镁渣多孔陶瓷滤球气孔率的调控

以镁工业废渣为主原料,添加一些成孔剂及天然矿物烧结助剂,制备了可用于工业废水及废气处理的高性能镁渣多孔陶瓷滤球。讨论了3种成孔剂的成孔效果和影响气孔率、强度的因素。理化性能和显微结构测试表明,高温成孔剂石墨添加量为20%,烧成温度为1100℃时,样品的显气孔率为56.17%,吸水率为43.76%,体积密度为1.28g/cm3,抗压碎强度为34.21MPa,耐酸性为99.59%,耐碱性为99.81%;低温成孔剂煤粉和白云石的加入也能起到气孔率调控的作用。镁渣多孔陶瓷滤球的气孔分布均匀,呈三维连通状,有利于实现其过滤性能。     

利用淤泥研制环保陶瓷滤球

本文通过对武汉钢铁泵站淤泥的分析研究,以煤粉为成孔剂．添加适量粘土,制备了可用于液-固、气-液、液-液及气-气分离的多孔陶瓷滤球,并确定了配方组成与最佳制备工艺结果表明．样品的显气孔率为57．18％,吸水率为41．35％,体积密度为1．38g／cm^3,压碎强度为6．16MPa．     

高孔隙率多孔陶瓷滤料的制备

以漂珠为骨料，以小米或聚苯乙烯颗粒、碳粉等为造孔剂，制得显气孔率为66．43％的高孔隙率多孔陶瓷滤料。通过SEM及性能测试手段，对多孔陶瓷滤料样品性能及其影响因素、微观结构和活化机理作了详细分析与探讨。关键词：高孔隙率，多孔陶瓷滤料，微观结构，活化。     

生物陶瓷内部成孔与贯通方式的研究

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。     

正交设计优化粉煤灰-煤矸石质多孔陶粒的制备过程

以粉煤灰为主要原料,采用添加造孔剂法制备出了多孔陶粒。为了优化工艺参数,得到性能较好的粉煤灰多孔陶粒,通过正交试验设计,系统地研究了煤矸石的掺量、成孔剂、烧结温度对多孔陶粒的物理化学性能的影响,如气孔率、吸水率、抗压碎强度、物相组成和显微形貌等。研究结果表明,成孔剂是影响多孔陶粒性能的最主要因素。当煤矸石掺量20%、成孔剂15%,经1160℃烧成的多孔陶粒样品有着较大的抗压碎强度,显气孔率也达到58.22%。样品的晶相组成为钙长石,及少量的方石英和赤铁矿。其内部孔隙丰富,大孔与小孔交错分布,是一种兼具较高气孔率和较强力学强度的优质多孔陶瓷。     

Al2O3多孔陶瓷的制备和性能研究

采用乙基纤维素为成孔剂制备了Al2O3多孔陶瓷,探讨了工艺参数对其性能的影响。研究结果表明,造孔剂含量、球磨时间及烧结温度均对多孔陶瓷的气孔率和抗折强度有影响。烧结温度的升高使得气孔率降低,但变化不明显,抗折强度明显提高。随造孔剂含量的升高,使得气孔率逐渐上升,超过20％后变化趋于平稳。随着球磨时间的增加,试样呈现气孔率下降和抗折强度升高的趋势。以烧结温度为1580℃,造孔剂含量20％;球磨时间为2．5h的条件下,可获得高显气孔率、抗折强度较高的舢203多孔陶瓷。     

不同铝源对SiC/堇青石复相多孔陶瓷的制备及性能影响

以碳化硅、氮化铝、层析氧化铝、氢氧化铝、氟化铝、滑石为主要原料,石墨为造孔剂通过原位反应烧结技术制备碳化硅/堇青石复相多孔陶瓷.研究了含铝化合物种类、烧结温度、石墨含量对SiC/堇青石复相多孔陶瓷相组成、微观结构、气孔率和抗折强度的影响,同时对S0组在1200℃烧结温度下制得的SiC/堇青石复合多孔陶瓷的孔径分布进行了测试分析.结果表明:以AlN为铝源在1200℃下烧结,石墨含量在15％时,堇青石结合SiC多孔陶瓷的抗弯强度和气孔率两项综合性能达到最优,气孔率为31.99％,相应的弯曲强度86.20 MPa.S0组的平均孔径大小在3.0191 μm.     

孔隙率和孔径对反应烧结多孔氮化硅陶瓷介电性能的影响

研究添加成孔剂法制备的有球形宏观孔的多孔氮化硅陶瓷在不同孔隙率和孔径下的介电性能.通过控制成孔剂苯甲酸的加入量和调节成孔剂的粒径可达到烧结体的气孔率和孔径可控的目的.结果表明:随着成孔剂量的增加,样品气孔率变大,反应烧结后烧结体中的α-Si3N4相增多,样品的介电常数ε'和介电损耗tanδ降低.在成孔剂加入的质量分数为30%时,随着成孔剂的粒径变大,反应烧结后烧结体中气孔的直径变大而气孔率不变,样品的ε'和tan δ也相应降低.得到的样品中最低的ε'值为2.4297.     

造孔剂和增强剂对工业固废基多孔陶瓷性能的影响

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.     

碳化硅/堇青石复相多孔陶瓷的制备及性能研究

采用碳化硅、烧高岭土、氢氧化铝、滑石为主要原料,石墨为造孔剂制备了碳化硅/堇青石复相多孔陶瓷.研究了烧结温度和烧结助剂二氧化铈对碳化硅/堇青石复相多孔陶瓷气孔率和强度的影响,并分别用XRD和SEM分析晶相组成和断面显微结构表明:制备出的SiC多孔陶瓷的主相是SiC,结合相是堇青石与方石英,多孔陶瓷具有相互连通的开孔结构;在1350℃烧结,并保温3h,当造孔剂含量为15％时,碳化硅/堇青石复合多孔陶瓷性能最佳,其气孔率31.80％,相应的弯曲强度为63.74 MPa.在1200℃下,添加不同含量的CeO2,对烧结样品的相组成有影响,能够降低生成堇青石的温度,在CeO2含量为3％的样品中,堇青石的峰最明显,但是过量的氧化铈会抑制了堇青石的生成;随着CeO2加入量的增加,其气孔率和弯曲强度也会随之变化,1200℃下,在CeO2加入量为4％时其弯曲强度最优.但随着CeO2的含量的增加,其气孔率逐渐下降.     

钛酸铝多孔陶瓷的研制

本文探讨了成孔剂和烧结温度对钛酸铝多孔陶瓷性能的影响，研究表明，不同成孔剂对显气孔率的影响不同，成孔剂含量提高，显气孔率增加。但不宜过量，烧结温度上升，强度和化学稳定性提高，显气孔率和热膨胀系数下降。     

多孔低介电氧化硅陶瓷材料的制备

采用氧化硅为原料,木屑作为造孔剂制备了多孔的氧化硅陶瓷材料。借助于气孔率测试、抗弯强度测试、介电性能测试和SEM测试手段分析了造孔剂和烧结助剂的添加量对材料性能的影响。结果表明:加入BN作为添加剂烧成的氧化硅抗弯强度最大可达到14.80MPa。加入木屑作为造孔剂制备的陶瓷可以形成明显的气孔,气孔率最高可达到48.40%,介电常数最低可以达到3.0。     

Fabrication and Evaluation of Porous Piezoelectric Ceramics and Porosity–Graded Piezoelectric Actuators

Porous ceramics of lead zirconate titanate (PZT) were prepared by sintering powder compacts consisting of PZT and stearic acid powders in an air atmosphere; stearic acid was added as a pore-forming agent (PFA). The dielectric, elastic and piezoelectric properties of uniformly porous PZT ceramics were investigated as a function of the porosity volume fraction. Furthermore, a beam-shaped PZT actuator sample with a graded porosity content across its thickness was fabricated by sintering PFA-graded powder compacts. The electric-field-induced bending displacement characteristics of the actuator samples were measured by using strain gauges and were found to be in good agreement with the theoretical predication based on a classical lamination theory.     

鳞片石墨对无粘结剂炭材料性能的影响

：采用煤沥青中加入一定量鳞片石墨制备的类中间相原料,再经过成型、烧结等工艺制备无粘结剂炭材料。实验表明：在类中间相原料制备过程中加入一定量鳞片石墨,所制得的无粘结剂炭材料的电阻率相对传统无粘结剂炭材料有所下降,其抗折强度是传统炭材料的3倍左右。当鳞片石墨质量分数为沥青的6％时,所制备的无粘结剂炭材料的体积密度为1．46g／cm^3,电阻率为46．0μ·Ω,抗折强度为29．8MPa。     

不同造孔剂对煤矸石合成多孔莫来石性能影响的研究

以煤矸石为主要原料,高铝矾土熟料为调配成分,选取不同种类的造孔剂,通过模压成型的工艺,在1200℃下烧结制备多孔莫来石材料。通过TG-DTA、阿基米德法、XRD和SEM等检测手段,对制品的显气孔率、体积密度、力学性能和微观结构等进行研究。结果表明:在1200℃合成主晶相为莫来石的多孔莫来石材料;造孔剂的种类和粒径不同,造孔效果不同;随着造孔剂含量的增加,显气孔率增大,体积密度和抗折强度呈下降趋势。     

Characterisation of porous PZT ceramics by first-order reversal curves (FORC) diagrams

The method of investigation based on the first-order reversal curves (FORC) is proposed for describing the role of porosity on the switching properties of Nb–PZT ceramics with anisotropic porosity prepared using lamellar graphite as pore-forming agent. The experimental FORC diagrams have two distinct parts attributed to the reversible and irreversible components of the ferroelectric polarization. A more localized distribution was found in the dense material, while in the porous one (40% porosity) the distribution is broad and spread towards higher fields, due to the local depolarising field created at the boundaries. The FORC susceptibilities indicate the degree of tunability of the permittivity under the applied field. In this analysis it was found that porosity has a detrimental effect on the tunability of the system in the same range of the electrical fields.     

New Uniformly Porous CaZrO3/MgO Composites with Three-Dimensional Network Structure from Natural Dolomite

Porous CaZrO₃/MgO composites with a uniform three-dimensional (3-D) network structure have been successfully synthesized using reactive sintering of highly pure mixtures of natural dolomite (CaMg(CO₃)₂) and synthesized zirconia powders with LiF additive. Equimolar dolomite and zirconia powders doped with 0.5 wt% LiF were cold isostatically pressed at 200 MPa and sintered at 1100–1400°C for 2 h in air. Through the liquid formation via LiF doping, strong necks were formed between constituent particles before completion of the pyrolysis of dolomite, resulting in the formation of a 3-D network structure. During and after the formation of the network structure, CO₂ was given off to form a homogeneous open-pore structure. The pore-size distribution was very narrow (with pore size ∼ 1 μm), and the porosity was controllable (e.g., ∼30%–50%) by changing the sintering temperature. The porous composites can be applied as filter materials with good structural stability at high temperatures.