Progress in Research on Structural Ceramic Materials Toughened by Graphene

Graphene has excellent mechanical properties and unique physical/chemical properties,which make it have a good strengthening and toughening effect on structural ceramic materials.In recent years,it has received widespread attention and research.This article reviews the mixing and sintering processes in the preparation of graphene/ceramic com-posites,as well as the toughening mechanism of graphene on ceramic materials.It also looks forward to how to further enhance the toughening effect of graphene.

Research Progress of High Entropy Ceramic Materials

High-entropy materials(HEMs)have better mechanical,thermal,and electrical properties than traditional materials due to their special"high entropy effect".They can also adjust the performance of high entropy ceramics by adjusting the proportion of raw materials,and have broad application prospects in many fields.This article provides a review of the high entropy effect,preparation methods,and main applications of high entropy ceramic materials,especially exploring relevant research on high entropy perovskite ceramics.It is expected to provide reference for the promotion of scientific research and the development of further large-scale applications of high-entropy ceramic materials.

Strengthening Mullite Ceramic Materials by Gas Infiltration

In order to improve the high-temperature performance of mullite ceramic materials,mullite ceramic bodies were placed in closed containers with AlF_(3)·3H_(2)O powder and kept at 1 600 ℃ for 6 h.AlF_(3)·3H_(2)O reacts with O_(2) to produce gaseous compounds AlOF and F,which penetrate into the bodies,promote Al2O3 and SiO_(2) to form mullite whiskers,and strengthen the mullite ceramic materials.The results show that the mullite ceramics have enhanced hot strength,increased bulk density and declined apparent porosity by adding a certain amount of AlF_(3)·3H_(2)O in a closed container.When the addition of AlF_(3)·3H_(2)O is 6%,the bulk density of the ceramic material reaches the maximum and the apparent porosity is the lowest;and when the addition of AlF_(3)·3H_(2)O is 8%,the hot strength of the material is the highest.

Development and Application of Modern Building Ceramic Materials

With the increasing demand for sustainable building design,modern building ceramic materials are one of the key factors driving innovation and development in the field of architecture,thanks to their excellent performance and environmentally friendly properties.The aim of this study is to provide an insight into the development and application of building ceramic materials in modern architecture,and to assess the contribution of material innovation to architectural design and sustainability goals by synthesising and analysing recent technological advances and case studies in this field.This study adopts a systematic literature review approach to screen and analyse a large number of academic articles and practical project reports on material innovation in building ceramics.Comparative analyses of different material properties,advances in production processes and the effects of their application in real building projects reveal the potential of building ceramic materials to improve the energy efficiency,extend the service life and enhance the aesthetic design of buildings.The findings show that the environmental and energy issues facing traditional building materials,such as improved thermal efficiency and a reduction in the overall carbon footprint of buildings,can be effectively addressed through the use of new building ceramic materials and technologies.In addition,the innovative use of architectural ceramics provides architects with more design flexibility,enabling them to create architectural works that are both aesthetically pleasing and functional.In the concluding section,the paper highlights the importance of continuing to explore technological innovations in building ceramic materials and how these innovations can contribute to a more sustainable and environmentally friendly building industry.Future research should further explore new areas of application for ceramic materials and how interdisciplinary collaboration can accelerate the practical application of these material technologies.

Porous high-entropy rare-earth phosphate(REPO_(4),RE=La,Sm,Eu,Ce,Pr and Gd)ceramics with excellent thermal insulation performance via pore structure tailoring

Thermal insulation materials play an increasingly important role in protecting mechanical parts functioning at high temperatures.In this study,a new porous high-entropy(La_(1/6)Ce_(1/6)Pr_(1/6)Sm_(1/6)Eu_(1/6)Gd_(1/6))PO_(4)(HE(6RE_(1/6))PO_(4))ceramics was prepared by combining the high-entropy method with the pore-forming agent method and the effect of different starch contents(0–60vol%)on this ceramic properties was systematically investigated.The results show that the porous HE(6RE_(1/6))PO_(4)ceramics with 60vol%starch exhibit the lowest thermal conductivity of 0.061 W·m^(-1)·K^(-1)at room temperature and good pore structure stability with a linear shrinkage of approximately1.67%.Moreover,the effect of large regular spherical pores(>10μm)on its thermal insulation performance was discussed,and an optimal thermal conductivity prediction model was screened.The superior properties of the prepared porous HE(6RE_(1/6))PO_(4)ceramics allow them to be promising insulation materials in the future.

Thermodynamic analysis and formula optimization of steel slag-based ceramic materials by FACTsage software

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.

Influence of Composite Phosphate Inorganic Antibacterial Materials Containing Rare Earth on Activated Water Property of Ceramics

Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of (()^(17)O-NMR) for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.

Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials

Two types of porcelain tiles with steel slag as the main raw material （steel slag ceramics） were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite, a-quartz, magnetite, and pyroxene crystals （augite and diopside） in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction （XRD） and electron probe X-ray microanalysis （EPMA） results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

Development and application of ferrite materials for low temperature co-fired ceramic technology

Development and application of ferrite materials for low temperature co-fired ceramic （LTCC） technology are dis- cussed, specifically addressing several typical ferrite materials such as M-type barium ferrite, NiCuZn ferrite, YIG ferrite, and lithium ferrite. In order to permit co-firing with a silver internal electrode in LTCC process, the sintering temperature of ferrite materials should be less than 950 ℃. These ferrite materials are research focuses and are applied in many ways in electronics.

CERAMICS AS CANDIDATE STRUCTURAL MATERIALS FOR CRYOGENIC APPLICATIONS

The use of zirconia-based ceramic materials as smpport materidls for superconducting magnets and in cryopenic engineeriny generally has been considered. The relationship between compsition and mechanical properties at cryogenic temperature has also been investigated.

Effects of Rare Earth Elements on Wear Resistance of Ceramic Tool Materials

Through the addition of Y, Sm and Ce in Al2O3/(W, Ti)C ceramic matrix, it was found that the amount and kind of the added rare earth elements have some different influences on the mechanical properties and wear resistance of the composite. Under the present experimental conditions, the flank wear curves of the selected ceramic tool materials when machining the hardened tool steel obeyed the wear law well. But wear resistance of different ceramic materials varied with each other. Wear resistance of rare earth ceramic tool materials was higher than that of the corresponding materials without rare earth. Wear modes of the developed Al2O3/(W, Ti)C series rare earth ceramic tool materials were mainly flank wear and accompanied with slight crater wear.

Potentiality of Clay Raw Materials from Northern Morocco in Ceramic Industry: Tetouan and Meknes Areas

This study aims at evaluating the potential suitability of Tetouan and Meknes (central Morocco) clay material as raw materials in various ceramic applications by investigating their textural, chemical, thermal and firing characteristics. Textural properties were identified by specific surface area, cation exchange capacity (CEC) and bulk density (ρs). Chemical and thermal properties were assessed using XRF and TG/DTA techniques, respectively. Firing characteristics at temperatures from 800℃ to 1100℃ were determined by linear firing shrinkage, loss on weight and water absorption capacity. The Meknes clays are characterised by medium cation exchange capacity (CEC) and specific surface area (SSA) values due to their moderate smectite content. The Tetouan clays have medium to low CEC and medium SSA values. The main oxides in the clayey samples are SiO2 (35 - 54.3 wt%), Al2O3 (20.6 - 43.9 wt%), and Fe2O3 (9.7 - 22.4 wt%). The amount of CaO in Meknes clays ranges from 8 to 12 wt%, whereas CaO is only present in some Tetouan clay (TE4, TE7, TN4 and TN5). A significant densification of ceramic behaviour could be noticed for most of Tetouan clays at firing temperatures above 1000℃. Meknes clays show earlier densification from 800℃. The chemical, textural and ceramic properties of Tetouan and Meknes clays indicate their suitability as raw materials for the production of structural ceramics. The high amount of Fe2O3 in all clays makes them inappropriate in fine ceramics.

Preparation and characterization of ceramic materials with low thermal conductivity and high strength using high-calcium fly ash

High calcium-fly ash(HCFA)collected from the Mae Moh electricity generating plant in Thailand was utilized as a raw material for ceramic production.The main compositions of HCFA characterized by X-ray fluorescence mainly consisted of 28.55wt%SiO_(2),16.06wt%Al_(2)O_(3),23.40wt%CaO,and 17.03wt%Fe_(2)O_(3).Due to high proportion of calcareous and ferruginous contents,HCFA was used for replacing the potash feldspar in amounts of 10wt%-40wt%.The influence of substituting high-calcium fly ash(0-40wt%)and sintering temperatures(1000-1200℃)on physical,mechanical,and thermal properties of ceramic-based materials was investigated.The results showed that the in-corporation of HCFA in appropriate amounts could enhance the densification and the strength as well as reduce the thermal conductivity of ceramic samples.High proportion of calcareous and ferruginous constituents in fly ash promoted the vitrification behavior of ceramic samples.As a result,the densification was enhanced by liquid phase formation at optimum fly ash content and sintering temperature.In addition,these components also facilitated a more abundant mullite formation and consequently improved flexural strength of the ceramic samples.The op-timum ceramic properties were achieved with adding fly ash content between 10wt%-30wt%sintered at 1150-1200℃.At 1200℃,the max-imum flexural strength of ceramic-FA samples with adding fly ash 10wt%-30wt%(PSW-FA(10)-(30))was obtained in the range of 92.25-94.71 MPa when the water absorption reached almost zero(0.03%).In terms of thermal insulation materials,the increase in fly ash addi-tion had a positively effect on the thermal conductivity,due to the higher levels of porosity created by gas evolving from the inorganic decom-position reactions inside the ceramic-FA samples.The addition of 20wt%-40wt%high-calcium fly ash in ceramic samples sintered at 1150℃reduced the thermal conductivity to 14.78%-49.25%,while maintaining acceptable flexural strength values(~45.67-87.62 MPa).Based on these promising mechanical and thermal characteristics,it is feasible to utilize this high-calcium fly ash as an alternative raw material in clay compositions for manufacturing of ceramic tiles.

High Efficiency Axial Deep Creep-Feed Grinding Machining Technology of Engineering Ceramics Materials

Axial deep creep-feed grinding machining technology is a high efficiency process method of engineering ceramics materials, which is an original method to process the cylindrical ceramics materials or hole along its axis. The analysis of axial force and edge fracture proved the cutting thickness and feed rate could be more than 5-10 mm and 200 mm/min respectively in once process, and realized high efficiency, low-cost process of engineering ceramics materials. Compared with high speed-deep grinding machining, this method is also a high efficiency machining technology of engineering ceramics materials as well as with low cost. In addition, removal mechanism analyses showed that both median/radial cracks and lateral cracks appeared in the part to be removed, and the processed part is seldom destroyed, only by adjusting the axial force to control the length of transverse cracks.

Preparation and Effect of Rare Earth Composite Ceramic Materials on Reducing Exhaust Emissions

Rare earth composite ceramic materials (RE/CM) were prepared by the method of firing the mixtures of the rare earth elements, polar crystal mineral materials and clays. The effects of processing method on the reducing exhaust emissions were studied. The results show that after dealt with the ceramic balls, the surface tension of gasoline, and the CO concentration among exhaust emissions during combustion, decrease by 2.7% and 11.5%, respectively; however the temperature of the inner flue increases by 4.8%.

STUDY ON THE STRUCTURE AND PROPERTIES OF SEMICONDUCTOR CERAMIC COOLING MATERIALS

In this paper, thermoelectric polycrystal ceramic materials were prepared by a new ceramic technology. The p-type 72% Sb2Te3+ 25%Bi2Te3 + 3%Sb2Se3 doped with Te and 90%Bi2Te3 + 5%Sb2Te3 + 5%Sb2Se3 doped with SbI3 or AgI samples were studied. The new ceramic cooling materials have an inhomo-geneous structure, higher mechanical strength and the thermoelectric properties. With the help of phase diagrams, Differantial Thermal Analysis, X-Ray diffractograms, the observation of high temperature microscope and the relation between technology conditions and thermoelectric properties were obtained in optimum technology conditions. Measurements of properties show that the sintering temperature and time have an effect on the thermoelectric properties of the samples. Scan electronic microscope shows that the polycrystal ceramic materical has an obvious layered structure. Electrical probe microscope analysis indicates that the mol contents of Bi, Te,Sb and Se which compose samples are re- spectively comsistent with original compositions. The distribution of these elements in the samples is well uniform. Doping materials has been studied including doping variety and doping concentration. The figure of merit of n-type doped SbI3 is 2.9 × 10-3 1/k. The figure of merit of p-type doped Te is 3. 1 ×10-3 1/ K.

Composition,Processing Technology and Property of Ceramic Die Materials Containing Rare Earth Additives

Development and application of new ceramic die materials is one of the important topics in the field of die research. The composition, processing technology, mechanical property and engineering performance of the ceramic materials such as cermet, ZTA, TZP, TZP/Al2O3, TZP/TiC/Al2O3, PSZ and Sialon, etc., with rare earth yttrium, lanthanum and cerium, and so on working as additives, were investigated and analyzed in the present study. Problems existed in the research and application of rare earth ceramic die materials were discussed. Rare earth additives can effectively improve the mechanical property and engineering performance of ceramic die materials. Thus, it will have further perspectives of wider application. More attention should be paid in the future to the toughening and strengthening of the ceramic die materials, the adding forms and kinds of rare earth elements and acting mechanisms of rare earth additives in ceramic die materials.

Tribological Properties of Self-lubricating Laminated Ceramic Materials

In order to improve the tribological properties of ceramic composites, Al2O3/TiC-Al2O3/ TiC/CaF2 self-lubricating laminated ceramic composites were prepared by vacuum hot pressing sintering. Experiments were conducted to get mechanical properties and the friction and wear properties were also measured with friction and wear tester. The worn surfaces were observed by scanning electron microscope （SEM） and energy dispersion spectrum （EDS）. The wear resistance properties and the self-lubricating effect of ceramic composites were analyzed. Results show that the Al2O3/TiC-Al2O3/TiC/CaF2 self-lubricating laminated ceramic composites layers are well-defined with a higher bonding strength and the mechanical performances are uniform enough to overcome the anisotropy of weak laminated ceramic composites. In addition, the fracture toughness of Al2O3/TiC layers is also improved. Its friction coefficient and wear rates decrease with the increase of rotation speed and load. Al2O3/TiC-Al2O3/TiC/CaF2 self-lubricating laminated ceramic composites have good wear resistance because of the tribofilm formed by the CaF2 solid lubricants. The wear mechanisms of Al2O3/TiC/ CaF2 layers are abrasive wear and Al2O3/TiC layers are adhesive wear.

Corrosion Resistance of Ceramic Materials in Metallic Neodymium and NdF_3-LiF-Nd_2O_3 System

Corrosion resistant properties of Si3N4-SiC and TiB2 at high temperature were studied. The experiments were carried out in metallic neodymium and NdF3-LiF-Nd2O3 system, respectively. Corrosion temperature was 1100 ℃ and the holding time of corrosion experiments was 24 h. Corrosion products were analyzed by XRD and SEM, and corrosion behavior and corrosion mechanism of the experiments were studied. The results showed that Si3N4-SiC was corroded seriously in the above-mentioned two systems. A few of compounds were found on the surface of Si3N4-SiC, and surface structure of the Si3N4-SiC samples was loosened. The corrosion resistance of TiB2 was better than that of Si3N4-SiC. Oxidation resistance of TiB2 at high temperature should be enhanced.

Study on Thermal Expansion Coefficient of Sealing Materials for Ceramic Metal Halide Lamps

With Al2O3, Dy2O3, and SiO2 as starting materials, the basic glass of Al2O3-Dy2O3-SiO2 system was prepared by conventional melting technology, and their thermal expansion coefficients （TECs） at different anneal time were investigated. TECs of the basic glass, which were heat-treated under different temperature, were also investigated. The result showed that TECs of the basic glass gradually approached a fixed value as the anneal time was extended, which suggested that most of the inner stress had been eliminated. After heat treatment, the contents of Dy2O3, Dy2Si2O7, and a new crystal increased up to 1200 ℃ and decreased below 1250 ℃, which was consistent with the TEC change of crystallized samples. This suggests that the crystal has a direct effect on TECs of the crystallized samples.