纳米氧化锆粉体流变性能的研究

本文通过Ｚｅｔａ电位和流变性能的测量,研究了ｐＨ值及聚合物电解质对纳米Ｙ－ＴＺＰ粉体浆料分散的影响。结果表明,Ｙ－ＴＺＰ的Ｚｅｔａ曲线呈正弦波形式,在等电点乐料易产生聚沉,在强酸强碱性条件下也不利于浆料的分散。综合考虑Ｚｅｔａ电位,沉降高度及粘度等流变行为,认为高Ｚｅｔａ电位是获得稳定浆料的必要条件,加入Ｄａｒｖａｎ Ｃ（聚甲基丙烯酸氨）可显著提高浆料的Ｚｅｔａ电位及碱性条件下的稳定性,通过运用静     

纳米氧化锆粉体流变性能的研究

本文通过Ｚｅｔａ电位和流变性能的测量,研究了ｐＨ值及聚合物电解质对纳米Ｙ－ＴＺＰ粉体浆料分散的影响。结果表明,Ｙ－ＴＺＰ的Ｚｅｔａ曲线呈正弦波形式,在等电点附近,浆料易产生聚沉,在强酸强碱性条件下也不利于浆料的分散。综合考虑Ｚｅｔａ电位、沉降高度及粘度等流变行为,认为高Ｚｅｔａ电位是获得稳定浆料的必要条件,加入ＤａｒｖａｎＣ（聚甲基丙烯酸氨）可显著提高浆料的Ｚｅｔａ电位及碱性条件下的稳定性,通过运用静电位阻稳定机理,可获得分散良好的浆料。     

利用声波粒度仪研究Mg~(2 )在Al_2O_3表面的特性吸附

利用声波粒度仪、Ｚｅｔａ电位仪详细研究了金属镁离子在氧化铝粉体表面的特性吸附行为．发现Ｍｇ２＋浓度、体系ｐＨ以及浆料的固体含量都对氧化铝颗粒表面的Ｚｅｔａ电位有显著影响,在不同的实验条件下引起粉体颗粒表面电荷的反转或等电点的位移．不同ｐＨ条件下的粒度测量结果所反映的体系稳定性与Ｚｅｔａ电位较好的吻合．首次用ＡＦＭ证实了特性吸附条件下,氧化物表面水化层的存在．     

含镁离子电解质对氧化铝浆料流变性能的影响

通过高纯氧化铝陶瓷浆料粘度和zeta(ζ)电位等参数的考察,探讨了不同pH值下,含镁离子电解质对其流变性能的影响。结果表明,镁离子会降低氧化铝浆料的流变性能。在其存在下,无分散剂时与添加聚丙烯酸(PAA)作分散剂时,pH值分别为6.5和9.5的浆料具有良好的流变性能。无镁离子存在时,PAA的最佳添加量为0.5%;镁离子浓度为0.05mol/L时,该量增加至0.9%。     

高温氢传感器固体电解质管的浆料流变性及低压注射成型

作为质子导体的CaZr0.9In0.1O3-α(CZI10)浆料注射成型是制备管状固体电解质的有效方法。通过测试低压注射成型(LPIM)浆料的粘度并计算出流变特征参数,分析了剪切速率、温度和固体体积分数对浆料成型性能的影响,并对由最优浆料制备的固体电解质管组装的氢传感器性能进行了研究。实验结果表明:在70~90℃条件下,浆料在3~50s^-1剪切速率范围内为假塑性流体,表现出剪切稀化现象,温度越高剪切敏感系数越小,浆料粘度也越小。浆料的相对粘度与固体体积分数关系符合Quemada模型。温度越高、固体体积分数越低时浆料的成型指数越大。固体体积分数为56.4vol.%的浆料具有最小的剪切敏感系数和流动激活能,最适合固体电解质管的成型。该浆料在80℃成型并经脱脂和烧结后制得的固体电解质管质量分布均匀、无成型缺陷。用固体电解质管组装的氢传感器在750℃时对0.5~10vol.%不同氢气浓度气体的响应电动势与氢气浓度对数呈线性关系。     

固体高分子凝胶电解质：Ⅰ.交联聚醚高分子凝胶电解质

研究了由交联聚醚－锂盐－极性有机化合物三元组分组成的固体高分子凝胶电解质的组成结构对其离子导电性能的影响，结果表明，极性有机化合物在三元组分体系中同时起到了增塑作用和升高体系介电常数的作用，这两种作用都有利于提高这种体系的离子导电性能。固体高分子凝胶电解质中所含的有机化合物组分的粘度愈低，或介电常数愈高，它的离子电导率愈高。与具有相同结构高分子基体的高分子固体电解质比较，固体高分子凝胶电解质的离子     

氧化铝陶瓷直接凝固注模成型(DCC)工艺参数的研究

直接凝固注模成型(DCC)是利用陶瓷浆料粘度变化制备陶瓷坯体的先进成型方法,脱模时间长是限制其应用的主要问题.通过调整DCC工艺参数,减小充模前浆料的粘度以利于成形,而在充模后使浆料的粘度迅速增加,缩短脱模时间.将高固含量(体积分数为70%)低粘度的陶瓷浆料浇注到模具中,通过改变浆料的pH值或浆料离子浓度来改变其胶体化学行为,调节浆料流动性能;通过温度控制加速浆料凝固,使充模后10 min的浆料粘度与充模前浆料粘度比值达到13,3倍于传统浆料成型方法,充模后1 h即可得到有足够脱模强度的陶瓷坯体,效率显著提高.     

固体高分子凝胶电解质I．交联聚醚高分子凝胶电解质

研究了由交联聚醚－锂盐－极性有机化合物三元组分组成的固体高分子凝胶电解质的组成结构对其离子导电性能的影响，结果表明，极性有机化合物在三元组分体系中同时起到了增塑作用和升高体系介电常数的作用，这两种作用都有利于提高这种体系的离子导电性能。固体高分子凝胶电解质中所含的有机化合物组分的粘度愈低，或介电常数愈高，它的离子电导率愈高。与具有相同结构高分子基体的高分子固体电解质比较，固体高分子凝胶电解质的离子电导率可高出２～３个数量级以上。     

层状磷酸锆和氧化锆粉体对染料敏化太阳电池电解质性能的影响

利用合成的层状结构的α-ZrP和球形ZrO2颗粒添加到液态电解质中,获得了改善的界面电荷传输特性和离子传输性能。二者在约3%(质量分数)时得到最好的效果。对于颗粒加入对电解质性能的影响进行了分析,认为主要是颗粒表面特性和离子浓度增加带来的Grothus增强机制改善了电解质电化学特性。     

NiO-YSZ-石墨水系浆料的研制及其在注浆成型制备固体氧化物燃料电池中的应用

Ni-YSZ(钇稳定氧化锆)金属陶瓷普遍被用作固体氧化物燃料电池(SOFC)的阳极材料,其氧化物浆料的性质对湿法制备的SOFC的性能具有重要影响。通过zeta电位分析,研究了NiO-YSZ双分散相水系浆料的稳定性。对六种分散剂作用于NiO、YSZ表面的zeta电位进行研究,发现采用的阴离子分散剂和两性分散剂使NiO和YSZ在水中带有相反电荷而引起迅速絮凝;采用阳离子分散剂聚二烯二甲基氯化铵(PDAC)时,NiO和YSZ因带有正电荷相互排斥而稳定分散于水中,在此基础上,加入作为SOFC阳极造孔剂的石墨,采用聚乙烯吡咯烷酮(PVP)作为石墨的分散剂,制备出了NiO-YSZ-石墨的稳定水系浆料。采用此浆料通过注浆成型制得阳极支撑管,进而组装成SOFC单电池。该单电池在800℃时最大功率密度达到509 mW。cm~(-2);扫描电镜(SEM)分析表明电极与电解质间接触良好,阳极孔洞分布均匀。     

The effects of salt concentration on ion state and conductivity in comb cross-linked polymer electrolytes

A new type of comb cross-linked polyurethane/acrylate polymer was designed. The polymer has sparse network structure with many long comb molecule chains. A new solid polymer electrolyte (SPE) was prepared based on the polymer. The salt in the solid polymer electrolytes has different existent states with different salt contents. With increase of salt concentration, the ion pairing gradually becomes important existent form of salt, and T _g value of the SPE increases. At the same time, ionic conductivity increases rapidly. It is possible to design novel solid polymer electrolytes with high ionic conductivity to meet practical application by comb cross-linked polymer with high salt content.     

Rheology Study of Suspension Formed by Different Nano-size Y-TZP

The rheological properties of slurries formed by different nano-size Y-TZP have been studied.The viscosity is sensitive to solid loading especially for high solid content level. The dispersant NH4PAA can improve the flowability efficiently. The smaller ceramic particles need to adsorb more dispersant to the flowability. Under the same solid content, the smaller the particles, the higher the viscosity of its slurry     

聚甲基丙烯酸多缩乙二醇二酯－锂盐－增塑剂聚合物电解质的离子电导

合成了一系列甲基丙烯酸多缩乙二醇二酯（ＰＥＤ），并且考察了溶剂含量、盐浓度、增塑剂种类对由ＰＥＤ、锂盐、溶剂组成的聚合物电解质的电导率的影响。当溶剂含量局于８０ｍｏｌ％，盐含量相同时，不同分子量的ＰＥＤ形成的电解质的电导率非常接近，表明增塑剂在盐的解离和离子迁移过程中起主导作用。研究了四种增塑剂：碳酸乙烯酯（ＥＣ）、碳酸丙烯酯（ＰＣ）、四乙二醇（ＴＥＧ）和ＰＥＧ＿（４００），发现其增塑效果同它们的介电常数大小的顺序相吻合。对于室温电导率，在ＬｉＣＬＯ＿４盐浓度为０．９ｍｏｌ／１时，存在最大值。但当温度上升时，电导率对盐浓度的依赖性发生了改变，通过离子－离子对－三离子之间的平衡随温度的变化可以很好地解释该种现象。本文还研究了电导率的温度依赖性，发现在盐浓度低于０．５ｍｏｌ／ｌ时，符合阿仑尼乌斯关系。     

Influence of polyelectrolyte dispersant on slip preparation of nano-sized tetragonal polycrystals zirconia for aqueous-gel-tape-casting process

In this work, the conditions for the preparation of stable nanometer zirconia slurries with high solids content for the production of aqueous-gel-tape-casting objects with improved properties are identified. Influences of the powder and dispersant on the rheological properties were investigated. The result indicated the polyelectrolyte dispersant greatly affected the surface charge of nanometer tetragonal zirconia powder and the rheological behavior of nanoparticles zirconia’s suspensions. For each factor there exists an optimum range in which low viscosity was achieved for a slurry of high solid content. The proper content of the dispersant is between 0.8 and 1.2 wt.%. The rheology character of high solid loading slurries is non-Newtonian flow—‘shear-thinning’ character as the shear rate is increased. The viscosity of the 77 wt.% powder loading slurry with about 1.0 wt.% polyelectrolyte (based on the powder) was 0.35 Pa s at the shear rate of 110 s⁻¹. The slurry at the optimum conditions met the demands of aqueous-gel-tape-casting process.     

Electrochemical properties of solid polymer electrolytes prepared by the hard/soft acid base principle

In order to improve the electrochemical properties including ionic conductivity of SPEs (solid polymer electrolytes), understanding of the interaction between the polymer and salt in the SPE is important. In this study, four types of polymer matrices and four types of salts were used according to the hard/soft acid base (HSAB) principle. The results of impedance measurement reveal that the ionic conductivities are affected by the HSAB principle at low salt concentration. With increasing salt content, however, the SPEs are influenced by the ion hopping property of salt rather than by the solubility of the polymer with salt. In contrast, the PPS-based SPE shows different characteristics because it is prepared as a slurry phase at high salt content.     

DMAA凝胶体系凝胶注模成型超细ZrO2陶瓷

为了降低传统丙烯酰胺(AM)/N,N-亚甲基双丙烯酰胺(MBAM)凝胶体系的毒性,制备高固相量、低粘度的超细ZrO2(D50=0.19μm)浆料及高性能的生坯和陶瓷,研究了低毒的N,N-二甲基丙烯酰胺(DMAA)/MBAM凝胶固化工艺及pH值和聚甲基丙烯酸铵(NH4PMAA)分散剂对浆料流变性的影响.最终采用低粘度、高固相量、低毒性的浆料制备了性能优异的生坯和陶瓷.浆料的固相量高达56vol%,生坯表面光洁、不起皮、不开裂,强度接近30MPa,其内部颗粒结合紧密,孔径呈单峰分布,ZrO2陶瓷的抗弯强度及断裂韧性分别为960MPa和17.3MPa m1/2,其结构均匀、致密性好、四方相ZrO2含量高.     

聚(丙烯酸-丙烯酰胺)-碱金属盐复合物的离子电导性

聚（丙烯酸－丙烯酰胺）－碱金属盐复合物是一种新型高分子固体电解质。文中详细讨论了离子种类，盐浓度，增塑剂种类和用量以及温度等因素对其电导率的影响。结果表明，不同碱金属盐对电解质电导率的影响因其阳离子半径，晶格能，离子淌度以及在电解质中的溶解度的不同而不同。     

电化学氧化对高强高模碳纤维表面结构及力学性能的影响

利用循环伏安多重扫描法分析了不同电解质的氧化能力及其氧化特点,讨论了在表面氧化处理中不同电解液体系对高模高强碳纤维力学性能的影响,提出了适合高强高模碳纤维表面处理的工艺条件,并通过Raman光谱、XPS与SEM的表征,研究了电化学氧化对高强高模碳纤维表面结构及力学性能的影响。研究结果表明,与NH₄H₂PO₄溶液相比,用NH₄H₂PO₄与CH₃COONH₄复合的电解质溶液对碳纤维进行表面处理,能大幅度提高纤维表面含氧官能团,而且纤维表面sp²杂化碳原子相对含量也较多,在提高了碳纤维/环氧树脂复合材料层间剪切强度(ILSS)的同时,还较好地保持了高强高模碳纤维本体力学性能。当CH₃COONH₄与NH₄H₂PO₄的物质的量之比为2:1时,碳纤维/环氧树脂复合材料的ILSS与未处理纤维相比提高了168%,而碳纤维拉伸强度却下降很小,此复合电解质溶液是一种较为理想的对高强高模碳纤维进行表面改性的电解质体系。     

Electronic conductivity of a ZrO2 thin film as an oxygen sensor

The ionic conductivity and sensitivity of a series of Ce⁴⁺-doped zirconia thin films synthesized by the sol-gel process are studied. The conductivity of the film is mainly dependent on the doping ions and its concentration. The results show that the ZrO₂(Ce⁴⁺) solid solution is well suited to maintain the ionic conductivity in a wide composition range. A physical model is proposed to explain the high sensitivity of the thin film.     

Characterisation of Ce0.8Gd0.2O1.9/3Y-TZP composite electrolytes—effects of weight % 3Y-TZP particles

Solid oxide fuel cell electrolytes are currently manufactured from zirconia. This is due to its high ionic conductivity and mechanical strength. However, a disadvantage of zirconia is the high temperatures required for efficient operation, greater than 900°C for cells not utilising thin supported electrolytes. A study to characterise the properties of an alternative composite solid electrolyte, based on a gadolinia doped ceria matrix surrounding yttria stabilised tetragonal zirconia particles is presented. Composite samples produced using 1, 2, 5, 10 and 20 wt% zirconia particles were characterised using a range of different experimental techniques including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, mechanical testing and impedance spectroscopy. Results showed a lowering in flexure strength of the experimental composite samples with the addition of particles. It is considered that the particles acted as regions where cracks could initiate.