流延法制备8YSZ薄膜

采用非水基流延法制备了8mol%氧化钇稳定氧化锆薄膜,研究了球磨时间、固含量、有机添加剂含量及除泡工艺对8YSZ浆料流变性能的影响,通过SEM表征烧结体表面形貌,用电化学阻抗仪对烧结体进行电导率测试。结果表明:分散剂用量1.25wt%,球磨时间15h,浆料的粘度最小,分散效果最好;增塑剂与粘结剂比例为0.7,粘结剂加入量6.5～8.5wt%,二次球磨后,真空除泡可获得适合流延的浆料;生坯1450℃烧结4h,烧结体晶界清晰、致密度较好;烧结体在300～800℃随温度的升高电导率逐渐增大,在800℃时离子电导率达0.046S/cm。     

水基凝胶注模法YSZ陶瓷浆料性能的研究

利用3种分散剂研究了凝胶注模用YSZ浆料的流变性。通过测量Zeta电位,沉降试验、料浆粘度和不同球磨时间分别观察粉体的分散行为,实验表明:分散剂DA分散效果最佳,固相体积分数为53%时粘度仅为690mPa·s,PN1124次之,MN最差;53%料浆球磨25h粘度最低。     

多孔NiO/钇稳定氧化锆陶瓷的水系流延成型

采用水系流延工艺制备了阳极支撑型固体氧化物燃料电池的阳极材料NiO/钇稳定氧化锆(yttria-stabilized zirconia,YSZ)陶瓷.研究了分散剂聚丙烯酸(polyacrylic acid,PAA)和pH值对YSZ和NiO颗粒的zeta电位以及65% (质量分数,下同) NiO/35% YSZ浆料黏度的影响.结果表明:在pH=9.6和加入分散剂时,NiO和YSZ颗粒的zeta电位绝对值达到最大值;当PAA的含量为NiO/YSZ粉料的0.8%时,NiO/YSZ浆料黏度最小.浆料中添加石墨粉作为造孔剂能提高阳极材料的孔隙率.石墨粉在聚乙烯吡咯烷酮的作用下均匀分布在阳极烧结体中.石墨粉的含量对阳极烧结体中的开口孔隙率有重要的影响,在石墨粉的含量为25%,阳极烧结体的孔隙中的开口孔隙率占全部孔隙率的98%.     

PMN-PZT压电陶瓷的凝胶注模研究

对三元系PMN—PZT压电陶瓷的凝胶注模成形工艺进行了研究,重点讨论了分散剂加入量、pH值、球磨时间与注模浆料流变之间的关系,当分散剂用量为0 .95 %～1 .0 5 % ,pH值为10 .5～11 .5 ,球磨时间为8h时,可以制备出固相含量为5 5 % ,粘度小于1Pa·s的PMN -PZT压电陶瓷悬浮体。将凝胶注模与传统模压成形工艺制备的样品进行了比较,通过扫描电镜(SEM )显微形貌分析和电学性能测定。结果表明:凝胶注模工艺制备的样品与模压工艺制备的样品相比较,其显微结构均匀致密、晶粒大小与晶界分布均匀,气孔率更小,电学性能更均匀。     

莫来石泡沫陶瓷浆料性能研究

以自制莫来石(粒度为0.045~0.075 mm)、高岭土(粒度为0.045~0.088 mm)和磷酸为主要原料,采用有机泡沫浸渍法制备泡沫陶瓷过滤材料,研究了球磨时间和固相含量对泡沫陶瓷浆料粘度、稳定性、颗粒粒径等性能的影响,并对其机理进行分析。采用XRD、SEM、EDS等手段研究了泡沫陶瓷的性能、物相及显微形貌。结果表明:通过配制固相含量为60%~62%的浆料、球磨8h,可以制备出沉降度较低,粘度适宜,莫来石颗粒D_(50)较小,适合浸渍的优质浆料;将浆料均匀涂覆在有机泡沫基体上,在1450℃烧结2.5h可以得到抗压强度高达1.59MPa,抗热震性13次,开孔率86%的泡沫陶瓷产品。     

基于原料选控的氧化铝水基凝胶成型工艺分析

随着结构陶瓷各种新型胶态成型工艺的发展，精密复杂陶瓷件的制备对其原料粉体提出了越来越高的要求。国际高纯氧化铝原料市场主要由日、法两国占有，国内生产厂家良莠不齐。本文首先通过干压成型烧结试验，从12个批次的国产氧化铝粉体中筛选了烧结活性较高的原料。选用异丁烯/马来酸酐共聚物（Isobam）作为粘结剂，通过调整浆料分散剂体系，控制固含量和粘度，筛选出4种适用于凝胶注模的原料粉体。比较了凝胶注模样品与干压样品的性能差异。配置出了固含量达到50vol%的低粘度凝胶注模浆料，并在1650℃烧结3 h的条件下，得到了致密度97.3%、弯曲强度236 MPa的氧化铝异型陶瓷。     

高固含量氧化铝浆料流变性的关键因素研究

制备高固含量、低粘度的浆料是原位固化成型的关键。本工作研究了搅拌磨转速与时间等工艺参数对氧化铝浆料粘度的影响。结果表明,在75 rpm 和 150 rpm 低转速下,浆料的粘度随球磨时间的延长而逐渐减小;而在300 rpm高转速下,浆料粘度出现先减小后增加的现象。通过研究分散剂类型、分散剂加入量、浆料固含量、粉体种类等因素对粘度的影响规律,发现粉体中镁离子是导致浆料高速搅拌球磨后粘度增大的主要原因。该结果对制备高固含量低粘度的陶瓷浆料,尤其是对浆料制备涉及粉体含杂质和添加烧结助剂具有指导意义。     

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。     

ZrB2-SiC复相陶瓷的制备及其性能的研究

以ZrB2和SiC粉为原料,采用Si3N4球为球磨介质,通过等静压成型及无压烧结制备了ZrB2-SiC复相陶瓷。实验确定了ZrB2-SiC复相陶瓷的烧结制度,并研究了SiC含量与球磨时间对ZrB2-SiC复相陶瓷体积密度的影响。结果表明:随着ZrB2球磨时间的增加,ZrB2颗粒粒径逐渐减小,复相陶瓷的体积密度逐渐增加;随着SiC含量的增加,复相陶瓷体积密度降低。ZrB2最佳球磨时间为6h,SiC最佳含量为20%,ZrB2-SiC20%(体积分数)复相陶瓷体积密度达到4.98g/cm3。     

注浆成型B_4C/SiC复相陶瓷的工艺及性能研究

碳化硅陶瓷注浆成型工艺中浆料的分散稳定性和烧结工艺对碳化硅陶瓷的性能至关重要。采用真空无压烧结,以α-SiC超细粉为原料,B_4C为烧结助剂,研究分散剂、粘结剂、烧结助剂、烧结温度及保温时间等因素对浆料流动性、烧结特性与显微结构的影响规律。研究结果表明:在固含量为70%的SiC浆料中添加0.5 wt%TMAH和0.4 wt%PF,浆料的剪切粘度为184.75 m Pa·s,静置48 h没有明显沉降,符合注浆要求。在烧结温度为2000℃保温60 min的条件下,样品获得最佳烧结密度为2.719 g/cm~3。     

Preparation of alumina by aqueous gelcasting

The alumina ceramic was prepared by aqueous gelcasting. The effects of zeta potentials, solid loading, dispersant content and milling time on the alumina suspension were studied systematically. The dispersant content has remarkable effects on the viscosity of the suspension. The appropriate dispersant concentration for alumina aqueous slurry with the solid loading of 55 vol.% is 0.6 wt.%. It can be seen that all suspensions (50–56 vol.% solid loading) exhibited a shear-thinning behavior and relatively low viscosity, which was suitable for casting. The degree of shear thinning and the viscosity at high shear rates increased with increasing volume fraction of solid. As the milling time prolongs, viscosity of the suspension decreases first, then the plateau appears and the average diameter keeps changeless. When the milling time was shorter than 20 h, the viscosity of slurries decreased gradually as the time of milling increased. After 20 h milling, the viscosity of the slurry tended to be consistent. Therefore, the ball milling time should be equal to or more than 20 h to obtain a stable suspension at equilibrium. The time available for casting the slurry (idle time) can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing temperature. Micrograph of the gelcast green body was homogeneous.     

Rheological properties of nanosized barium titanate prepared by HGRP for aqueous tape casting

The conditions for the preparation of stable nanosized barium titanate suspensions with high solids content for the production of aqueous tape casting are identified. The rheological behavior of colloidal barium titanate suspension with Ammonium polyacrylate (NH₄-PAA) as a dispersant to aid the powder dispersion has been investigated. Nanosized barium titanate powder was synthesized by a continuous high-gravity reactive preparation (HGRP) technique, and then annealed at 900 °C for 2 h. Measuring the zeta potential, the particle size distributions and ball-milling time, assessed the optimum conditions of the suspension with low viscosity and stability. An isoelectric point (IEP) at pH = 2.8 was found. Particle size distribution tests identified an optimum pH value about 10 and an optimum dispersant addition about 1.2 wt.% (based on the dry powder weight). As the ball-milling time was longer than 8 h, the amount NH₄-PAA adsorbed on the barium titanate reached to saturation. The maximum solid content attained during this work was 45 vol.% at pH of 10, with dispersant addition 1.2 wt.%. High green density value (up to ∼55.4% of the theoretical density) in BaTiO₃ sheet was achieved with a solid content 40 vol.%. After sintering at 1200 °C for 2 h a final density of 95% is reached.     

PET/纳米SiO2复合材料的制备(Ⅱ):纳米SiO2在PET中的分散性研究

研究了分散方法、纳米材料的加入体系、分散时间、分散剂的种类及SiO2 的加入量对纳米SiO2 在PET/纳米SiO2 中分散性的影响 ,用TEM对其分散情况进行表征 ,并对其分散机理进行探讨与研究。其结果表明 :采用球磨分散法并以氨基硅烷A1 1 2 0分散剂时分散效果最佳 ;当分散时间达 7 5h时 ,分散液中SiO2 基本以纳米尺寸存在 ;将分散液加入对苯二甲酸二甲酯熔体中并在球磨状态下进行酯交换SiO2 的分散效果最好 ,1 0 0nm以下的SiO2 达 95 0 7% ;体系中随SiO2 量的增加 ,其分散性变差 ,当纳米SiO2 的加入量为 1 %～ 4 %时 ,粒径在 1 0 0nm以下的SiO2 由 88%下降到 61 %。     

燃烧法和固相法所制备的红褐色陶瓷颜料ZnFe1.2Cr0.8O4的研磨效果研究

本文以燃烧法和固相法分别制备的红褐色陶瓷颜料ZnFe_1.2Cr_0.8O₄(燃烧法：C-ZnF;固相法：S-ZnF)为研究对象,采用正交试验的方法对颜料颗粒的研磨最优参数进行分析探讨。使用激光粒度仪表征研磨前后颜料颗粒的粒度及其分布,通过极差分析法来分析研磨的最优参数。结果表明,上述两种颜料颗粒的最优研磨条件均为：添加5wt%的分散剂WF211,研磨时间为100min,研磨转速为2000rpm。在相同的研磨条件下,对比固相法制备的颜料颗粒S-ZnF,燃烧法制备的颜料颗粒C-ZnF可以得到颗粒粒度细且分布窄的颜料颗粒产品。另外,采用一种粒数衡算模型(PBM)来模拟颜料颗粒的研磨过程破碎行为,计算颜料颗粒在研磨过程中的选择函数矩阵。通过模拟分析表明,颜料颗粒C-ZnF的研磨效果要优于颜料颗粒S-ZnF。     

湿法纳米研磨制备药物纳米晶体——铝碳酸镁

低溶出速率和溶解度严重影响其生物利用度和药效, 是造成药物研发候选化合物不能成药的首要因素。近年的研究发现,当颗粒粒径减小到100～200nm,其溶出速率和溶解度会出现显著提升。本文研究了利用湿法纳米研磨技术制备铝碳酸镁药物纳米晶体的工艺。铝碳酸镁是治疗胃病的有效药物,其纳米颗粒悬浮液抗酸效果更好,起效速度更快。本文选择了六偏磷酸钠为分散剂,利用湿法研磨机,考察了分散剂用量、研磨转速、铝碳酸镁含量、研磨时间等参数对颗粒粒度分布的影响规律,获得了在最佳的工艺操作条件为研磨转速3000r/min、研磨时间105min、主药体积分数2%、分散剂为固含量质量分数的1.5%时,成功得到粒径D₁₀(76.4nm)、D₅₀(161nm)、D₉₀(352nm)的铝碳酸镁纳米悬浮液。制酸力实验结果证明纳米铝碳酸镁悬浮液比微米级悬浮液在盐酸中的溶出速率快5倍以上。     

Dispersion,rheology and aqueous tape casting of alumina–zirconia composites

Abstract

Alumina and zirconia were dispersed individually in aqueous media using Darvan C as the dispersant and at optimised pH condition. Based on sedimentation, rheology, yield stress, electrodeposition and zeta potential measurements, 2 wt-% of the dispersant and a pH of 10·5 were found to be the optimum condition for the codispersion of alumina and zirconia. Aqueous tape casting slurries with a solid loading of 32 wt-% were prepared under the optimised conditions of dispersion. Alumina–zirconia (50 : 50) composite tapes of 40 μm thickness and 56% green density were obtained.     

Tape casting of nanocrystalline ceria gadolinia powder

A ceramic ceria gadolinia solid solution membrane for solid oxide fuel cells was fabricated by tape casting using a nanopowder of 37 nm average particle size. A novel combination of solvent and dispersant was used to disperse the nanoparticles. The polymer was added in a dilute stage to guarantee a homogeneous distribution. After casting a remarkable densification of the cast tape suspension from a solid loading of 20 up to 42 vol.% was observed during drying. The green tape was sintered to >92% theoretical density and was dense towards perfusion. The resulting grain size in the sintered specimen still was <200 nm.     

乳液型ABS抗氧剂的研制

用高相对分子质量酚类主抗氧剂和具有碳自由基捕捉剂的辅助抗氧剂、表面活性剂、消泡剂、增稠剂与水通过研磨并加以复配的方法。研制出一种用于乳液聚合工艺生产ABS树脂的乳液型抗氧剂。由于该抗氧剂无需添加乳化剂即能均匀分散在丙烯腈／丁二烯／苯乙烯三元共聚物（ABS）胶乳中。在简化液体抗氧剂加入步骤的同时,改善了抗氧剂与胶乳的混合效果,使抗氧剂在ABS胶乳中的氧化诱导期延长约10％。乳液型ABS抗氧剂配方为：w（主抗氧剂A）22％;w（辅助抗氧剂B）11％;w（分散剂C）=3％：w（增稠剂D）1％;w（水）63％;w（消泡剂）为以上混合物料的0．05％。     

氮化硅流延膜的制备

流延成型是一种制备高质量陶瓷基片的成型方法.氮化硅是一种高热导率的材料,有望在电子基片领域获得应用.本文利用流延成型制备了具有较好柔韧性和一定强度的氮化硅流延素坯膜.研究了无水乙醇、无水乙醇/丁酮作为溶剂时对浆料粘度的影响.通过优化流延浆料添加剂的各种配比,得出了适合氮化硅粉体(SN-E10)流延的最佳配方.