Electrodeposition Method for Terminals of Multilayer Ceramic Capacitors

A method using a combination of electroless and electrolytic plating was developed to provide an alternative method for forming the end terminals of multilayer ceramic capacitors. Electrodeposited terminals were formed by using electroless copper followed by electrolytic nickel plating. The electrical characteristics of the electrodeposited terminal capacitors were compared with standard capacitors and found to be identical.     

Derivatization of Preformed Polymers to Produce Ceramic Precursors

The feasibility of producing derivatized preformed polymers to be used as ceramic precursors was explored. A borane derivative of polyethyleneimine (PEI) was prepared through a transamination reaction involving Me₃NBH₃. Higher boron loadings were possible with Me₃NB₃H₇. The borane derivative could be cast into films and produced boron nitride upon pyrolysis. Similarly, polyethyleneimine hydrochloride was converted into the cyanohydroborate derivative through a reaction with NaBH₃CN. This derivative was also accessible through a transamination reaction. Both materials produced boron nitride upon pyrolysis. Polyallylamine hydrochloride could not be derivatized. Silyl derivatives of PEI were also prepared, but the products obtained afforded low ceramic yields upon pyrolysis.     

Organogels: An Alternative Edible Oil-Structuring Method

Structuring liquid oils has become an active area of research in the past decade, mainly due to pressures to reduce saturated fat intake and eliminate trans fats from our diets. However, replacing hard fats with liquid oil can lead to major changes in the quality of food products. Recent strategies to impart solid-fat functionality to liquid oils include the addition of unusual compounds to oil, leading to its gelation. These include small-molecule organogelators such as phytosterols and 12-hydroxystearic acid, which self-assemble into crystalline fibers which trap oil. Other crystalline additives include waxes, ceramides, monoacylglycerides, and other surfactants. Recently, the polymer ethyl cellulose was reported to form a polymer gel in triacylglyceride (TAG) oils. Other non-conventional strategies also include the formation of protein-stabilized cellular solids with oil trapped within the cells. In this review, we summarize the research on each one of these components in order to provide a comprehensive overview of the state of the area in oleogel research and provide future perspectives.     

Microwave Bandgap in Multilayer Ceramic Structures

A multilayer ceramic structure with a photonic bandgap (MC-PBG) was fabricated by a method of tape casting combined with screen printing. The MC-PBG structure is a two-dimensional array with either rectangular or hexagonal metal coils in a ceramic matrix. The metal coils are connected to the base metal layer in the ceramic substrate to form a monolithic body. The surface-wave dispersion properties of these MC-PBG structures were measured. A stop band, which is significantly influenced by the symmetrical characteristics of the inductor–capacitor ( LC ) arrays, was found in both the structures in the frequency range of 2.0–3.5 GHz. Because of their effective surface-wave suppression, MC-PBG structures can be used as high-performance antenna substrates to enhance the broadside gain of patch antenna devices.     

New Alumina‐Based Novel Ceramic Nanopigments: An Alternative to the Purple of Cassius

The present article presents first comparative study on three different dry solgel methods of producing new alumina‐based dark violet, light pink ceramic nanopigments as well as ruby‐red ceramic nanopigment — an alternative to the Purple of Cassius. Gold nanoparticles are built directly on a carrier of an aluminum oxide nanopowder, which finally yields Al₂O₃/Au nanopowders possessing colors ranging from light pink to light violet as well as ruby‐red.     

Influence of Electroless Nickel Plating on Multilayer Ceramic Capacitors and the Implications for Reliability in Multilayer Ceramic Capacitors

The influence of electroless nickel plating on lead-based relaxor ferroelectric multilayer ceramic capacitors (MLCs) was studied by a comparison experiment. It was found that the influence is related to reactions in the electroless plating. It is proposed that adsorbed hydrogen atoms generated in electroless plating can diffuse into the ceramic bodies of MLCs and undergo some reduction reaction with them, resulting in the failure of electroless nickel plating. The implications for the negative influence of electroplating on MLCs and for the degradation in MLCs are also included, in which much attention is paid to the reduction reaction of hydrogen atoms generated by electrolysis of water.     

利用含钴工业废料研制黑色陶瓷颜料

本从Cr-Fe-Mn-Cu-Co系统进行研究，对含钻工业废料添加Cr2O3、CuO等物质进行试验。通过配方优化、调整，最终获得符合工业生产的黑色颜料，随后对坯釉适应性又做了补充试验。     

Slurry Chemistry Control to Produce Easily Redispersible Ceramic Powder Compacts

The slurry-based Three Dimensional Printing (3DP^TM) process requires the production of an easily redispersible powder bed from a well-dispersed slurry. Understanding and control of the interparticle potential in the dispersed state, as well as in the dry consolidated state, are important. The strength of the particle–particle interactions in the dry state determines the redispersion efficiency. One factor that controls the interparticle strength is the chemical stability of the ceramic powders in the dispersed state. For unstable powders, a partial dissolution and/or hydration of the powders can occur and eventually impede the redispersion by forming insoluble salt bridges at the necks of the particles. Redispersion of the powder bed can be improved substantially by weakening the strength of the particle–particle bonds. The formation of strong chemical bonds between particles should be avoided by adjusting the slurry pH to an appropriate range where the powders are chemically stable in the slurry. Replacement of the chemical bonds by soluble physical bonds, using a low-molecular-weight hydrophilic polymer, also reduces the interparticle strength and enhances redispersion.     

Electrode-Based Causes of Delaminations in Multilayer Ceramic Capacitors

Delaminations are a principal quality problem in the manufacture of multilayer ceramic capacitors (MLC's). They are defined as a separation of the electrode and dielectric layers and can result in electrical shorts and/or life failures. Delaminations originate from many sources in MLC manufacture, but we have identified four which are caused by the electrode. High levels of organic resin in the electrode paste lead to high resin content in dried electrode prints, requiring removal of large amounts of organic residues during burnout, causing delaminations. Catalysis of these organics by the precious metals also causes delaminations from rapid evolution of gas and heat release during burnout. Poor adhesion of the dielectric tape layers to dried electrode prints during MLC buildup can cause "green-state" delaminations which remain through firing. Sintering shrinkage mismatch between the electrode and dielectric layers leads to internal stresses in MLC's, resulting in delaminations. We discuss these electrode-based mechanisms of delamination and the design of electrode pastes which solve these problems.     

多层压电陶瓷变压器等效电路模型及其特性研究

提出了一种新颖的多层压电陶瓷变压器等效电路模型和分析方法。基于多层压电变压器陶瓷片在结构上的电学并联关系，建立了其在电路上的并联表示模型，并把输出电量与输入电量之间的关系用矩阵形式表达，简化了分析过程，为压电变压器的设计提供了一种通用而简单的分析方法。仿真结果验证了该方法的有效性，获得了良好的输入阻抗特性和升压比特性，升压比约为1200。     

虾青素制备新方法研究

用南极红酵母（Rhodotorula sp）NJ-0211发酵生产虾青素。考察了摇床的转速、培养时间和培养温度对南极红酵母培养的影响,确定了NJ-0211的最佳培养条件为转速100r／min,时间10d,温度4℃。在此培养条件下,虾青素的含量为873．75μg／g干菌体,比文献报道的高2．5倍。     

陶瓷色料的调配方法

本针对陶瓷色料的特殊性，以及基础釉对色料发色的影响，依据颜料学的三原色定理和色料发色的基本光学原理，结合实际工作中出现的情况和经验，讨论如何进行陶瓷色料颜色的调配和需要注意的一些问题，并就如何进行有效、快捷的调配陶瓷色料颜色提出一些见解。     

等温热压印法制备超疏水薄膜

以刷涂有疏水性SiO2微球的筛网作为模具,通过等温热压印的方法,在聚乙烯（PE）塑铝复合薄膜上制备出超疏水表面。对压印压力、筛网目数、SiO2微球直径等参数对制品表面微结构形貌和疏水性能的影响进行了研究。结果表明,该方法可以在PE塑铝复合薄膜表面构筑出具有良好疏水效果的二级复合微结构;在压力作用下,SiO2微球会与PE基体共混形成复合体系,使得SiO2微球与基体的连接更加稳定;增加热压印压力可以增大微米级结构的深度,但是过大的压力会导致SiO2微球被PE覆盖,合理的压印压力应在8~12 MPa之间;减小SiO2微球的粒径可以进一步提高接触角数值;制品对水的接触角达到150°,滚动角低至1°,达到了超疏水的标准。     

以铝镁尖晶石为原料利用选择性脱碱法制造多孔陶瓷

以镁、铝和硅的化合物一起结晶的方法合成MgO—Al2O3-SiO2系超细粉料,并利用该粉料制成了二相型尖晶石-堇青石复合材料。研究了化学不稳定相在苛性钾和氢氟酸溶液中选择性脱碱的过程。测定了二相型材料加工的最佳条件,以利于以铝镁尖晶石为原料制造开口气孔率大于50％的陶瓷。     

Control of Stress Concentration in Surface‐Mounted Multilayer Ceramic Capacitor Subjected to Bending

Failure of surface‐mounted multilayer ceramic capacitor (MLCC) results mainly from bending of the printed circuit board during handling and applications. Cracking of MLCC normally initiates at the junction of the bottom end of termination and the dielectric ceramics and it would cut through dielectric ceramics and electrodes to result in the capacitance loss and failure of MLCC. The purpose of this study was to mitigate the stress concentration and to shift the stress concentration location toward the side end of MLCC to minimize the number of electrodes cut by cracking. To achieve this, effects of the stiffness and the thickness of the solder and the size of MLCC on the location of crack initiation and the fracture load were examined. Nanoindentation was performed to obtain the mechanical properties of the constituents of the system. Finite element analyses were conducted to simulate the stress field in the surface‐mounted MLCC subjected to bending and the results were compared to the observed crack initiation locations and the fracture load. The outcome would provide guidelines in mounting and designing of MLCCs to enhance its reliability and lifetime.     

An Indentation Method for Measuring Matrix-Fiber Frictional Stresses in Ceramic Composites

A simple method for measuring frictional stresses between the mairix and individual fibers in a ceramic composite is described. A standard microhardness indenter is used to apply a force to the end of the fiber and depress it below the matrix surface. The frictional stress is calculated from measurement of the applied force and the amount of slipping between the fiber and matrix.     

热压注产品生产工艺特点

介绍了热压注产品生产中的技术关键及克服缺陷的方法。     

一种多元高浓度复合液肥的生产方法

介绍了一种新型多元高浓度复合液肥的研制方法及其大面积田间应用的情况     

陶瓷高温气体过滤器在合成氨净化压缩中的应用

针对合成氨工艺常用的除原料气中油、水、粉尘的方法,对在实际运行中容易出现的问题,提出了用陶瓷高温气体过滤器除去原料气中的粉尘,并介绍了其应用情况.