit higher on top of the surface, and lead to an increase in friction, while monovalent cations sit closer to the surface. By providing a detailed analysis of these interactions, the study offers a novel framework for understanding the role of salts in clay mechanics and highlights opportunities to design environmentally friendly stabilizers as alternatives to traditional lime and cement.

Ashutosh Pandey, Justin Jetter, Hanlin Gu et al.

We present a Gaussian process machine learning model to predict the transformation temperature and lattice parameters of ZrO$_2$-based ceramics. Our overall goal is to search for a shape memory ceramic with a reversible transformation and low hysteresis. The identification of a new low hysteresis composition is based on design criteria that have been successful in metal alloys: (1) $λ_2 = 1$, where $λ_2$ is the middle eigenvalue of the transformation stretch tensor, (2) minimizing the max$|q(f)|$, which measures the deviation from satisfying the cofactor conditions, (3) high transformation temperature, (4) low transformational volume change, and (5) solid solubility. We generate many synthetic compositions, and identify a promising composition, 31.75Zr-37.75Hf-14.5Y-14.5Ta-1.5Er, which closely satisfies all the design criteria based on predictions from machine learning. However, differential thermal analysis reveals a relatively high thermal hysteresis of 137°C for this composition, indicating that the proposed design criteria are not universally applicable to all ZrO$_2$-based ceramics. We also explore reducing tetragonality of the austenite phase by addition of Er$_2$O$_3$. The idea is to tune the lattice parameters of austenite phase towards a cubic structure will increase the number of martensite variants, thus, allowing more flexibility for them to accommodate high strain during transformation. We find the effect of Er$_2$O$_3$ on tetragonality is weak due to limited solubility. We conclude that a more effective dopant is needed to achieve significant tetragonality reduction. Overall, Gaussian process machine learning models are shown to be highly useful for prediction of compositions and lattice parameters, but the discovery of low hysteresis ceramic materials apparently involves other factors not relevant to phase transformations in metals.

Yixuan Feng, Xavier R. Advincula, Hongwei Fang et al.

Montmorillonite, a ubiquitous clay mineral, plays a vital role in geochemical and environmental processes due to its chemically complex edge surfaces. However, the molecular-scale acid-base reactivity of these interfaces remains poorly understood due to the limitations of both experimental resolution and conventional simulations. Here, we employ machine learning potentials with first-principles accuracy to perform nanosecond-scale molecular dynamics simulations of montmorillonite nanoparticles across a range of pH. Our results reveal clear amphoteric behavior: edge sites undergo protonation in acidic environments and deprotonation in basic conditions. Even at neutral pH, spontaneous and directional proton transfer events are common, proceeding via both direct and solvent-mediated pathways. These findings demonstrate that montmorillonite edges are not static arrays of hydroxyl groups but dynamic, proton-conducting networks whose reactivity is modulated by local structure and solution conditions. This work offers a molecular-level framework for understanding proton transport and buffering in clay-water systems, with broad implications for catalysis, ion exchange, and environmental remediation.

Wang Yuxin, Hu Weiwei, Kong Yazhou et al.

Oxide all-solid-state lithium batteries (ASSLBs) are promising candidates for next-generation energy storage due to their high energy density and enhanced safety. However, their commercial application is still hindered by the relatively low conductivity of solid electrolytes. To address this issue, a high-entropy strategy was employed to improve the conductivity of Li0.25La0.25NbO3 (LLNO). A series of entropy-stabilized solid electrolyte ceramics was synthesized via a conventional solid-state reaction method by co-doping five distinct cations (Ta5+, Hf4+, Zr4+, Ti4+, W6+) at the B-site of LLNO. XRD and SEM characterizations confirmed the formation of a perovskite structure in all synthesized samples, including the pristine LLNO, Li0.25La0.25Nb0.9(Ta0.02Hf0.02Zr0.02Ti0.02W0.02)O3 (LLNO-1), Li0.25La0.25Nb0.8(Ta0.04Hf0.04Zr0.04Ti0.04W0.04)O3 (LLNO-2) and Li0.25La0.25Nb0.7(Ta0.06Hf0.06Zr0.06Ti0.06W0.06)O3 (LLNO-3). AC-impedance and DCpolarization measurements demonstrated that the optimized composition of the sample LLNO-2 exhibited a conductivity of 4.68 × 10−6 S/cm and electronic conductivity of 5.30 × 10−8 S/cm with a low activation energy of 0.206 eV, representing a fourfold improvement over the pristine LLNO (conductivity 1.17 × 10−6 S/cm). Although the LLNO-3 ceramics showed the highest conductivity of 6.44 × 10−6 S/cm, it was associated with high activation energy of 0.218 eV and electronic conductivity of 1.28 × 10−7 S/cm. This work demonstrates that high-entropy strategy is a promising for enhancing the conductivity of perovskite-type solid electrolytes for ASSLBs.

S. Ivanov, I. Kovalev, Th. Rehren

Apart from palatial and military archaeological contexts, the Kom Tuman sector of ancient Memphis features an industrial area formed by several high-temperature production and processing workshops of different specializations, operating from the Late period (ca. 664 BCE–ca. 332 BCE) to Hellenistic and Roman times. The study of crucible fragments from these workshops identified a range of coexisting activities, including glass working and metalworking, as well as the primary production of Egyptian blue pigment. This paper provides evidence for these high-temperature industries, discussing both their respective produce and the technical ceramics employed. Analysis of the latter showed that craftspeople in Kom Tuman deliberately selected different types of clay to better fit the requirement of high-temperature production. Both glass and Egyptian blue industries employed crucibles made of calcareous fabric with an external Nile silt coating, while metallurgical activities relied on the use of Nile silt fabric only. Evidence for pottery production is conspicuously absent from these workshops, while evidence for local faience production is very limited.

Stalin Sundara Dhas, Kalaichelvan Kani

Plasma-assisted physical vapour deposition of titanium over an alumina surface, brazed with an aluminium alloy substrate using Al4047 filler, was conducted in a vacuum ranging from 1 × 10−3 to 10−5 mbar. Microstructure characterization, specifically focusing on the Al2O3-Ti coating interface, aims to explain what mechanism underlies the secure bonding of ceramics to metal and how vapour deposition and vacuum atmosphere play a crucial role in achieving this feasibility. Titanium enhanced the wetting characteristics of the alumina surface through chemical reactions. The TiO2 and Ti3Al reaction compounds were identified at the interface. The Ti-rich phase adjacent to the Al2O3 substrate becomes increasingly discontinuous with brazing time. At the Al2O3-Ti interface, a reaction layer of 0.5-1 μm thickness was observed at a brazing temperature of 582 °C held for 40min. In demonstrating defect-free, solidly packed joints, the proposed additive manufacturing approach affirms its suitability for fabricating Al2O3-Al composites at lower joining temperatures, based on the effect of titanium on interfacial bonding characteristics.

Cao Yu, Li Yueming, Li Kai et al.

SiC-ZrC composite powders were synthesized in situ in a high-temperature tubular resistance furnace under an Ar gas atmosphere by carbothermic reduction using SiC, ZrO2 and graphite as starting materials. The effects of reaction temperature, Si/Zr ratio, and graphite dosage on the phase composition, mass loss rate and microstructure of the synthesized products were examined. The synthesized powders were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The results indicate that the increase of the graphite content in the precursor mixture enhances the contact area between ZrO2 and C particles, thereby facilitating the synthesis reaction. When the Si/Zr molar ratio was 7:3 and graphite excess was 10%, SiC-ZrC composite powder with high purity was obtained by holding at 1600°C for 1.5 h. The powder consists mainly of short rod-like particles, quasispherical particles, flaky particles (with an average size of 50-200 nm) and whisker-like substances with a diameter of approximately 50 nm. The SiC and ZrC particles are intact, exhibit good crystallinity and have well-defined grain boundaries.

E. Knapik, Grzegorz Rotko, Marta Marszałek

In recent years there has been a significant increase in the demand for lithium all over the world. Lithium is widely used primarily in the production of batteries for electric vehicles and portable electronic devices, and in many other industries such as production of aluminum, ceramics, glass, polymers, greases, and pharmaceuticals. In order to maintain the balance between supply and demand for lithium on the global market, it is essential to search for alternative sources of this element. Therefore, efforts are being made to obtain lithium from unconventional sources, an example of which is the recovery of lithium from oilfield brines. This article provides an up-to-date review of the literature in this particular field based on data from different sources (scientific literature databases, patent databases, company websites and industrial online newspapers). The current achievements and future perspectives for the lithium recovery from brines generated during oil and gas extraction were critically reviewed. An emphasis was placed on chemistry of lithium-contained oilfield brines, technologies (both pretreatment and direct lithium extraction) suitable for lithium recovery and industrial results obtained from pilot trials.

Maham Hussain, F. Uddin, Nadeem Raza et al.

ABSTRACT Lithium extraction from natural resources is an accelerating field of research owing to its growing demand in the medical, nuclear, battery, and air conditioning industries. Lithium compounds are used in various industries, including ceramics, glass, lubricant gases, rocket propellant, and aluminum production. The extraction of lithium from seawater via adsorption using AlCl3.6 H2O as an adsorbent is investigated in this study. The effect of process parameters such as pH, temperature, contact time, the molar ratio ([Al3+]/[Li+]), and stirring rate on process efficiency is investigated and optimized. The response surface methodology (RSM) is used to investigate the effects of operating parameters and choose the optimal configuration. A standard synthetic solution containing 50 ppm lithium is prepared and experimented with facilitating comprehension of the procedure. The adsorption efficiency of a synthetic solution is 88% at optimized values, while that of seawater is 78.5%. Seawater has a lower efficiency because it contains ions such as Mg2+, Ca2+, K+, and Na+ that compete for active points/sites during adsorption with lithium ions (Li+). GRAPHICAL ABSTRACT

Sheng-Li Chen, Hai-Sui Yu, Younane N. Abousleiman et al.

A theoretical model describing the one-dimensional large strain consolidation of the modified Cam Clay soil is presented in this paper. The model is based on the Lagrangian formulation, and is capable of featuring the variability of soil compressibility (inherently so due to the direct incorporation of the specific Cam Clay plasticity model) and permeability, as well as the impact of overconsolidation ratio. The derivation starts from the establishment of the incremental stress-strain relations for both purely elastic and elastoplastic deformations under one-dimensional compression condition, and thereafter the coefficients of compressibility/volume change that are essential to the consolidation analysis. The governing partial differential equation is then neatly deduced in conjunction with the continuity and equilibrium conditions for the soil, with the vertical effective stress being the privileged unknown to be solved for. Subsequently, semi-analytical solution to the developed rigorous poroelastoplastic large strain consolidation model is obtained and verified with the ABAQUS finite element numerical results. Parametric analyses are finally provided to investigate in detail the influences of the soil overconsolidation ratio, large strain configuration, and the variability of the soil permeability on the calculated one-dimensional consolidation response.

Vasily Artemov, Svetlana Babiy, Yunfei Teng et al.

Water confined to channels one nanometer thick exhibits electrochemical behavior distinct from bulk water, including enhanced protonic conductivity and large dielectric anisotropy. Here, we exploit these characteristics to design a scalable electrochemical energy-storage system ("blue capacitor") constructed entirely from naturally abundant materials. By assembling layered clays and conductive graphene, we produce 1-nm-thick channels in which confined water acts as the sole electrolyte. We systematically study different clay types, the electrode composition, and separator thickness using complementary physicochemical and electrochemical techniques. The device operates stably up to 1.6 V, achieves specific capacitances of up to 40 F/g, nearly 100% coulombic efficiency, and stable performance over more than 60,000 charge-discharge cycles. Structural and dynamic analyses validate the device architecture, water purity, and proton transport in the nanopores. These results demonstrate that nanoconfined water can function as an electrolyte in a macroscopic electrochemical device, providing a platform for exploring sustainable aqueous energy-storage systems.

Yiwen Liu, Hong Meng, Zijie Zhu et al.

The mechanical and thermal performance of high-entropy ceramics are critical to their use in extreme conditions. However, the vast composition space of high-entropy ceramic significantly hinders their development with desired mechanical and thermal properties. Herein, taking high-entropy carbides (HECs) as the model, we show the efficiency and effectiveness of exploring the mechanical and thermal properties via machine-learning-potential-based molecular dynamics (MD). Specifically, a general neuroevolution potential (NEP) with broad compositional applicability for HECs of ten transition metal elements from group IIIB-VIB is efficiently constructed from the small dataset comprising unary and binary carbides with an equal amount of ergodic chemical compositions. Based on this well-established NEP, MD simulations on mechanical and thermal properties of different HECs have shown good agreement with the results of first-principles calculations and experimental measurements, validating the accuracy, generalization, and reliability of using the developed general NEP in investigating mechanical and thermal performance of HECs. Our work provides an efficient solution to accelerate the search for high-entropy ceramics with desirable mechanical and thermal properties.

Yuxuan Wang, Guoqiang Lan, Jun Song

Medium and high entropy ceramics, with their distinctive disordered structures, exhibit ultra-low thermal conductivity and high temperature stability. These properties make them strong contenders for next generation thermal barrier coating (TBC) materials. However, predicting their thermal conductivity has been challenging, primarily due to their unique phonon scattering mechanisms. Apart from the conventional phonon-phonon scattering mechanism, the phonon-disorder scattering, comprising both mass and force constant disorder, are also expected to make significant contribution in determining the thermal conductivity of medium and high entropy ceramics. However, it remains challenging to quantify the phonon-disorder contribution, particular in the aspect of force constant disorder. Here we demonstrated a relationship between the lattice disorder, a quantity more readily calculable, with force constant disorder, rendering it possible to substitute the force constant disorder by lattice disorder. Based on this relationship and drawing inspiration from Klement's equation of static imperfection, we have developed a model that quantitatively assesses the connection between disorder and thermal conductivity. Applying our model to the medium/high entropy rocksalt and pyrochlore oxides as representatives, we found good alignment between the theoretical predictions and experimental measurements of thermal conductivities, confirming the validity of our model. The model developed offers a critical predictive tool for rapid screening of TBC materials based on medium and high entropy ceramics.

Raphael Thiraux, Alexander D. Dupuy, Kate M. Ainger et al.

Mechanical characterization of ceramics is challenging, as the statistical nature of their strength requires numerous specimens to extract reliable distribution parameters. Here, we first propose a high-throughput testing procedure that allows extraction of statistical information on the strength of ceramic materials. We process large numbers of bending specimens from low volumes of material via Direct Ink Writing (DIW), and rapidly characterize them to extract Weibull parameters for bending strength. After investigating five ceramics and downselecting two formulations, we develop a multi-scale procedure to explore the impact of printing-induced defects on the strength distribution of DIW-processed ceramics. Finally, we demonstrate that a judicious choice of the printing strategy produces porous architected structures which can significantly exceed the strength of fully dense DIW-produced monolithic materials. While the results are presented on DIW-processed alumina-based ceramics, the approach is versatile and can provide rapid statistical data on the strength of many ceramic materials.

Hicham Ait Laasri, Eliane Bsaibess, Fabian Delorme et al.

$BaWO_{4}$, $Ce_{2/3}\square_{1/3}WO_{4}$ and $La_{2/3}\square_{1/3}WO_{4}$ polycrystalline ceramics were synthesized by conventional solid-state reaction route. The effect of cation-deficiency on the crystallographic structure, microstructure and thermal properties of these scheelite-type compounds were investigated. X-ray diffraction was used to identify the single-phase scheelite structure of the studied ceramics. Scanning Electron Microscopy technique has revealed a homogenous and dense microstructure with a few micro-cracks. The thermal conductivity of $BaWO_{4}$ scheelite decreases from $1.3\pm0.2$ to $1.0\pm0.1 W m^{-1} K^{-1}$ in the range 373 K - 673 K. The cation-deficient scheelites $Ce_{2/3}\square_{1/3}WO_{4}$ and $La_{2/3}\square_{1/3}WO_{4}$ ceramics display an ultra-low thermal conductivity of $0.3\pm0.04 W m^{-1} K^{-1}$ and $0.2\pm0.03 W m^{-1} K^{-1}$ at 673 K, respectively. These materials exhibit among the lowest known values of thermal conductivity in crystalline oxides, in this temperature range. Therefore, they appear as very attractive for thermal barrier coating and thermoelectric applications.

Michael I. Ojovan, Sergey V. Yudintsev

We briefly overview the utilisation of glasses, ceramics and glass crystalline materials (GCMs) composed of both vitreous and crystalline phases focusing on nuclear waste immobilisation and potential use of some advanced waste forms for incorporation of the rare earth elements (REE) and minor actinide (MA: Am, Cm) fraction of high-level waste (HLW).