有机添加剂对ZrO2流延生坯性能的影响

有机添加剂是流延料浆的关键组元,它们对料浆和流延生坯的性能有很大的影响.文章用流延法制备了YSZ电解质薄膜,并对生坯的力学性能进行了研究,分析了各有机添加剂对生坯力学性能的影响,最终提出了提高生坯及烧结体质量的方法.     

陶瓷材料流延成型研究现状

简要概括了陶瓷坯体流延成型的工艺过程,比较了水基流延成型与传统流延成型技术相比的优点和不足之处,着重介绍了陶瓷材料新型流延成型工艺的研究现状,并指出了陶瓷坯体水基流延成型工艺的发展方向。     

Mo-(Fe-B)-Fe混合粉末流延成型薄层坯体的干燥机理分析

流延成型Mo-(Fe-B)-Fe混合粉末流延成型薄层坯体的干燥过程非常重要，本文根据现有理论对流延坯体干燥过程的各个阶段，特别是坯体孔隙中充满液相的恒速干燥阶段（CRP）进行了分析。在恒速干燥阶段，产生了坯体的最大收缩和最大干燥应力，对引起干燥收缩的力和液相传输机制进行了分析。通过分析液相流动和固体网络之间的相互作用。可以计算孔隙液相中的压力分布。在靠近坯体干燥表面处，液相压力具有最大值，导致坯体在该处承受较大的压应力，并由此产生了不同大小的坯体收缩，从而引起干燥过程中的开裂现象，坯体开裂的可能性主要与坯体厚度和干燥速率有关，提出了避免干燥开裂的几个技术措施。     

BaTiO3瓷粉水基流延成型的研究

本文以BaTiO3瓷粉为原料，聚丙烯酸酯类水性粘合剂为载体，通过水基流延成型成功制备了20-25μm的电子陶瓷素坯膜；研究了水性粘合剂对浆料的流变性、流延素坯膜的力学性能及微观结构的影响。结果表明，水性粘合剂的用量为10％时，流延素坯膜的综合性能较好．BaTiO3在粘合剂中分散均匀。     

表面改性对蛭石流延浆料性能的影响

蛭石是一种具有层状硅酸盐结构的非金属矿物,具有良好的抗氧化性和压缩回弹性,是制备耐高温密封材料的优质原料.论文采用流延法进行材料成型加工,以硬脂酸和硅烷偶联剂A-151为改性剂,考察表面改性对蛭石流延浆料分散稳定性和流变性能的影响.结果表明,硬脂酸改性效果优于硅烷偶联剂A-151,当硬脂酸用量为2％时,高温膨胀蛭石粉体接触角为83°,改性效果显著,球磨制浆的RSH最大为79.2％,分散稳定性较好,浆料流动性最佳,流延坯带表面平整、均匀.     

固相含量对氧化锆陶瓷注凝成型的影响

研究了超细ZrO2粉体注凝成型过程中固相含量对料浆粘度、生坯强度和烧结材料密度等的影响。在固相含量50vol%~54vol%的范围内,随着固相量的增加,料浆悬浮体的粘度明显提高,成型坯体的均匀性下降,生坯强度出现极值,烧结材料的密度逐渐降低,固相含量以50vol%~52vol%为宜。     

99氧化铝陶瓷基板注凝成形工艺的研究

以注塑成型技术为基础，研究99氧化铝陶瓷基板的制备工艺，实验研究了影响料浆性能及坯体均匀性的因素，确定了合理的制备工艺参数。     

分散剂对ZrO2料浆及陶瓷性能的影响

分散剂是流延料浆中的关键组元.本文选用了3种分散剂(三乙醇胺、磷酸三丁酯、松油醇),通过对分散剂用量、pH值对ZrO2料浆性能的影响、素坯及烧结体密度、气孔率和收缩率等方面的研究,分析比较了分散剂对料浆及陶瓷性能的作用.实验结果表明:pH在10～12.5内,三乙醇胺对ZrO2粉体的分散用量少、料浆稳定,适于制备气孔少,致密度高的ZrO2固体电解质薄片.     

硅酸锆凝胶注模成型工艺的研究

主要以降低ZrSiO4陶瓷浆料的粘度和提高固相含量为目的,利用正交实验研究了硅酸锆陶瓷凝胶注模成型工艺中固相含量、pH值和分散剂3个因素对料浆粘度的影响,并根据实验结果拟合出回归方程;同时通过电镜分析了坯体微观形貌的差异,制备出固相体积含量55%、粘度0.57Pa·s的硅酸锆陶瓷浆体,所得坯体微观结构均匀、团聚少.     

注浆成型“水流方向、速度”与“坯体”

注浆成型方法是陶瓷生产中坯体制造的基本方法之一。即采用多孔性(微孔)材料制成模型,然后把制好的料浆注入模型中,依靠模型材料的微孔不断吸入料浆中的水份,使模体内的料浆逐渐失去水份而硬化形成坯体。     

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.     

Particle Orientation During Tape Casting in the Fabrication of Grain-Oriented Bismuth Titanate

Slurries containing platelike Bi₄Ti₃O₁₂ particles have been tape cast to prepare green sheets with aligned particles. The slurries contain well-dispersed particles and show nearly Newtonian flow behavior. The effect of slurry composition and casting conditions on the particle orientation has been examined. The particle orientation in the green sheet is determined mainly by powder content; other parameters, such as binder content, casting speed, and blade opening, have little effect. The interaction between particles is a main cause for particle alingnment. The slurry with a large powder content is favorable for preparing dense grain-oriented ceramics.     

Effect of medium condition change on green body density during casting and drying

The present study examined whether the optimum slurry conditions in which the green body with the highest packing fraction was fabricated were the same regardless of whether tape or slip casting methods were used. Additionally, we investigated the optimum slurry evaluation method to predict the packing fraction of each green body. Specifically, aqueous dense alumina slurries, whose particle dispersion state was changed by varying pH and the amount of dispersant additive, were prepared. After changing the pH, the optimum slurry conditions were achieved regardless of the casting method. The most suitable amount of additive dispersant differed due to the changing solution conditions during the casting and drying process; the medium of the slurry permeated into the plaster during slip casting and dried on the substrate during tape casting. Thus, in slip casting, non-adsorbed polymers could also be permeated. Hence, it is crucial for slurry evaluation to predict the packing fraction of the slip cast body. A sedimentation test, which involved particle condensation as well as casting, was valid for the green sheet. Conversely, it was experimentally shown that the constant pressure filtration test, which involved the permeation of the medium in addition to particle condensation, was suitable for slip casting.     

The tape casting process for manufacturing low‐temperature co‐fired ceramic green sheets: A review

For low‐temperature co‐fired ceramic technology, the fabrication of high‐performance green sheet is a critical step because of its effect on subsequent operations such as punching, printing, laminating, and firing. Here, we present an overview of the tape casting process for manufacturing high‐performance low‐temperature co‐fired ceramic green sheets. Previous research is reviewed, and the primary materials for preparing the casting slurry, such as powders, solvents, dispersants, binders, and plasticizers, are systematically described. Their functions, application methods, and action mechanisms are described. Suggestions are made for future research into the tape casting process based on recent results.     

Application of polypropylene carbonate for the tape casting of silicon nitride ceramics

QPAC40 (polypropylene carbonate), with a little decomposition residue, is commonly used as a binder in aluminum nitride (AlN) tape casting. In this paper, we tried to explore its application in silicon nitride (Si₃N₄) tape casting. By studying the influence of dispersant, binder, plasticizer/binder ratio, and solid loading on slurry and green tape properties, the optimum formulation of the tape casting of Si₃N₄ slurry was determined, and the green tape with a uniform structure and relative density up to 63.16% was prepared. Si₃N₄ ceramics were obtained by debinding at 600°C for 1 h in vacuum and gas-pressure sintering at 1830°C for 2 h in N₂. The thermal conductivity and flexural strength of Si₃N₄ ceramics were 56.28 ± 1.21 W/(m·K) and 1130.67 ± 23.58 MPa, respectively. These results indicated that QPAC40 can be used to prepare Si₃N₄ sheets through tape casting.     

流延成型法制备Mn掺杂Ba_(0.6)Sr_(0.4)TiO_3/MgO陶瓷及其介电性能

用流延成型法制备Mn掺杂钛酸锶钡(BaxSr1-xTiO3,BST)/MgO复相陶瓷厚膜,介绍从制粉、流延浆料制备到厚膜的脱脂及烧结的整个工艺流程。通过差热-热重测试曲线分析Mn掺杂BST/MgO流延膜的脱脂特性,制定膜片的脱脂工艺。用扫描电镜观察不同温度烧结样品的微观结构,确定最佳厚膜烧结工艺,在1320℃和1350℃烧结的陶瓷厚膜样品的相对密度达到96.1%。分析研究不同温度烧结陶瓷厚膜的介电性能的结果表明:1350℃烧结样品的室温相对介电常数为108,介电损耗低于0.002,Curie温度在-70℃左右,介电常数可调率为25.15%。     

Preparation and electrical properties of multilayer ZnO varistors with water-based tape casting

Multilayer ZnO varistors were prepared by water-based tape casting with water-soluble acrylic as binders. Zeta potentials of the doped ZnO suspensions as a function of pH with and without dispersant were measured. Viscosity measurements were used to find the optimum dispersant concentration needed to prepare a stable slurry. Viscosity properties of the tape casting slurry were investigated. The results showed that aqueous acrylic binders have shear thinning properties suitable for tape casting of ceramic powders. Scanning electron microscopy (SEM) studies revealed that the green sheets have a smooth defect-free surface and that the multilayer varistor (MLV) ceramics prepared by water-based tape casting have a fine grain microstructure with a uniform grain size and dopant distribution. The multilayer ZnO varistors prepared by water-based tape casting display comparable good electrical properties to those prepared by solvent-based tape casting. This is believed to be attributed to the well dispersed water-based slurry, which makes more uniform dopant distribution throughout the multilayer ZnO varistors. Therefore, water-based tape casting is suitable for the manufacture of high performance multilayer ZnO varistors.     

The preparation of SiCP/Ag–Cu–Ti hybrid tapes and application in the joining of silicon carbide ceramics

Abstract

A novel method of tape casting to fabricate ceramic-particulate-reinforced composite filler alloy tapes with low organics (no more than 6?wt.%) was developed, with which SiC_P/Ag–Cu–Ti hybrid tapes were successfully prepared and used in joining of sintered silicon carbide ceramics. The stress rheometer, scanning electron microscopy and energy dispersive spectrometer were used to characterize the rheological properties of slurry and microstructure of green tapes and joints. The slurry for tape casting consists of dispersant, binder, solvent, a mixture of ceramics particulates and metal powders, and no plasticizer was added. Castor oil phosphate was proven the suitable dispersant for the slurry, and the content of dispersant, binder, solid loading was optimized as 3?wt.%, 2.6?wt.% and 26?vol.%, respectively. The fabricated hybrid tapes possess good ductility and uniform thickness. The SiC particulates were homogeneously distributed in the metal powders matrix in both sides of the green tapes, and the distribution was retained in the SiC/SiC joints.     

水基流延工艺制备陶瓷材料的研究

流延法作为制备片层材料的重要工艺已经被陶瓷研究者广泛应用.但是,有机流延体系带来的环境污染、毒性及易燃性等问题已被社会所关注.因此,研究无毒、无污染的水基流延工艺已得到材料界的广泛重视.本文主要概述了国内外水基流延工艺的研究现状,重点介绍了PVA体系、丙烯酰胺凝胶流延体系、纤维素类粘结剂体系及乳胶体系的不同特点;从粘结剂、分散剂、增塑剂等多个角度分析了影响水基流延工艺的技术因素,并提出了很好的解决方法,最后介绍了乳胶体系水基流延工艺在制备片状或层状陶瓷材料方面的应用.