流延法制备铌酸钾钠无铅压电陶瓷的工艺研究

以Na2CO3,K2CO3,Nb2O5等为原料,采用固相法合成了K0.5Na0.5NbO3的粉体,并以此粉体为主要原料,添加适量的分散剂、粘结剂及除泡剂制备浆料,采用流延法制备K0.5Na0.5NbO3膜片,研究了K0.5Na0.5NbO3固相含量、分散剂、粘结剂及除泡剂的种类及含量对流延浆料流延性能和对K0.5Na0.5NbO3陶瓷的影响。实验结果表明:流延膜的厚度在0.3mm时,选用三乙醇胺作分散剂效果最好,当固相含量在55wt%时,分散剂用量在2%时浆料的粘度为2000mPa.s,适合于流延工艺;粘结剂PVB的含量在8%时膜片强度较高。     

钙长石陶瓷基片的水基流延成型工艺研究

采用水基流延成型钙长石陶瓷基片坯体,研究分散剂、pH值、粘结剂及塑化剂对浆料流动性能的影响.实验结果表明:当浆料中固相含量为48vol%时,以聚丙烯酸胺为分散剂,浆料的pH值10,粘结剂含量为6.0wt%～8wt%时,增塑剂含量为4wt%～6wt%时,可以制备出稳定性良好、流动性适宜的钙长石流延浆料.通过SEM可以看出,高分子膜均匀包覆在钙长石颗粒表面,并且钙长石颗粒分布均匀,没有明显较大的孔隙.     

水基流延法制备（Sr，Ca）TiO3陶瓷基板的研究

以聚丙烯酸(PAA)为分散剂、聚乙烯醇(PVA)为粘结剂,聚乙二醇(PEG)为增塑荆,采用水基流延法制备了(Sr,Ca)TiO3陶瓷基板.研究表明:浆料pH值为10,分散剂PAA用量为0.8wt%,粘结剂PVA用量为7wt%,塑化剂与粘结剂的用量比值(R)为0.6时,可制备出固含量为56 wt%、分散稳定、具有适当粘度、流动性好的浆料.该浆料经流延,在55℃下干燥30min后,可以得到表面光滑、无裂纹、柔韧性好的流延膜坯,在1320℃下烧结,可以得到致密的(Sr,Ca)TiO3陶瓷基板.     

轧膜成型法制备燃料电池NiO/YSZ多孔阳极材料的研究

以水基轧膜工艺制备出了不同粘结剂含量的NiO/氧化钇稳定氧化锆(YSZ)固体氧化物燃料电池多孔阳极材料。研究了粘结剂含量和制备工艺条件等对多孔阳极微结构和性能的影响。实验结果表明:轧膜坯体的烧结温度对NiO/YSZ阳极烧结体的孔隙率有着决定的影响;为获得较高孔隙率和一定孔径分布的阳极烧结体,轧膜生坯的烧结温度应不超过1450℃。此外,粘结剂含量对轧膜生坯的烧结行为及烧结体的性能也有明显的影响,在相同的烧结温度下,高粘结剂含量阳极烧结体的孔隙率和孔径范围明显高于低粘结剂含量的烧结体,其中,粘接剂含量5%的生坯烧结后得到的NiO/YSZ阳极材料具有较好的综合性能;此外,NiO/YSZ材料还原后所得Ni/YSZ金属陶瓷多孔阳极的电导率随试样烧结温度的升高而升高,随测试温度升高而降低,800℃下的其电导率可达150S/cm。     

PVB对Ca-Ba-Mg-Al-B-Si-O玻璃/Al_2O_3材料性能的影响

以Ca-Ba-Mg-Al-B-Si-O玻璃和Al_2O_3为原料,加入流延剂后流延成型生瓷带,采用低温烧结法制备了玻璃/Al_2O_3系介电陶瓷材料。设计添加PVB粘结剂与KH-570型硅烷偶联剂协同优化流延工艺,重点研究了PVB粘结剂对浆料特性、生瓷带性能以及生坯烧结性能的影响。随着PVB相对分子量降低,浆料固含量增加,生瓷带体积密度增加,拉伸强度与断裂伸长率逐渐降低。PVB粘结剂中的PVB、PVA、PVAc基团在溶剂中溶解,产生一定粘度,使玻璃/Al_2O_3浆料具备合适流延的粘度。添加PVB-5s的玻璃/Al_2O_3浆料的固含量为67 wt%,相应生瓷带体积密度为1.92 g·cm~(-3),拉伸强度为1.42MPa,生瓷带表面光滑致密,生坯于850℃烧结良好,烧结体微观结构致密,介电性能优良,因此该体系材料比较适合用作低温共烧陶瓷材料。     

堇青石陶瓷基片水基流延成型工艺与性能研究

利用水基流延法,选用聚丙烯酸(PAA)为分散剂,聚乙烯醇(PVA)为粘结剂,聚乙二醇(PEG)为增塑剂,正丁醇为除泡剂,成功制备出了表面光滑、结构均匀、柔韧性良好的堇青石流延生带.当发现分散剂PAA含量为0.9%(wt)、粘结剂用量为7%～10%(wt),增塑剂的加入量为粘结剂用量的60%～90%,pH值为10左右时可以制备出稳定性良好、流动性适宜的堇青石流延浆料.然后对流延生带进行差热分析(DTA)和热重分析(TGA),在此基础上确定了流延生带的排胶温度为600℃,以及堇青石流延生带的烧结温度为1440℃,并在该温度保温70分钟的烧结条件下,获得了强度和致密度都较高的流延基片,其中烧结较好的流延基片的相对密度达96.14%.     

一种新型的水系流延工艺制备中温SOFC电解质YSZ薄膜

采用-种新型的水系流延工艺制备中温SOFC电解质YSZ薄膜浆料.研究了同时添加粘结剂和分散剂的浆料的流变性,不同含量粘结剂对这种浆料粘度的影响,该工艺对流延片的干燥特性、生坯密度和坯片烧结性能的影响.实验结果表明:该浆料的假塑性程度和浆料的粘度随着B-1070的含量增加而减小;发现采用该工艺的干燥时间明显缩短;YSZ坯片的生坯密度大大提高,相对密度达到55.3%.所得流延素坯在1450℃保温2小时烧结能获得相对密度达98.5%的YSZ电解质薄膜.     

水系流延氧化铝陶瓷基片的研究

采用水系流延成型法制备96氧化铝陶瓷基片.研究了四种不同类型的分散剂对96Al3O2浆料稳定性的影响.通过优化pH值和分散剂用量等因素,使浆料的稳定性达到最佳,获得固相含量高达83wt%的适合流延的96Al2O3水系浆料.以该浆料为原料,采用聚乙烯醇(PvA)、乳胶B-1070和PVA+B-1070复合粘接剂体系水系流延成型96Al2O3薄膜做比较.研究了不同粘结剂对流延工艺以及对流延坯片的影响.实验结果表明:不同种粘结剂加入后浆料的黏度和屈服值随PVA量的增加而增大,使得浆料的铺展性好;发现使用不同粘结剂对流延坯片的缩聚和干燥具有重要的影响.以复合粘结剂20wt%PVA+80wt%B-1070为粘结剂的流延素坯在1600℃保温2小时烧结能获得相对密度达97%以上(3.73g/cm3)的96Al2O3基片.     

5YSZ陶瓷基体的成型及烧结收缩率调节

为了提高5YSZ陶瓷基体的致密度和调节其烧结收缩率,通过流延法成型,优化了分散剂、消泡剂、球磨时间、固含量和胶含量。优化的条件为:分散剂含量0.9%,消泡剂含量0.63%,球磨时间22h+22h,固含量64%,胶含量29%。在优化的条件下,浆料分散均匀,生瓷带无气泡,5YSZ陶瓷基体烧结致密,且与Al2O3印刷层共烧良好。     

NiO/YSZ浆料凝胶固化、干燥、排胶及烧结工艺研究

采用凝胶注模工艺制备固体氧化物燃料电池(SOFC)阳极材料NiO/YSZ是目前的研究热点之一.本文主要研究了凝胶注模工艺中引发剂和催化剂的加入量对凝胶固化时间的影响,干燥温度对坯体失重的影响,固相含量、造孔剂的种类及用量对瓷体收缩率的影响,并对还原后瓷体的电性能进行了表征.采用SEM、EDS方法分析表征样品.实验结果表明:在实验选定的100 mL浆料中,浓度为5wt%引发剂的加入量为2.0 mL,浓度为0.5vol%催化剂的加入体积量为1.0 mL,凝胶时间可以控制在20 min以内.NiO/YSZ阳极材料最佳干燥温度是25 ℃,固相含量为45vol%、采用15wt%石墨作为造孔剂,在1350 ℃烧成的NiO/YSZ阳极与固体电解质YSZ收缩率相匹配,氢气还原后NiO/YSZ阳极在600～800 ℃电导率达到800 S/cm,符合SOFC阳极材料电导率的要求.     

Influence of ball milling contamination on properties of sintered AlN substrates

The AlN substrate was fabricated by the tape casting process, and its thermal conductivity and electrical conductivity were investigated for various ball milling times and types of milling media. The oxygen content was measured after ball milling, de-binding process, and sintering. The oxygen content after the de-binding process was 1.2–2.3 wt%, similar to that after milling. After the de-binding process, the specimens were sintered at 1850 ℃ for 3 h in nitrogen atmosphere. The thermal conductivity of the sintered specimens decreased from 158 W m⁻¹ K⁻¹ to 100 W m⁻¹K⁻¹ with increasing milling time. Simultaneously, the electrical conductivity decreased from approximately 10⁻⁷ Ω⁻¹ cm⁻¹ to 10⁻⁹ Ω⁻¹ cm⁻¹ at 500 °C when Al₂O₃ or ZrO₂ balls were used, whereas the electrical conductivity did not decrease when Si₃N₄ balls were used.     

Preparation of Na-beta″-alumina film by tape casting process

This study focused on the preparation of Na-beta″-alumina film by a tape casting process. The effects of solvent, dispersant, binder, plasticizer contents, as well as milling time on the rheological properties of the slurry were investigated. The dispersion of the ceramic powder in the slurry was optimized by ball milling an azeotropic mixture of methyethylketone (MEK) and ethanol (EtOH) as the solvent, 2 wt% triethanolamine as the dispersant, 7 wt% PVB as the binder for 4 h. Green Na-beta″-alumina thick films with thickness of 100–300 μm and homogeneous microstructure were obtained and further sintered at 1600 °C to obtain a relatively dense membrane with a thickness of ca. 100 μm. The conductivity of the sintered ceramic was comparable to that obtained by the conventional isostatic pressing and sintering method.     

Tape Casting of Lanthanum Chromite

The effects of process additives, ball milling, and solids loading were evaluated for tape casting suspensions of glycinenitrate-synthesized La_0.7Ca_0.31CrO₃ powder. An optimized formulation was obtained based on rheological characterization, electrokinetic sonic amplitude measurements, qualitative examination of green tapes, and the sintered microstructure. The tape casting formulation incorporated 66:34 methyl ethyl ketone/ethyl alcohol solvent, an aliphatic phosphate ester dispersant, and 80 wt% (35 vol%) solids. The best binder/plasticizer system was 12 wt% (15 vol%) poly(isobutyl methacrylate) and 5 wt% (6.3 vol%) benzyl butyl phthalate plasticizer (binder:plasticizer = 2.3). Cast tapes were sintered at 1300°C for 2 h, producing a bulk density of 96.2% theoretical, with linear shrinkage of 22% and an approximate grain size of 1.3 μm.     

蛭石基流延浆料的流变性能研究

以改性膨胀蛭石和滑石填料为原料,蓖麻油为分散剂,聚乙烯醇缩丁醛(PVB)为粘结剂,邻苯二甲酸二丁酯(DBP)为增塑剂,采用球磨法制备蛭石基流延浆料.考察浆料固含量和各组分添加量对浆料流变性能的影响,得出了合适的浆料配方为:固含量质量分数为50％、蓖麻油用量为粉体质量的2％、PVB用量为粉体质量的6％、DBP用量为R=0...     

Tape casting of zirconia for ion conducting membranes: A study of dispersants

Powders of fully yttria stabilized zirconium oxide have been studied in order to identify efficient dispersants for zirconia in tape casting slurries, and to verify that they do not impair the oxygen ion conductivity of the final membrane. Of eleven screened dispersants, only three were shown to be efficient. Sintered plates prepared with these dispersants had high and about equal oxygen ion conductivity (0.16–0.19 S cm⁻¹ at 1000°C). The use of a phosphate ester as dispersant, possibly leaving traces of phosphorus in the sintered plate, did not impair the oxygen ion conductivity. Fish oils, common dispersants for tape casting slurries, were not efficient for zirconia in the solvent system that was studied. The addition of binder and plasticizers to the dispersions to form tape casting slurries did not cause reagglomeration.     

TiN-Al2O3复合材料的导电性能

以微米TiN和α-Al2O3粉体为原料,采用无水乙醇为溶剂湿法球磨制备了TiN-Al2O3复合粉体,在氮气气氛中通过无压烧结得到TiN-Al2O3复合材料。研究了TiN含量对TiN-Al2O3复合材料导电性能的影响,实验结果表明:TiN-Al2O3复合材料的导电性能符合渗流理论,材料的电阻率取决于导电添加剂TiN的含量,TiN含量的增加能明显降低Al2O3复合材料的电阻率,在实验粒度配比下,其渗流阀值Vc为20.30%~22.13%。     

Aqueous tape casting processing of low dielectric constant cordierite-based glass-ceramics—selection of binder

In this paper, four different binders were investigated in the process of aqueous tape casting of cordierite-based glass-ceramics and their effects on the rheological behaviour of the suspensions and on the microstructures of the green tapes were compared. Meanwhile, a good compatibility between the dispersant and binder was found to be a predominant factor to obtain an optimised cordierite glass-ceramic tape. The microstructure of the green tape was observed by SEM and the weight loss during binder burn out process was determined by DTA/TG. The dielectric constant and dielectric loss of the sintered tapes (at 1150 °C for 2 h) was also measured.     

Fabrication of porous titania sheet via tape casting: Microstructure and water permeability study

In this article, we report the effects of slurry formulation and sintering conditions on the microstructure and permeability of porous titania sheets prepared by tape casting. It was found that solid concentration and binder content in the titania slurry play a vital role in the porosity and microstructure of the sintered titania sheets. Solid concentration and binder content were optimized based on the green tape quality and open porosity of the sintered titania sheets. The optimum solid concentration with the lowest surface roughness was obtained at 0.61 g/cm³. The effects of temperature and sintering time on the open porosity and crystal structure of the final product were also investigated. Increasing the sintering temperature from 1000 to 1100 °C resulted in increasing the pore size from 170 to 264 nm and decreasing the open porosity. Finally, water permeability of the porous titania sheets was studied to evaluate the permeation flux and maximum operating pressure. The results revealed that the permeability of the porous titania sheet is increased not only by increasing the open porosity but also by increasing the pore size.     

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.