多孔陶瓷制备新工艺及其进展

综述了多孔陶瓷的传统制备方法，着重介绍了纤维多孔陶瓷，凝胶注模工艺、气凝胶和木材陶瓷等新兴材料与工艺及其研究进展。分析了多孔陶瓷存在的问题和今后的发展方向。     

梯度多孔陶瓷的制备技术

梯度多孔陶瓷具有高过滤精度、大透气系数、反洗效果好等特点,显示出广阔的应用前景。本文介绍了梯度多孔陶瓷的类别、表征手段和制备方法,重点介绍了一种绿色新工艺—冷冻干燥法的工艺及特点,为梯度多孔陶瓷的产业化发展提供参考。     

多孔陶瓷的制备及应用进展

本文综述了多孔陶瓷的分类及其制备方法,并介绍了多孔陶瓷广阔的应用前景和未来的研究方向。     

多孔陶瓷的制备工艺

介绍了微波加热工艺、颗粒堆积工艺、水热－热静压工艺等制备多孔陶瓷材料的技术,展望了多孔陶瓷材料的发展前景。     

氧化铝多孔陶瓷制备工艺的研究

本研究了氧化铝多孔陶瓷的制备工艺，探讨了制备工艺参数对多孔陶瓷性能的影响。研究结果表明，氧化铝骨料颗粒度是得到不同孔径多孔陶瓷的关键；粘结剂含量对多孔陶瓷的孔隙率、强度有很大影响；烧 是得到性能多孔陶瓷的重要因素。通过改变工艺参数，可以得到平均孔径1至10μm，开气孔率40％的氧化铝多孔陶瓷。     

自蔓延高温合成技术及其制备新材料的研究

介绍了自蔓延高温合成技术的发展和国内外研究的概况,分析了SHS技术研究与发展的几个重要方向,介绍了SHS研究的最新动向。对中国学者在此领域的工作所取得的成果给予了介绍和评价。     

氮化硅基多孔陶瓷的制备与应用进展

多孔氮化硅陶瓷具有优异的抗氧化、抗热震、低介电常数和介电损耗、高孔隙率、优良的机械力学和耐酸碱腐蚀等性能,备受国内研究者的青睐。分析多孔氮化硅陶瓷的制备方法和应用领域的研究进展,展望了多孔氮化硅陶瓷的研究方向。     

多孔陶瓷的制备与应用

综述了多孔陶瓷的类型、性能、制备工艺及其在工业中的应用，并对多孔陶瓷的研究与应用做了展望。     

多孔SiC陶瓷的制备与应用

多孔SiC陶瓷具有高温强度高、抗氧化、耐磨蚀、抗热震、较高的热导率及微波吸收能力等特点,在过滤材料、复合材料骨架、催化剂载体和吸声材料方面应用广泛。本文从产业化及应用的视角,综述多孔SiC陶瓷的多种制备技术及工艺特点,介绍多孔SiC陶瓷的应用情况,展望其发展方向并提出技术发展建议。     

多孔陶瓷的制备,性能及应用

多孔陶瓷性能特点,应用广泛,并为节能等相关行业带来进步。本文对多孔陶瓷的种类,制备,结构与性能表征,应用,国同发展等作了一个概述。     

多孔陶瓷材料的制备研究进展

介绍了多孔陶瓷材料的分类、性能和应用,综述了多孔陶瓷的制备方法,并分析了不同制备方法的特点。     

Preparation of near net size porous alumina-calcium aluminate ceramics by gelcasting-pore-forming agent processs

In the processing of porous ceramics, shrinkage from green body to sintered compact during drying and sintering is one of the key concerns which affect microstructure and properties of porous ceramics. Through releasing gases from the burning of the pore forming agents, and volume expansion from the formation of low density resultants during sintering, the sintering shrinkage can be effectively compensated and near net size preparation can be achieved. Herein, near net size porous alumina-calcium aluminate ceramics with controllable shrinkage have been prepared using a combination of gelcasting and pore-forming agent process by adjusting the amount of CaCO₃ and polymethyl methacrylate (PMMA) microspheres added. Al₂O₃ and CaCO₃ were used as raw materials, PMMA microspheres were used as pore-forming agent, isobutylene/maleic anhydride copolymer (Isobam104) was used as gelling agent and dispersing agent. The effects of the addition amounts of CaCO₃ and PMMA in the slurry on the phase composition, shrinkage, porosity, and strength of porous alumina-calcium aluminate ceramics were investigated. The results show that as the CaCO₃ addition amount increases from 0 to 20 wt%, the shrinkage of the samples gradually decreases from 7.3% to −1.4%, and the consequent porosity increases from 58% to 66%, while the compressive strength increases from 5.9 to 15.5 MPa. When PMMA content increases from 10 to 50 wt%, the shrinkage of the samples decreases first and then increases, the porosity increases from 51% to 74%, and the compressive strength decreases from 12.5 to 5.3 MPa. The mechanisms for controlling shrinkages during preparation of porous alumina-calcium aluminate ceramics can be attributed to the following aspects: on one hand, gas release from burning of PMMA and decomposition of CaCO₃ during sintering; on the other hand, volume expansion due to the formation of lower density calcium aluminates which come from the reactions between CaO and Al₂O₃. The near net size preparation technique is of great significance for the manufacture of porous ceramics since the subsequent machining cost can be effectively reduced.     

生物SiC多孔陶瓷的研究进展

介绍了生物SiC多孔陶瓷的研究现状,并对生物碳模板的分类、制备方法进行了详尽的叙述,同时对生物SiC多孔陶瓷的各项性能进行了综述,最后对生物SiC多孔陶瓷的发展趋势作了总结。     

Preparation of elongated mullite self-reinforced porous ceramics

Elongated mullite was synthesized using mullite powder as a raw material and AlF₃·3H₂O as an additive, and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The effects of AlF₃·3H₂O content and reaction temperature on the formation of elongated mullite were investigated, and the relevant growth mechanism was discussed based on the experimental results and density functional theory (DFT) calculations. When the optimal amount of AlF₃·3H₂O (4?wt% in the present work) was used, the length and diameter of elongated mullite increased with increasing the reaction temperature, and elongated mullite of 22.3?µm in average length and 4.6?µm in average diameter was formed after 5?h at 1873?K. Based on the results, elongated mullite self-reinforced porous ceramics were prepared by a combined foam-gelcasting and solid-reaction method, and their mechanical properties were examined. Elongated mullite in-situ formed in the porous samples evidently enhanced their mechanical strength. The flexural strength of the elongated mullite self-reinforced porous sample with 67.0% porosity (prepared using 6?wt% AlF₃·3H₂O) was as high as 13.9?MPa, which was about 26.4% higher than that of a porous sample (11.0?MPa) prepared without AlF₃·3H₂O.     

Preparation and properties of magnesia porous ceramics by particle-stabilized foam casting

In this paper, magnesia porous ceramics were prepared by particle-stabilized foams assisted foam-gel casting. Secondly, the performance of magnesia slurry and magnesia porous ceramics was investigated. The obtained magnesia powder manifested high adsorption amount and excellent hydrophobicity, due to the strong adsorption ability of sodium dodecyl benzene sulfonate (SDBS) on magnesia particles. When the SDBS concentration is .3 wt%, the surface tension and expansion ratio of the slurry were 45 mN·m⁻¹ and 1.68, respectively. The shape of the pore was sphere cell structure, with uniform distribution of pores in the sample, the average pore size was in the range of 58.7–73.9 μm, and the compressive strength was in the range of 25.3 MPa to 15.5 MPa when porosity varied from 56.7% to 70.2%.     

Near-net-size preparation of porous mullite matrix ceramics with in situ formed 3D mullite whisker network

Porous mullite matrix ceramics have excellent thermal and mechanical properties suitable for applications such as in thermal insulation. However, their applications are limited by processing defects from nonuniform sintering shrinkage and the trade-off between high porosity (preferred for low thermal conductivity) and high mechanical strength. Herein, we seek to minimize the sintering shrinkage by near-net-size preparation and improve the strength by in situ formed whisker network structure. Gelcasting forming technology and pressureless sintering were used to prepare porous mullite matrix ceramics using kyanite and α-Al₂O₃ powders as the starting materials and using MoO₃ to promote the growth of mullite whiskers. The results showed that the sintering shrinkage could be compensated by the volume expansion from solid-state reaction during reaction sintering. The in situ formed three-dimensional (3D) whisker network further reduced sintering shrinkage and effectively improved the strength of the ceramics. An ultralow sintering shrinkage of .78% was achieved. The near-net-shape porous mullite matrix ceramics strengthened by 3D whisker network had a high porosity of 63.9%, a high compressive strength of 83.8 MPa and a high flexural strength of 53.5 MPa.     

泡沫注凝法制备刚玉-莫来石多孔陶瓷

以T60板状刚玉粉(d50=10.74μm)、ZTP-200氧化铝微粉(d50=4.96μm)、RG4000煅烧氧化铝微粉(d50=1.46μm)和NS-30型硅溶胶为原料,采用泡沫注凝法制备了刚玉-莫来石多孔陶瓷,主要研究了粉料粒度级配(d50分别为1.46、4.96、10.74μm的三种氧化铝粉料的质量分数分别为44%、26%、30%,36%、28%、36%,30%、29%、41%,21%、29%、50%)和浆料中硅溶胶加入量(质量分数分别为0、2%、4%)对坯体的烧后收缩及烧后试样的致密度、常温耐压强度、热导率、相组成和显微结构的影响。结果表明:1)d50=10.74μm的粗颗粒加入量增加,试样的烧后线收缩率、致密度和常温耐压强度减小;2)硅溶胶加入量增加,试样的烧后线收缩率和体积密度减小,但由于SiO2与Al2O3反应生成莫来石,试样的常温耐压强度变化较复杂;3)泡沫注凝法制备的刚玉-莫来石复相多孔陶瓷具有球形孔结构,平均孔径约为140μm,其性能如下:烧后线收缩率9.29%,体积密度0.78 g·cm-3,显气孔率79.8%,常温耐压强度25.3 MPa,1 000℃(热面温度)下的热导率为0.481W·m-1·K-1。     

Preparation and characterization of porous anorthite ceramics from red mud and fly ash

The porous anorthite ceramics with high porosity, good mechanical strength and low heat conductivity were prepared using red mud and fly ash as raw materials via the pore forming method. The effects of sintering temperature and fly ash on phase evolution, densification, compressive strength, thermal conductivity and microstructure of the ceramic materials were investigated. The results showed that the compressive strength of the porous ceramics had an obvious improvement with the increase in fly ash, and the densification and heat conductivity decreased firstly and then increased. In particular, specimen S2 containing 30 wt% red mud and 40 wt% fly ash sintered at 1150°C had the better performances. It had the water absorption of 18.18%, open porosity of 38.52%, bulk density of 1.29 g/cm³, compressive strength of 42.46 MPa, and heat conductivity of 1.24 W/m·K. X-ray diffraction analysis indicated that mullite, anorthite, α-quartz, and diopside ferrian were the dominant phases in the specimens. Scanning electron microscopy micrographs illustrated that plenty of open pores with strip shape and closed pores with axiolitic shape existed in the specimens. Furthermore, the existence of mullite could prevent crack propagation to enhance the energy of inter-granular fracture. It endowed the porous anorthite ceramics with high porosity, good compressive strength, and low heat conductivity.     

钛酸铅系电子陶瓷及粉体的制备方法

综述了钛酸铅系电子陶瓷及粉体的制备方法，主要讨论了水热法和溶胶一凝胶法的制备原理及影响产物性能的因素。为钛酸铅系功能陶瓷及材料的研究指明了方向。即用最新方法制备超纯、超细粉体，以先进技术指导合成降低反应温度并制备出功能复合材料。     

Preparation and characteristics of highly porous BN-Si3N4 composite ceramics by combustion synthesis

Nitride based ceramics are considered as a kind of promising material for structural and functional integration due to their robust structure, extreme environmental resistance and electromagnetically transparency. It is still challenging to prepare nitride based ceramics with homogeneous and controllable microstructure because of their low self-diffusion coefficient and difficulty in sintering. Here, we developed a gelcasting-SHS process by combining gelcasting forming and self-propagating high temperature synthesis (SHS) for the preparation of porous BN-Si₃N₄ composite ceramics. First, carbon residue problem in the gelcasting -SHS process was studied. Based on the result, porous BN-Si₃N₄ composite ceramics with high porosity (69.42 ~ 86.48%), high strength (21.7 ~ 81.0 MPa) and low dielectric constants (1.42 ~ 2.87) were synthesized. In addition, the thermal shock resistance of porous BN-Si₃N₄ composite ceramics until 1000 ℃ was evaluated.