水性粘合剂在电子陶瓷流延成型中的应用

总结了水性粘合剂的种类,分散形态,及其物理化学性质,如黏度、分子量、玻化温度等对电子陶瓷流延成型的影响,阐明了水性粘合剂对陶瓷浆料的稳定机理。从环保和MLCC高性能化的角度出发,指出采用水基流延的必然趋势,其重要研究方向在于提高水基流延的膜片强度。     

水基流延制备片式PTCR陶瓷的研究

采用sol-gel法制备纳米BaTiO3基PTCR粉体,并以其为原料,采用水基流延成型工艺制备片式PTCR。研究了在sol-gel法制备BaTiO3粉体中,施受主元素含量、陶瓷的烧成温度与PTC效应、晶粒尺寸的关系以及水基流延工艺中各种添加剂对浆料和膜片性能的影响。结果表明:以纳米BaTiO3粉体为原料、水基流延的片式PTCR坯片,在1240℃下就能半导化,所得陶瓷样品的升阻比高于104,温度系数大于13%℃–1,平均晶粒尺寸小于2μm。     

有机添加剂对氧化铝流延浆料流变性能的影响

系统研究了流延法制备氧化铝陶瓷基片过程中分散剂、增塑剂和粘结剂对浆料流变性能的影响。结果表明:采用分散剂GTO和S80制得的浆料黏度最低,TEP制备的浆料黏度最高。利用增塑剂PEG400和DBP都能获得较低的浆料黏度,随着增塑剂与粘结剂比值R的增加,浆料黏度显著降低。采用分散剂TEA、粘结剂PVB、增塑剂DBP制备的氧化铝浆料,当R值为0.8~1.6时,流延浆料黏度为1 071~1 671 mPa.s,流延生带质量较好。     

水性粘合剂对Ni-MLCC流延成型的影响

以聚丙烯酸酯乳液为粘合剂,采用水基流延成型制备了镍电极多层陶瓷电容器(Ni-MLCC)。利用扫描电子显微镜对膜片表面形貌进行了分析,研究了该水性粘合剂对Ni-MLCC陶瓷浆料黏度、膜片拉伸强度以及所制电容器的电性能的影响。结果表明:粘合剂的用量以质量分数10%为最佳,流延成型所得膜片表面光滑,无缺陷,瓷粉分散均匀,所制备电容器的各项电性能符合EIA-Y5V规范。     

CaAlSi系LTCC生带的流延制备及其烧结基板

以自制的CAS(CaO-Al2O3-SiO2)系玻璃作为功能相,通过分析不同的有机组分对流延浆料流变性能及分散稳定性的影响,优选:甲基乙基酮-乙醇为二元共沸溶剂;磷酸三丁酯为分散剂。浆料的黏度随粘结剂加入量增大而增大。随着增塑剂含量的增加,浆料黏度先减小后增大,当ζ(增塑剂:粘结剂)=0.6时,浆料黏度最低。流延浆料的最佳配方为:玻璃粉100.0g,粘结剂18.0g,磷酸三丁酯3.0g,增塑剂10.8g,溶剂为150.0～170.0g。流延生带样品于950℃烧结后获得相对密度达到96%,相对介电常数为6.97,介电损耗低于0.3%(1MHz)的玻璃陶瓷基板材料。     

可打印硼硅酸盐玻璃陶瓷浆料的制备及其流变性能研究

通过讨论粉末粒径、分散剂、固含量、粘结剂、增塑剂对陶瓷浆料流变性能及打印效果的影响规律,研究了高浓度、良好分散的可打印硼硅酸盐玻璃陶瓷浆料的制备方法,并采用3D打印直写技术实现了硼硅酸盐玻璃陶瓷基板的成型。研究结果表明:当分散剂为质量分数3%,粘结剂为质量分数4%,增塑剂与粘结剂质量比为0. 4,固含量为质量分数46%时,浆料可打印性较好,粘度约为2660 mPa·s。采用所制备浆料打印的基板表面平整,经过烧结后内部结构致密,相对介电常数为5. 4,介电损耗为0. 0017,满足电路基板的使用需求。     

铁氧体基片流延成型工艺的研究进展

介绍了铁氧体基片的研究现状及其流延成型工艺原理,重点分析了铁氧体粉体表面性质、浆料的稳定性以及不同流延体系的干燥机理,并对铁氧体基片流延成型的发展趋势进行了展望.     

ZnO压敏陶瓷的PVA系水基流延成型工艺及其性能

采用聚乙烯醇(PVA)系水基流延成型工艺制备了ZnO压敏陶瓷的水基流延膜。用粒度分析、粘度测量和动态机械热分析等方法研究了各组分对水基流延浆料性能的影响,用扫描电子显微镜和X射线衍射仪研究了水基流延膜的微观结构和物相组成。结果表明:在浆料质量比(陶瓷粉体:去离子水:分散剂:粘结剂:增塑剂:表面活性剂)=100:84.6:1:6:5.4:3时,所制水基流延膜无缺陷且微观结构均匀;另外,该流延膜经900℃烧结后具有良好的电性能:电压梯度E1mA=112.4 V/mm,非线性系数=34.6,漏电流密度JL=0.5×10–6A/cm2。     

水基流延法制备片式PTC陶瓷

以PVA和PAA乳液为粘合剂,用水基流延法制备了BaTiO3基片式PTC陶瓷基片。研究了粘合剂、固相含量等对浆料黏度及流变行为的影响,同时对流延基片的干燥工艺、烧成曲线等也进行了研究。结果表明,将流延干燥后的基片,在1 320℃空气中烧结30 min,所得PTC样品的升阻比大于6个数量级,温度系数大于16%/℃,能够满足叠层PTC器件的制备要求。     

无机添加剂对多层陶瓷电容器钯银内电极浆料的影响

为了满足多层陶瓷电容器陶瓷介质与钯银内电极浆料烧结一致性要求,研究了无机添加剂纳米BaTiO3和纳米ZrO2对钯银内电极浆料的烧结过程产生的影响。结果表明所用添加剂使MLCC烧结过程中钯银内电极浆料的收缩与陶瓷介质的收缩保持一致。     

Integrating Sub-Nano Catalysts into Metal-Organic Framework toward Pore-Confined Polysulfides Conversion in Lithium-Sulfur Batteries

Shuttle effect and sluggish redox kinetics of sulfur species still hinder the practical application of lithium-sulfur batteries (LSBs). Herein, a strategy of integrating sub-nano catalysts into metal-organic framework (MOF) is proposed for developing efficient sulfur host to tackle these issues. The designed MOF host (MOF-TOC) endowed with sub-nano Ti O clusters (TOCs) in the mesopores of MOF can act as an efficient reaction chamber in LSBs. Systematic electrochemical measurements and calculations demonstrate that MOF-TOC can trap and confine lithium polysulfides (LiPSs) via strong chemical interaction. Moreover, the highly active TOCs isolated in different nanopores can accelerate the bidirectional redox reaction of sulfur species through the d-p orbital hybridization with sulfur species. Benefiting from these merits, MOF-TOC delivers LSBs with remarkably improved areal capacity and cycling stability at high sulfur loadings and lean electrolytes. This work gives insight into the rational design of catalyst-containing MOF hosts and will shed light on the development of advanced catalytic hosts for high-performance LSBs.     

Effect of Polarization States on the Laser Performance of Passively $Q$-switched Yb:YAG/Cr,Ca:YAG Microchip Lasers

The polarization states of passively $Q$-switched microchip lasers were investigated by adopting different combinations of Yb:YAG, Cr,Ca:YAG crystals and ceramics. The results show that except for the random polarization oscillation of Yb:YAG/Cr,Ca:YAG all-ceramics combination, other three combinations including crystals exhibit linearly polarization. Highly efficient, nearly diffraction-limited beam quality, high peak power, sub-nanosecond passively $Q$-switched lasers were obtained for all combinations of Yb:YAG, Cr,Ca:YAG ceramics and crystals. The best laser performance was obtained with Yb:YAG/Cr,Ca:YAG crystals combination. The effect of polarization states on the laser performance was also addressed.      

Dielectric constant of barium titanate/cyanoethyl ester of polyvinyl alcohol composite in comparison with the existing theoretical models

A unique method has been introduced to measure the dielectric constant of polymer/ceramic composites using an effective medium instead of using the general methods of preparing bulk sintered pellets or films. In this work, a new and a simple method has been applied to measure the dielectric constant of polyvinyl cyanoethylate/barium titanate composites. The results are obtained by dispersing the ceramic powders in the polymer of a relatively low dielectric constant value. The dielectric constant of the composites is measured with varying ceramic volume percentages. The obtained results are compared with the many available theoretical models that are generally in practice to predict the dielectric constant of the composites. Then these results are extrapolated to comprehend the dielectric constant values of ceramic particles as these values form the base for the design of the composite. The precision and simplicity of the method can be exploited for predictions of the properties of nanostructure ferroelectric polymer/ceramic composites.     

双端端泵国产透明陶瓷Nd：YAG激光器研究

报道了激光二极管双端泵浦国产Nd:YAG透明陶瓷的实验研究.通过测量透过谱得出国产Nd:YAG透明陶瓷在1064nm处的损耗系数约为0.116cm-1.利用激光二极管双端泵浦国产Nd:YAG透明陶瓷,实现连续波最大输出功率为10.0W,相应的光-光效率为22.2%,这一结果是利用国产Nd:YAG陶瓷实现的最高功率激光输出.     

薄膜绝缘层对陶瓷厚膜电致发光显示器件的影响

采用丝网印刷技术，在Al2O3陶瓷板上印刷、高温烧结内电极及绝缘层制备出陶瓷厚膜基板，进而制备了新型厚膜电致发光显示器（TDEL），整个器件结构为陶瓷基板／内电极／厚膜绝缘层／发光层／薄膜绝缘层／ITO透明电极。对用不同薄膜绝缘材料制备的显示器件的特性进行测试、比较、分析，结果表明薄膜绝缘介质层对器件的阈值电压、发光亮度均有一定的影响，以复合绝缘层的性能最优。最后对器件的衰减特性进行了初步分析。     

磁电复合薄膜用高性能压电陶瓷靶材的制备

采用固相法制备了高性能的Pb(Zr0.54Ti0.46)O3压电陶瓷靶材。通过调整Sr掺杂比例,获得高性能的压电陶瓷配方,以高性能锆钛酸铅(PZT)粉体为原料,经冷等静压和高温烧结制备出磁控溅射需要的、直径为73.6mm的压电陶瓷靶材。     

PZT压电纤维的制备及性能研究

以溶胶-凝胶(Sol-Gel)工艺制备的PZT陶瓷粉为原料,采用氧化物粉末装管法制备PZT压电陶瓷纤维.SEM分析显示,该陶瓷纤维呈圆柱型形貌,直径约为250 μm.分析了不同烧结温度下PZT陶瓷纤维的断面微结构及Pb含量变化,得出PZT陶瓷纤维的最佳烧结温度为1 000 ℃.XRD分析表明,此温度下烧结的陶瓷纤维呈单一的钙钛矿结构.实验结果表明,采用氧化物粉末装管法制备的陶瓷纤维大小均匀,结构致密,具有高长径比,克服了传统工艺不能制备结构致密的长纤维的缺陷.     

一种应用于12 GHz的AlN多层陶瓷外壳

以AlN材料为陶瓷基材,采用陶瓷绝缘子的射频传输端口结构及陶瓷焊球阵列封装形式,结合多层陶瓷加工工艺,设计并制备了一款可封装多个芯片的X波段AlN陶瓷外壳。采用应力仿真软件对外壳进行结构设计,利用电磁仿真软件对该外壳的射频端口进行仿真优化。采用微带线直接穿墙形式,设计了共面波导-带状线-共面波导的射频传输结构,并与陶瓷外壳进行一体化设计和制作。利用GSG探针对外壳样品进行测试,实测结果表明,在0~12 GHz频段内,外壳射频端口的插入损耗不小于-0.5 dB,回波损耗不大于-15 dB,AlN一体化外壳尺寸为10.25 mm×16.25 mm×4 mm,可广泛应用于高频高速信号一体化封装领域。     

Controllable Ceramic Green‐Body Configuration for Complex Ceramic Architectures with Fine Features

Fabrication of dense ceramic articles with intricate fine features and geometrically complex morphology by using a relatively simple and the cost‐effective process still remains a challenge. Ceramics, either in its green‐ or sintered‐form, are known for being hard yet brittle which limits further shape reconfiguration. In this work, a combinatorial process of ceramic robocasting and photopolymerization is demonstrated to produce either flexible and/or stretchable ceramic green‐body (Flex‐Body or Stretch‐Body) that can undergo a postprinting reconfiguration process. Secondary shaping may proceed through: i) self‐assembly‐assisted shaping and ii) mold‐assisted shaping process, which allows a well‐controlled ceramic structure morphology. With a proposed well‐controlled thermal heating process, the ceramic Sintered‐Body can achieve >99.0% theoretical density with good mechanical rigidity. Complex and dense ceramic articles with fine features down to 65 μm can be fabricated. When combined with a multi‐nozzle deposition process, i) self‐shaping ceramic structures can be realized through anisotropic shrinkage induced by suspensions' composition variation and ii) technical and functional multiceramic structures can be fabricated. The simplicity of the proposed technique and its inexpensive processing cost make it an attractive approach for fabricating geometrically complex ceramic articles with unique macrostructures, which complements the existing state of‐the‐art ceramic additive manufacturing techniques.     

Reduced Temperature Coefficient of Capacitance (TCC) of Embedded Capacitor Films (ECFs) for Organic Substrates using SrTiO3 and Multifunctional Epoxy

Epoxy/ceramic composites have attracted great interest as embedded capacitor materials, mainly due to the process compatibility of epoxy with printed circuit boards (PCBs). However, one of the potential problems of epoxy/ceramic composites is the temperature dependence of their dielectric properties. This study focuses mainly on reducing the temperature coefficient of capacitance (TCC) of epoxy/ceramic composites using multifunctional epoxy and SrTiO₃ powder. The TCC of an epoxy/ceramic composite mainly depends on the properties of its epoxy and ceramic powder. Using multifunctional epoxy, the epoxy resin showed two glass-transition temperatures, resulting in a lower dimensional change after the first glass-transition temperature. Additionally, the TCC of epoxy/SrTiO₃ ECFs can be decreased by increasing the SrTiO₃ powder content. As a result, reduced TCC of epoxy/ceramic composite capacitors using a multifunctional epoxy and SrTiO₃ powder was successfully demonstrated for embedded capacitors in organic substrates.