The firing of ceramic ware in chamber furnaces is a transient multiphysical process,including turbulence combustion and fluid flow in the gas space,convective and radiation heat transfer from the flue gases to the fur...The firing of ceramic ware in chamber furnaces is a transient multiphysical process,including turbulence combustion and fluid flow in the gas space,convective and radiation heat transfer from the flue gases to the furnace walls and ceramic ware,surface to surface radiation between the solid surfaces and conduction heat transfer in combination with endothermic or exothermic processes in the ceramic body.Models and conceptions for numerical analysis of that conjugate heat transfer(CHT)in such thermal aggregates are developed.They are validated on the base of information,obtained by in situ measurements at a furnace for firing of technical ceramic.Non-uniform thermal and fluid flow fields in the furnace space that cause problems in the surrounding walls and wastes at the ceramic ware are ascertained in it.An impossibility to improve the furnace operation at the existing construction and combustion installation is established.A variant for reconstruction of the furnace is investigated numerically.It includes changes of the number,power and topology of the burners and different arrangement of the ceramic ware in the furnace space.Uniform temperature fields and reduction of the specific fuel consumption at the suggested configuration of the thermal aggregate are established.展开更多
PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula...PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.展开更多
Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SE...Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO<sub>2</sub> (~57% - 66%), Al<sub>2</sub>O<sub>3 </sub>(~13% - 15%), Fe<sub>2</sub>O<sub>3</sub> (~6% - 10%), TiO<sub>2</sub> (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K<sub>2</sub>O, CaO, Na<sub>2</sub>O). Negligible and trace of MgO (~1%) and P<sub>2</sub>O<sub>5</sub> was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application.展开更多
Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited r...Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited research on the deformation and damage process of zirconia ceramics. This article analyzes the acoustic emission characteristics of each stage of ceramic damage from the perspective of acoustic emission, and explores its deformation process characteristics from multiple perspectives such as time domain, frequency, and EWT modal analysis. It is concluded that zirconia ceramics exhibit higher brittleness and acoustic emission strength than alumina ceramics, and when approaching the fracture, it tends to generate lower frequency acoustic emission signals.展开更多
This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & sil...This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.展开更多
This article is investigating analysis and chemical composition of ceramic pegmatite minerals obtained from the Terek deposit in Toktogul district of Kyrgyzstan. Several methods such as mineralogical studies, magnetic...This article is investigating analysis and chemical composition of ceramic pegmatite minerals obtained from the Terek deposit in Toktogul district of Kyrgyzstan. Several methods such as mineralogical studies, magnetic and gravitational enrichments, silicate and chemical analyses of ceramic pegmatite minerals, quartz-feldspathic concentrate and sludge removal have been performed for determination of pegmatite mineral applicability for production of porcelain and earthenware.展开更多
Using steel slag as a main raw material of ceramics is considered as a high value-added way. However, the relationship among the initial composition, ceramic microstructure, and macroscopic properties requires further...Using steel slag as a main raw material of ceramics is considered as a high value-added way. However, the relationship among the initial composition, ceramic microstructure, and macroscopic properties requires further study. In this paper, a series of ceramics with different slag ratios (0-70wt%) were designed, and the software FACTsage was introduced to simulate the formation of crystalline phases. The simulation results indicate that mullite is generated but drastically reduced at the slag ratios of 0-25wt%, and anorthite is the dominant crystalline phase in the slag content of 25wt%-45wt%. When the slag ratio is above 45wt%, pyroxene is generated more than anorthite. This is because increasing magnesium can promote the formation of pyroxene. Then, the formula with a slag content of 40wt% was selected and optimized. X-ray diffraction results were good consistent with the simulation results. Finally, the water absorption and bending strength of optimized samples were measured.展开更多
Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The resu...Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The results showed that oxides resulted in numerous preliminary spinels in the glass matrix.FeO,ZnO,and Fe_(2)O_(3)influenced the formation of spinel,while FeO simplified the glass network.FeO and ZnO promoted bulk crystallisation of the parent glass.After adding oxides,the grains of augite phase were refined,and the relative quantities of augite crystal planes were also influenced.All samples displayed good mechanical properties and chemical stability.The 2wt%ZnO-doping sample displayed the maximum flexural strength(170.3 MPa).Chromium leaching amount values of all the samples were less than the national standard(1.5 mg/L),confirming the safety of the materials.In conclusion,an appropriate amount of zinc-containing raw material is beneficial for the preparation of augite-based glass ceramics.展开更多
In an effort to explore the use of natural resources, stoneware ceramics have been made using iron sand as a filler to replace quartz Kalimantan. The results showed that iron sand can be well used in making stoneware ...In an effort to explore the use of natural resources, stoneware ceramics have been made using iron sand as a filler to replace quartz Kalimantan. The results showed that iron sand can be well used in making stoneware ceramics. This is shown by the measurement of water absorption which is less than 5% and has compressive strength slightly smaller compared to stoneware ceramics made with quartz as a filler.展开更多
Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates(CCBIPs),distribution characteristics of ceramic fragments within a specific size ...Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates(CCBIPs),distribution characteristics of ceramic fragments within a specific size range were analyzed for different Armor Piercing Incendiary(API)and shot times.To quantitatively evaluate the effect of energy absorption for ceramic plates,a model of energy absorption during penetration for CCBIPs was established based on statistics of the size distribution of ceramic fragments(SDCF).Variation in the SDCF and its influence on energy absorption for CCBIPs were investigated.The results indicate that the distribution feature of ceramic fragments in the range of 0.25-2.25 mm is Gaussian distribution.Compared with Type 56 of API(56-API),ceramic fragments formed by 53-API with higher kinetic energy possess more quantity and more concentrated distribution,whose average equivalence size decreases by 6.5%,corresponding to increasing by 83.9%of estimated energy absorption.Besides,the ability of CCBIPs to resist the third shot is significantly weakened,whose estimated energy absorption decreases by 58.8%compared with the first shot.More concentrated distribution and fewer fragments are formed after the third shot,the average equivalence size of ceramic fragments increases by 6.9%,which may attribute to the micro-cracks induced by the previous two shots.展开更多
As a part of the framework of the development of ceramic products, scientific research continues this idea that clays are essential vehicles for local development in Africa;and therefore they deserve to be made profit...As a part of the framework of the development of ceramic products, scientific research continues this idea that clays are essential vehicles for local development in Africa;and therefore they deserve to be made profitable. This scientific work has the advantage of providing a solution to the housing of the Sahel area. On the other hand, this study can effectively serve as the basis of data in the formulation of ceramics from clay Maroua, in the region of the Far North Cameroon, for a large-scale industrial operation. Thus, two samples of materials respectively KO1 and IP2 have been the subject of a preliminary chemical and mineralogical size rheological study. Once formed, the tubes containing the KO1 and PI2 materials have undergone heat treatment at successive temperatures of 900°C, 1000°C and 1100°C. The baked products obtained have also been the subject of a study of resonance, coloring density, loss on ignition, water absorption, linear shrinkage, porosity and mechanical compression.展开更多
Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,c...Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.展开更多
A solid-state sodium metal battery has cut a striking figure in next-generation large-scale energy storage technology on account of high safety,high energy density,and low cost.Nevertheless,the large interfacial resis...A solid-state sodium metal battery has cut a striking figure in next-generation large-scale energy storage technology on account of high safety,high energy density,and low cost.Nevertheless,the large interfacial resistance and sodium dendrite growth originating from the poor interface contact seriously hinder its practical application.Herein,a modified ultrasound welding was proposed to atomically bond Na anodes and Au-metalized Na_(3)Zr_(2)Si_(2)PO_(12) electrolytes associated with the in situ formation of Na–Au alloy interlayers.Thereupon,intimate Na_(3)Zr_(2)Si_(2)PO_(12)-Au/Na interfaces with a low interfacial resistance(~23Ωcm^(2))and a strong dendrite inhibition ability were constructed.The optimized Na symmetric battery can cycle steadily for more than 900 h at 0.3 mA cm^(-2) under a low overpotential(<50 mV)of Na electroplating/stripping and deliver a high critical current density of 0.8 mAcm^(-2) at room temperature.By incorporating the above interface into the solid-state Na metal battery,taking three-dimensional Na_(3)V_(2)(PO_(4))_(3) as the cathode,the full battery offers a high energy density of 291 Wh kg^(-1) at a high power density of 1860Wkg^(-1).A pouch-type solid-state sodium metal full battery based on a ceramic electrolyte was assembled for the first time,and it lit a 3 V LED lamp.Such a strategy of the ultrasound welding metalized solid-state electrolyte/Na interface by engineering the Na-Au interlayer would pave a new pathway to engineer a low-resistance and highly stable interface for high-energy/density solid-state sodium metal batteries.展开更多
Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M...Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.展开更多
In C ?te d’Ivoire, traditional ceramics are widely used in the form of pottery. The latter is used to store food, water and cereals. Analyzes (X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ...In C ?te d’Ivoire, traditional ceramics are widely used in the form of pottery. The latter is used to store food, water and cereals. Analyzes (X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM) and analysis thermal gravimetric (ATG)) were carried out to determine the morphology, the chemical, physical and pedological constituents of these raw materials. It appears from this study that the clays used in the Mangoro pottery of Katiola contain silica SiO<sub>2</sub>, alumina Al<sub>2</sub>O<sub>3</sub> and iron oxide Fe<sub>2</sub>O<sub>3</sub> as well as kaolinite, muscovite, smectite and quartz.展开更多
A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,micros...A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,microstructures,and microwave dielectric properties were investigated.The results of x-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that a single phase of MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with a spinel structure was obtained at x≤0.12,whereas the second phase of MgTi_(2)O_(5)appeared when x>0.12.The cell parameters were obtained by XRD refinement.As the x values increased,the unit cell volume kept expanding.This phenomenon could be attributed to the partial substitution of(Li_(1/3)Ti_(2/3))^(3+)for Al^(3+).Results showed that(Li_(1/3)Ti_(2/3))^(3+)doping into MgAl_(2)O_(4)spinel ceramics effectively reduced the sintering temperature and improved the quality factor(Q_f)values.Good microwave dielectric properties were achieved for a sample at x=0.20 sintering at 1500℃in air for 4 h:dielectric constantε_(r)=8.78,temperature coefficient of resonant frequencyτ_(f)=-85 ppm/℃,and Q_(f)=62300 GHz.The Q_(f)value of the x=0.20 sample was about 2 times higher than that of pure MgAl_(2)O_(4)ceramics(31600 GHz).Thus,MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with excellent microwave dielectric properties can be applied to 5G communications.展开更多
Green and sustainable concrete has attracted significant attention from the construction industry and researchers since it was proposed.The ceramic waste materials are often directly buried in the ground or placed in ...Green and sustainable concrete has attracted significant attention from the construction industry and researchers since it was proposed.The ceramic waste materials are often directly buried in the ground or placed in an open dump,and the accumulation of ceramic waste contributes to environmental pollution,which makes the recycling of ceramic waste quite urgent.Owing to the pozzolanic activity,excellent mechanical properties and durability,industrial ceramic waste is considered as a suitable substitute for cement or natural aggregates to fabricate renewable concrete.In this paper,the pozzolanic activity of ceramic waste and the workability,mechanical performance,and durability of ceramic concrete are discussed.In addition,the most recent research results pertaining to ceramic concrete are reviewed.Ground ceramic powder improves the workability,compressive strength,resistance to chloride penetration,and carbonation resistance of concrete to a certain extent.Concrete containing ceramic as the aggregate has a lower mechanical performance than ordinary concrete.However,the resistance to chloride penetration,freeze-thaw resistance,and high-temperature resistance of ceramic concrete are remarkable.Ceramic concrete is environmentally friendly,requires fewer energy resources to manufacture than ordinary concrete,and has excellent engineering properties.However,further research is required for future engineering applications.展开更多
Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatur...Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatures by proton conducting ceramic cell electrolysis(PCCEL).We demonstrate a highperformance steam electrolysis owing to a composite positrode based on BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC1082)and BaZr0.5Ce0.4Y0.1O3-δ(BZCY541).The high reliability of PCCEL is demonstrated for 1680 h at a current density as high as-0.8 A cm^(-2)close to the thermoneutral cell voltage at 600℃.The electrolysis cell showed a specific energy consumption ranging from 54 to 66 kW h kg^(-1)that is comparable to state-of-the-art low temperature electrolysis technologies,while showing hydrogen production rates systematically higher than commercial solid oxide ceramic cells(SOCs).Compared to SOCs,the results verified the higher performances of PCCs at the relevant operating temperatures,due to the lower activation energy for proton transfer comparing with oxygen ion conduction.However,because of the p-type electronic conduction in protonic ceramics,the energy conversion rate of PCCs is relatively lower in steam electrolysis.The faradaic efficiency of the PCC in electrolysis mode can be increased at lower operating temperatures and in endothermic conditions,making PCCEL a technology of choice to valorize high temperature waste heat from industrial processes into hydrogen.To increase the faradaic efficiency by optimizing the materials,the cell design,or the operating strategy is a key challenge to address for future developments of PCCEL in order to achieve even more superior techno-economic merits.展开更多
In this study,the effect of sintering temperature and the addition of kaolin,a sintering agent,on the microscopic,phase,and mechanical properties of ceramics were investigated using secondary aluminum dross(SAD)as the...In this study,the effect of sintering temperature and the addition of kaolin,a sintering agent,on the microscopic,phase,and mechanical properties of ceramics were investigated using secondary aluminum dross(SAD)as the main component in the manufacturing of ceramics.The basic phases of the ceramics were Al_(2)O_(3),MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2)without the addition of kaolin.The diffraction peaks of MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2)kept decreasing while those of Al_(2)O_(3)kept increasing with an increase in temperature.In addition,the increase in temperature promoted the growth of the grains.The grains were uniform in size and regular in distribution,with a shrinkage of 2.2%,porosity of 72.5%,bulk density of 1.076 g/cm^(3),and compressive strength of 1.12 MPa.When the sintering temperature was 1450°C,the basic phases of the ceramic after the addition of kaolin were Al_(2)O_(3),MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2).With the increase of kaolin,the diffraction peaks of NaAl_(11)O_(17)and SiO_(2)decreased until they disappeared,while the diffraction peaks of Al_(2)O_(3)increased significantly.When kaolin was added at 30 wt.%,the ceramics obtained had shrinkage of 18%,a porosity of 47.26%,a bulk density of 1.965 g/cm^(3),and compressive strength of 31.9 MPa.Cracks existed inside the ceramics without the addition of kaolin,while the addition of kaolin significantly changed this defect.It is shown that SAD can obtain porous ceramics with good properties at a sintering temperature of 1450°C and a kaolin addition of 30 wt.%.展开更多
Mullite thermal storage ceramics were prepared by low-cost calcined bauxite and kaolin.The phase composition,microstructure,high temperature resistance and thermophysical properties were characterized by modern testin...Mullite thermal storage ceramics were prepared by low-cost calcined bauxite and kaolin.The phase composition,microstructure,high temperature resistance and thermophysical properties were characterized by modern testing techniques.The experimental results indicate that sample A3(bauxite/kaolin ratio of 5:5)sintered at 1620℃has the optimum comprehensive properties,with bulk density of 2.83 g·cm^(-3)and bending strength of 155.44 MPa.After 30 thermal shocks(1000℃-room temperature,air cooling),the bending strength of sample A3 increases to 166.15 MPa with an enhancement rate of 6.89%,the corresponding thermal conductivity and specific heat capacity are 3.54 W·(m·K)^(-1)and 1.39 kJ·(kg·K)^(-1)at 800℃,and the thermal storage density is 1096 kJ·kg^(-1)(25-800 mullite ceramics;sintering properties;high-temperature thermal storage;thermal shock resistance).Mullite forms a dense and continuous interlaced network microstructure,which endows the samples high thermal storage density and high bending strength,but the decrease of bauxite/kaolin ratio leads to the decrease of mullite content,which reduces the properties of the samples.展开更多
文摘The firing of ceramic ware in chamber furnaces is a transient multiphysical process,including turbulence combustion and fluid flow in the gas space,convective and radiation heat transfer from the flue gases to the furnace walls and ceramic ware,surface to surface radiation between the solid surfaces and conduction heat transfer in combination with endothermic or exothermic processes in the ceramic body.Models and conceptions for numerical analysis of that conjugate heat transfer(CHT)in such thermal aggregates are developed.They are validated on the base of information,obtained by in situ measurements at a furnace for firing of technical ceramic.Non-uniform thermal and fluid flow fields in the furnace space that cause problems in the surrounding walls and wastes at the ceramic ware are ascertained in it.An impossibility to improve the furnace operation at the existing construction and combustion installation is established.A variant for reconstruction of the furnace is investigated numerically.It includes changes of the number,power and topology of the burners and different arrangement of the ceramic ware in the furnace space.Uniform temperature fields and reduction of the specific fuel consumption at the suggested configuration of the thermal aggregate are established.
基金supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF2022R1C1C1007619, NRF-2021M3H4A1A01002921, NRF2021M3I3A1084292)supported by the KIST Institutional Program (Project No. 2E32592-23-069)。
文摘PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.
文摘Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO<sub>2</sub> (~57% - 66%), Al<sub>2</sub>O<sub>3 </sub>(~13% - 15%), Fe<sub>2</sub>O<sub>3</sub> (~6% - 10%), TiO<sub>2</sub> (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K<sub>2</sub>O, CaO, Na<sub>2</sub>O). Negligible and trace of MgO (~1%) and P<sub>2</sub>O<sub>5</sub> was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application.
文摘Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited research on the deformation and damage process of zirconia ceramics. This article analyzes the acoustic emission characteristics of each stage of ceramic damage from the perspective of acoustic emission, and explores its deformation process characteristics from multiple perspectives such as time domain, frequency, and EWT modal analysis. It is concluded that zirconia ceramics exhibit higher brittleness and acoustic emission strength than alumina ceramics, and when approaching the fracture, it tends to generate lower frequency acoustic emission signals.
文摘This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.
文摘This article is investigating analysis and chemical composition of ceramic pegmatite minerals obtained from the Terek deposit in Toktogul district of Kyrgyzstan. Several methods such as mineralogical studies, magnetic and gravitational enrichments, silicate and chemical analyses of ceramic pegmatite minerals, quartz-feldspathic concentrate and sludge removal have been performed for determination of pegmatite mineral applicability for production of porcelain and earthenware.
基金financially supported by the National Natural Science Foundation of China (Nos. 51034008 and 51004012)the National High Technology Research and Development Program of China (No. 2011AA06A105)
文摘Using steel slag as a main raw material of ceramics is considered as a high value-added way. However, the relationship among the initial composition, ceramic microstructure, and macroscopic properties requires further study. In this paper, a series of ceramics with different slag ratios (0-70wt%) were designed, and the software FACTsage was introduced to simulate the formation of crystalline phases. The simulation results indicate that mullite is generated but drastically reduced at the slag ratios of 0-25wt%, and anorthite is the dominant crystalline phase in the slag content of 25wt%-45wt%. When the slag ratio is above 45wt%, pyroxene is generated more than anorthite. This is because increasing magnesium can promote the formation of pyroxene. Then, the formula with a slag content of 40wt% was selected and optimized. X-ray diffraction results were good consistent with the simulation results. Finally, the water absorption and bending strength of optimized samples were measured.
基金supported by the National Key R&D Program of China(No.2019YFC1905701)the National Natural Science Foundation of China(Nos.U1960201 and 52204336)the China Postdoctoral Science Foundation(No.2022M710359).
文摘Augite-based glass ceramics were synthesised using ZnO,FeO,and Fe_(2)O_(3)as additives,and the spinel formation,matrix structure,crystallisation thermodynamics,and physicochemical properties were investigated.The results showed that oxides resulted in numerous preliminary spinels in the glass matrix.FeO,ZnO,and Fe_(2)O_(3)influenced the formation of spinel,while FeO simplified the glass network.FeO and ZnO promoted bulk crystallisation of the parent glass.After adding oxides,the grains of augite phase were refined,and the relative quantities of augite crystal planes were also influenced.All samples displayed good mechanical properties and chemical stability.The 2wt%ZnO-doping sample displayed the maximum flexural strength(170.3 MPa).Chromium leaching amount values of all the samples were less than the national standard(1.5 mg/L),confirming the safety of the materials.In conclusion,an appropriate amount of zinc-containing raw material is beneficial for the preparation of augite-based glass ceramics.
文摘In an effort to explore the use of natural resources, stoneware ceramics have been made using iron sand as a filler to replace quartz Kalimantan. The results showed that iron sand can be well used in making stoneware ceramics. This is shown by the measurement of water absorption which is less than 5% and has compressive strength slightly smaller compared to stoneware ceramics made with quartz as a filler.
基金financially supported by the National Key Research&Development Project(2017YFB1103505)the Military Logistics Research Program(XXXC002)of China。
文摘Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates(CCBIPs),distribution characteristics of ceramic fragments within a specific size range were analyzed for different Armor Piercing Incendiary(API)and shot times.To quantitatively evaluate the effect of energy absorption for ceramic plates,a model of energy absorption during penetration for CCBIPs was established based on statistics of the size distribution of ceramic fragments(SDCF).Variation in the SDCF and its influence on energy absorption for CCBIPs were investigated.The results indicate that the distribution feature of ceramic fragments in the range of 0.25-2.25 mm is Gaussian distribution.Compared with Type 56 of API(56-API),ceramic fragments formed by 53-API with higher kinetic energy possess more quantity and more concentrated distribution,whose average equivalence size decreases by 6.5%,corresponding to increasing by 83.9%of estimated energy absorption.Besides,the ability of CCBIPs to resist the third shot is significantly weakened,whose estimated energy absorption decreases by 58.8%compared with the first shot.More concentrated distribution and fewer fragments are formed after the third shot,the average equivalence size of ceramic fragments increases by 6.9%,which may attribute to the micro-cracks induced by the previous two shots.
文摘As a part of the framework of the development of ceramic products, scientific research continues this idea that clays are essential vehicles for local development in Africa;and therefore they deserve to be made profitable. This scientific work has the advantage of providing a solution to the housing of the Sahel area. On the other hand, this study can effectively serve as the basis of data in the formulation of ceramics from clay Maroua, in the region of the Far North Cameroon, for a large-scale industrial operation. Thus, two samples of materials respectively KO1 and IP2 have been the subject of a preliminary chemical and mineralogical size rheological study. Once formed, the tubes containing the KO1 and PI2 materials have undergone heat treatment at successive temperatures of 900°C, 1000°C and 1100°C. The baked products obtained have also been the subject of a study of resonance, coloring density, loss on ignition, water absorption, linear shrinkage, porosity and mechanical compression.
基金support by the National Natural Science Foundation of China(51802269,21773138)Fundamental Research Funds for the Central Universities(XDJK2019AA002)+1 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2018027)the innovation platform for academicians of Hainan province.
文摘Using porous carbon hosts in cathodes of Li-S cells can disperse S actives and offset their poor electrical conductivity.However,such reservoirs would in turn absorb excess electrolyte solvents to S-unfilled regions,causing the electrolyte overconsumption,specific energy decline,and even safety hazards for battery devices.To build better cathodes,we propose to substitute carbons by In-doped SnO_(2)(ITO)nano ceramics that own three-in-one functionalities:1)using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio(~3%)in cathodes,elevating the electrode tap density and averting the electrolyte overuse;2)polar ITO nanoclusters can serve as robust anchors toward Li polysulfide(LiPS)by electrostatic adsorption or chemical bond interactions;3)they offer catalysis centers for liquid–solid phase conversions of S-based actives.Also,such ceramics are intrinsically nonflammable,preventing S cathodes away from thermal runaway or explosion.These merits entail our configured cathodes with high tap density(1.54 g cm^(−3)),less electrolyte usage,good security for flame retardance,and decent Li-storage behaviors.With lean and LiNO_(3)-free electrolyte,packed full cells exhibit excellent redox kinetics,suppressed LiPS shuttling,and excellent cyclability.This may trigger great research enthusiasm in rational design of low-carbon and safer S cathodes.
基金Scientific Developing Foundation of Tianjin Education Commission,Grant/Award Number:2018ZD09National Natural Science Foundation of China,Grant/Award Numbers:51777138,52202282。
文摘A solid-state sodium metal battery has cut a striking figure in next-generation large-scale energy storage technology on account of high safety,high energy density,and low cost.Nevertheless,the large interfacial resistance and sodium dendrite growth originating from the poor interface contact seriously hinder its practical application.Herein,a modified ultrasound welding was proposed to atomically bond Na anodes and Au-metalized Na_(3)Zr_(2)Si_(2)PO_(12) electrolytes associated with the in situ formation of Na–Au alloy interlayers.Thereupon,intimate Na_(3)Zr_(2)Si_(2)PO_(12)-Au/Na interfaces with a low interfacial resistance(~23Ωcm^(2))and a strong dendrite inhibition ability were constructed.The optimized Na symmetric battery can cycle steadily for more than 900 h at 0.3 mA cm^(-2) under a low overpotential(<50 mV)of Na electroplating/stripping and deliver a high critical current density of 0.8 mAcm^(-2) at room temperature.By incorporating the above interface into the solid-state Na metal battery,taking three-dimensional Na_(3)V_(2)(PO_(4))_(3) as the cathode,the full battery offers a high energy density of 291 Wh kg^(-1) at a high power density of 1860Wkg^(-1).A pouch-type solid-state sodium metal full battery based on a ceramic electrolyte was assembled for the first time,and it lit a 3 V LED lamp.Such a strategy of the ultrasound welding metalized solid-state electrolyte/Na interface by engineering the Na-Au interlayer would pave a new pathway to engineer a low-resistance and highly stable interface for high-energy/density solid-state sodium metal batteries.
基金Project supported by the Doctoral Research Fund of Southwest University of Science and Technology(Grant No.20zx7104)the Sichuan Science and Technology Program(Grant No.2020ZYD055)the National Natural Science Foundation of China(Grant Nos.11905206 and 12075194)。
文摘Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.
文摘In C ?te d’Ivoire, traditional ceramics are widely used in the form of pottery. The latter is used to store food, water and cereals. Analyzes (X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM) and analysis thermal gravimetric (ATG)) were carried out to determine the morphology, the chemical, physical and pedological constituents of these raw materials. It appears from this study that the clays used in the Mangoro pottery of Katiola contain silica SiO<sub>2</sub>, alumina Al<sub>2</sub>O<sub>3</sub> and iron oxide Fe<sub>2</sub>O<sub>3</sub> as well as kaolinite, muscovite, smectite and quartz.
基金the Chengdu University of Technology(Grant No.KYQD201907728)。
文摘A series of nominal compositions MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)(x=0,0.04,0.08,0.12,0.16,and 0.20)ceramics were successfully prepared via the conventional solid-state reaction route.The phase compositions,microstructures,and microwave dielectric properties were investigated.The results of x-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that a single phase of MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with a spinel structure was obtained at x≤0.12,whereas the second phase of MgTi_(2)O_(5)appeared when x>0.12.The cell parameters were obtained by XRD refinement.As the x values increased,the unit cell volume kept expanding.This phenomenon could be attributed to the partial substitution of(Li_(1/3)Ti_(2/3))^(3+)for Al^(3+).Results showed that(Li_(1/3)Ti_(2/3))^(3+)doping into MgAl_(2)O_(4)spinel ceramics effectively reduced the sintering temperature and improved the quality factor(Q_f)values.Good microwave dielectric properties were achieved for a sample at x=0.20 sintering at 1500℃in air for 4 h:dielectric constantε_(r)=8.78,temperature coefficient of resonant frequencyτ_(f)=-85 ppm/℃,and Q_(f)=62300 GHz.The Q_(f)value of the x=0.20 sample was about 2 times higher than that of pure MgAl_(2)O_(4)ceramics(31600 GHz).Thus,MgAl_(2-x)(Li_(1/3)Ti_(2/3))_(x)O_(4)ceramics with excellent microwave dielectric properties can be applied to 5G communications.
基金support received from Natural Science Foundation of Henan(Grant No.212300410018)National Natural Science Foundation of China(Grant No.U2040224)+1 种基金Program for Innovative Research Team(in Science and Technology)in University of Henan Province of China(Grant No.20IRTSTHN009)the Research and Develop Project of China Construction Seventh Engineering Division Co.,Ltd.(Grant No.CSCEC7b-2021-Z-11).
文摘Green and sustainable concrete has attracted significant attention from the construction industry and researchers since it was proposed.The ceramic waste materials are often directly buried in the ground or placed in an open dump,and the accumulation of ceramic waste contributes to environmental pollution,which makes the recycling of ceramic waste quite urgent.Owing to the pozzolanic activity,excellent mechanical properties and durability,industrial ceramic waste is considered as a suitable substitute for cement or natural aggregates to fabricate renewable concrete.In this paper,the pozzolanic activity of ceramic waste and the workability,mechanical performance,and durability of ceramic concrete are discussed.In addition,the most recent research results pertaining to ceramic concrete are reviewed.Ground ceramic powder improves the workability,compressive strength,resistance to chloride penetration,and carbonation resistance of concrete to a certain extent.Concrete containing ceramic as the aggregate has a lower mechanical performance than ordinary concrete.However,the resistance to chloride penetration,freeze-thaw resistance,and high-temperature resistance of ceramic concrete are remarkable.Ceramic concrete is environmentally friendly,requires fewer energy resources to manufacture than ordinary concrete,and has excellent engineering properties.However,further research is required for future engineering applications.
基金The China Scholarship Council is acknowledged for the doctoral scholarship of Haoyu Zheng(201806160173)The German Federal Ministry for Education and Research is acknowledged for funding via the Project ARCADE(03SF0580A)。
文摘Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatures by proton conducting ceramic cell electrolysis(PCCEL).We demonstrate a highperformance steam electrolysis owing to a composite positrode based on BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC1082)and BaZr0.5Ce0.4Y0.1O3-δ(BZCY541).The high reliability of PCCEL is demonstrated for 1680 h at a current density as high as-0.8 A cm^(-2)close to the thermoneutral cell voltage at 600℃.The electrolysis cell showed a specific energy consumption ranging from 54 to 66 kW h kg^(-1)that is comparable to state-of-the-art low temperature electrolysis technologies,while showing hydrogen production rates systematically higher than commercial solid oxide ceramic cells(SOCs).Compared to SOCs,the results verified the higher performances of PCCs at the relevant operating temperatures,due to the lower activation energy for proton transfer comparing with oxygen ion conduction.However,because of the p-type electronic conduction in protonic ceramics,the energy conversion rate of PCCs is relatively lower in steam electrolysis.The faradaic efficiency of the PCC in electrolysis mode can be increased at lower operating temperatures and in endothermic conditions,making PCCEL a technology of choice to valorize high temperature waste heat from industrial processes into hydrogen.To increase the faradaic efficiency by optimizing the materials,the cell design,or the operating strategy is a key challenge to address for future developments of PCCEL in order to achieve even more superior techno-economic merits.
基金Funding Statement:The work was supported by the National Natural Science Foundation of China(51465014)Guangxi Innovation Driven Development Project(Grant No.AA17204021)+1 种基金the Foundation of Guangxi Key Laboratory of Optical and Electronic Materials and Devices(No.20KF-4)Foundation of Introduction of Senior Talents in Hebei Province(H192003015).
文摘In this study,the effect of sintering temperature and the addition of kaolin,a sintering agent,on the microscopic,phase,and mechanical properties of ceramics were investigated using secondary aluminum dross(SAD)as the main component in the manufacturing of ceramics.The basic phases of the ceramics were Al_(2)O_(3),MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2)without the addition of kaolin.The diffraction peaks of MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2)kept decreasing while those of Al_(2)O_(3)kept increasing with an increase in temperature.In addition,the increase in temperature promoted the growth of the grains.The grains were uniform in size and regular in distribution,with a shrinkage of 2.2%,porosity of 72.5%,bulk density of 1.076 g/cm^(3),and compressive strength of 1.12 MPa.When the sintering temperature was 1450°C,the basic phases of the ceramic after the addition of kaolin were Al_(2)O_(3),MgAl_(2)O_(4),NaAl_(11)O_(17),and SiO_(2).With the increase of kaolin,the diffraction peaks of NaAl_(11)O_(17)and SiO_(2)decreased until they disappeared,while the diffraction peaks of Al_(2)O_(3)increased significantly.When kaolin was added at 30 wt.%,the ceramics obtained had shrinkage of 18%,a porosity of 47.26%,a bulk density of 1.965 g/cm^(3),and compressive strength of 31.9 MPa.Cracks existed inside the ceramics without the addition of kaolin,while the addition of kaolin significantly changed this defect.It is shown that SAD can obtain porous ceramics with good properties at a sintering temperature of 1450°C and a kaolin addition of 30 wt.%.
基金Funded by the National Key Research and Development Program of Science and Technology of China(No.2018YFB1501002)。
文摘Mullite thermal storage ceramics were prepared by low-cost calcined bauxite and kaolin.The phase composition,microstructure,high temperature resistance and thermophysical properties were characterized by modern testing techniques.The experimental results indicate that sample A3(bauxite/kaolin ratio of 5:5)sintered at 1620℃has the optimum comprehensive properties,with bulk density of 2.83 g·cm^(-3)and bending strength of 155.44 MPa.After 30 thermal shocks(1000℃-room temperature,air cooling),the bending strength of sample A3 increases to 166.15 MPa with an enhancement rate of 6.89%,the corresponding thermal conductivity and specific heat capacity are 3.54 W·(m·K)^(-1)and 1.39 kJ·(kg·K)^(-1)at 800℃,and the thermal storage density is 1096 kJ·kg^(-1)(25-800 mullite ceramics;sintering properties;high-temperature thermal storage;thermal shock resistance).Mullite forms a dense and continuous interlaced network microstructure,which endows the samples high thermal storage density and high bending strength,but the decrease of bauxite/kaolin ratio leads to the decrease of mullite content,which reduces the properties of the samples.
