共查询到19条相似文献,搜索用时 116 毫秒
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采用发泡法与添加造孔剂相结合,以高铝矾土和高岭土为骨料,长石作熔剂,并添加适量的煤、MgSO4和CaSO4作发泡剂,煤为造孔剂,PVA为粘结剂,干压成型后于1500℃左右烧成制备了莫来石质多孔陶瓷。制得的多孔陶瓷莫来石生成量高达90%以上,其气孔分布均匀,孔径分布范围为100~300μm;气孔率高达52.3%(闭孔气孔率为38.7%,开孔气孔率为13.6%);体积密度为0.9731g/cm3;抗压强度为25.1317MPa;导热系数为0.143W/(m.K)的多孔陶瓷。 相似文献
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多孔羟基磷灰石(HA)陶瓷内部结构满足细胞向内部渗透、迁移、粘附和生长的条件。实验探讨了HA陶瓷内部成孔与孔道连结的机理与技术,采用添加制孔剂和固化纤维2种方法制备系列样品,测算了样品气孔率,并对微观结构进行扫描电镜观察,最终确定可人工调控内部结构的HA陶瓷成孔与贯通技术。 相似文献
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以炭粉作追孔剂,制备了孔径在50nm-1mm的多孔羟基磷灰石陶瓷。运用TG—DTA、SEM等测试手段对产品的微观形貌、力学性能进行了测试分析,并对烧结温度、炭粉加入量、玻璃粉加入量这些影响陶瓷体性能的工艺参数进行了研究。 相似文献
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Kiyoshi Matsuyama Kenji MishimaTakafumi Kato Kiyomi Ohara 《The Journal of Supercritical Fluids》2011,57(2):198-206
The formation of porous glass ceramic via core/shell-structured poly(methyl methacrylate)(PMMA)/powder glass was investigated. Core/shell structures were prepared via ultrasonic irradiation in high-pressure liquid carbon dioxide (CO2) using PMMA microspheres as the core material and glass powder as the shell material. The mean particles sizes of PMMA template microspheres and glass powder were 9.8 μm and 0.9 μm, respectively. After removal of the PMMA template by calcination in air, porous glass was obtained. The products were characterized by scanning electronic microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). The average pore diameter of porous glass was 4.3 μm. Compared with porous glass prepared by the other method, the porous glass prepared by ultrasonic irradiation of liquid CO2 was achieved the narrow pore size distribution (CV = 35%) and the higher porosity (89%). The pores are not isolated and connected each other. Furthermore, the effects of experimental conditions, such as coating method, crosslink density of the template PMMA microspheres, ultrasonic intensity and calcination temperature, on the product morphology were investigated. The higher ultrasound intensity achieved the uniform coating of PMMA templates with powder glass. The calcination temperature and crosslinked density of PMMA template microspheres affect the pore structure. 相似文献
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《Ceramics International》2022,48(6):8031-8038
In this work, we showed that immersing polymethyl methacrylate (PMMA)/poly alpha olefins (PAO6) microcapsules into the porous matrix can improve the lubrication properties of porous alumina ceramics dramatically. PMMA/PAO6 microcapsules were synthesized by microemulsion polymerization, and the microcapsules were immersed in the porous alumina ceramic matrix by vacuum impregnation. The lubrication behaviors of the porous alumina ceramics with PMMA/PAO6 microcapsules have been investigated under different loads. As compared with the unprocessed porous alumina ceramics, the coefficient of friction (COF) of the porous ceramics impregnated with microcapsules could be reduced to 4% of that without microcapsules, and the wear rate could be reduced by two orders of magnitude. No obvious change of the COF was noticed for the matrices with different pore sizes. The good self-lubrication properties were achieved by releasing the PAO6 in the microcapsules during the friction process. 相似文献
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分别以平均粒径为10μm和20μm的两种规格碳化硅(SiC)粉末为原料、聚碳硅烷(PCS)为粘结剂,通过包混、过筛、模压成型、1000℃热解等工序制备了SiC多孔陶瓷,研究了PCS含量对SiC多孔陶瓷微观形貌、线收缩率、孔隙率与抗弯强度的影响,并对两种规格粉末制备的SiC多孔陶瓷性能进行了对比。结果表明:随着PCS含量的增加,两种规格粉末制备的SiC多孔陶瓷微观形貌都逐渐变得致密,当PCS含量为13%时,两种规格粉末制备的多孔陶瓷都出现了微观裂纹。随着PCS含量的增加,两种规格粉末制备的SiC多孔陶瓷孔隙率都逐渐降低,线收缩率都逐渐增大,抗弯强度先增大后降低,在PCS含量为10%时,平均粒径为10μm与20μm的SiC粉末制备的多孔陶瓷抗弯强度取得最大值,分别为31.6MPa与29.0MPa。 相似文献
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以镁渣,粉煤灰为原料,添加造孔剂(电石渣、碳粉)和增强剂(高岭土、膨润土)制备多孔陶瓷,并研究造孔剂和增强剂种类和含量对多孔陶瓷性能的影响.结果表明,添加造孔剂后,多孔陶瓷的烧失率、吸水率和气孔率升高,体积密度和强度降低.同等含量时,碳粉具有较好的造孔效果;多孔陶瓷的烧失率、吸水率和气孔率最高可分别达到30%,38%和53%,体积密度最小达到1.4 g/cm3;添加增强剂后,多孔陶瓷的强度大为提高,但其吸水率、气孔率降低,体积密度增加.高岭土的含量不大于10%时,其粘结增强效果明显优于同等含量膨润土的;多孔陶瓷的压缩强度可至28 MPa. 相似文献
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Porous yttria-stabilized zirconia (YSZ) ceramics were successfully fabricated by the dry pressing method with different size (1.8–20 μm) and amount (2–60 vol.%) of mono-dispersed poly methyl methacrylate (PMMA) micro-balls. Different PMMA additions with different size and amount were investigated to achieve optimal thermal and mechanical properties. With increases of the amount of PMMA, the porosity of porous YSZ ceramics ranges from 7.29% to 51.6%, the flexural strength increases firstly and then decreases, and the thermal conductivity decreases continuously. With decreases of the diameter of PMMA micro-balls, the mean pore size and thermal conductivity of porous YSZ ceramics decrease, and the flexural strength of porous YSZ ceramics with same porosity increases firstly and then decreases. The porous YSZ ceramics with a higher porosity (18.44 ± 1.24%), the highest flexural strength (106.88 ± 3.2179 MPa) and low thermal conductivity (1.105 ± 0.15 W/m K) can be obtained when the particle diameter and the amount of PMMA are 5 μm and 20 vol.%, respectively. 相似文献
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Bian-Lei Hao Ying Lang Da-Qian Bian Chang-An Wang 《Journal of the American Ceramic Society》2020,103(8):4602-4610
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. 相似文献
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Jingxiong Liu Hanning Xiao Wenming Guo Pengzhao Gao Jianjun Liang 《Ceramics International》2018,44(4):3830-3836
Spherical SiC powders were prepared at high temperature using commercial SiC powders (4.52 µm) with irregular morphology. The influence of spherical SiC powders on the properties of SiC porous ceramics was investigated. In comparison with the as-received powders, the spheroidized SiC powders exhibited a relatively narrow particle size distribution and better flowability. The spheroidization mechanism of irregular SiC powder is surface diffusion. SiC porous ceramics prepared from spheroidized SiC powders showed more uniform pore size distribution and higher bending strength than that from as-received SiC powders. The improvement in the performance of SiC porous ceramics from spheroidized powder was attributed to tighter stacking of spherical SiC particles. After sintering at 1800 °C, the open porosity, average pore diameter, and bending strength of SiC porous ceramics prepared from spheroidized SiC powder were 39%, 2803.4 nm, and 66.89 MPa, respectively. Hence, SiC porous ceramics prepared from spheroidized SiC powder could be used as membrane for micro-filtration or as support of membrane for ultra/nano-filtration. 相似文献
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Fang‐Fang Wu Xue‐Ping Li Hong Zhong Shuai Wang 《International Journal of Applied Ceramic Technology》2016,13(3):511-521
Electrolytic manganese residues (EMR) are one of industrial by‐products generated during the production of electrolytic manganese metal. To reduce the EMR hazard to environment and invent value‐added materials, porous ceramics were prepared by the pore‐forming method with EMR and various additives. The influences of the incorporation of different additives, sintering temperature, and molding pressure on properties of porous ceramics were investigated. Properties such as apparent porosity, water absorption, bulk density, and compression strength have been measured. The EMR‐based porous ceramics were also characterized by XRD, SEM, BET‐specific surface area, and BJH pore size distribution measurement. It revealed that the appropriate mode was the sample containing 20 wt% carbon powder, 7.5 wt% dolomite, and 5 wt% kaoline, under which the ceramics with the properties of high apparent porosity (69.70%), high compressive strength (6.97 MPa), and good acidity–alkali stability were obtained successfully. The comprehensive performance of EMR‐based porous ceramics makes them advantageous to use as nonhazardous and valuable materials showing promising potential applications, which not only is a promising new approach to improve the resource utilization of EMR but also can promote the manganese industry's sustainable and healthy development and protect and improve ecological environment. 相似文献