多层异质复合结构激光钎焊工艺

压电陶瓷变压器（PECT）是一种新型的电子元器件材料，具有多层异质复合结构。目前多采用手工烙铁对其侧电极进行连接，主要缺点是：工作效率和成品率低，难以保证各陶瓷片之间的全连通和控制金属间化合物的形成，焊接质量较差，返工率高等。针对压电陶瓷变压器侧电极的连接问题，本文提出了激光钎焊的焊接方法，采用金属丝网辅助钎膏钎焊工艺，对PECT发电元件的侧电极进行激光钎焊。试验结果表明，该工艺解决了多层异质复合材料元件不同性质分割区域表面的连接问题，全连通率高，热影响小，激光钎焊接头抗拉强度与疲劳强度均较高。     

银粉对PZT压电陶瓷电极表面结构和性能的影响

本文重点讨论不同银粉对PZT（PbZrO3-PbTiO3)压电陶瓷电极表面结构及性能的影响。选择合适的银粉，配制成银浆，可以烧结出结构平整，致密，性能优良的PZT表面银电极。     

气中连续放电辅助加工中的控制系统设计

以压电陶瓷微位移驱动原理为基础，对精密驱动技术在气中连续放电辅助加工控制系统中的应用进行了研究。设计了一个包括单片机、压电陶瓷驱动电源、信号检测及处理电路组成的气中连续放电辅助加工控制系统。该系统能根据加工时两电极间电压的变化自动寻找最佳放电间隙，并维持辅助加工中的连续放电,可应用于一些高硬度、难切削材料的辅助加工领域。     

无铅压电陶瓷及其应用研究

随着社会可持续发展战略的实施和人们环境意识的加强，无铅压电陶瓷及其应用已成为了当前铁电压电材料及其应用研究的热点。本文根据近期国内外有关无铅压电陶瓷的发展，结合本课题组肖定全教授等近年在无铅压电陶瓷的研究，对无铅压电陶瓷的研究进展及应用现状进行了综述，重点介绍了BaTiO3基、Bi1／2Na1／2TiO3基、碱金属铌酸盐基、钨青铜结构和铋层状结构五大体系无铅压电陶瓷的性能、本课题组主要发明的无铅压电陶瓷体系以及BNT基无铅压电陶瓷在滤波器上的应用和发展前景。     

电子打火机电极的成形工艺及模具

电子打火机电极的成形工艺及模具广东佛山市温控器厂马庆麟１引言压电陶瓷电子打火机装置广泛用于燃气热水器、燃气炉具、电子打火机等产品上。用量大，国内市场年需要量超过五千万只。目前一些单位依靠进口，其价格比国内产的高几倍。电子打火机装置关键的两个零件，电极...     

超声行波马达环形定子的振动模式

利用傅立叶变换对由环形压电陶瓷片激励的超声行波马达环形定子的振动模式作了分析,说明了在保持为某一振动模式设计的压电陶瓷片塗银电极图形不变的情形下,改变激励电源的频率到某些值时,也能激发起其它一些的振动模式.并实验验证了部分结果.     

多层压电陶瓷变压器的振动与疲劳

低温共烧多层压电陶瓷变压器具有体积小、转换效率高、升压比高、无电磁辐射等优点,是传统电磁变压器在小功率仪器设备上理想的替代品.采用Pb(Mg_(1/3)Nb_(2/3))O_3-Pb(Ni_(1/3)Nb_(2/3))O_3-Pb(ZrTi)O_3低烧瓷料,通过干法流延多层叠印技术制备出高性能多层压电陶瓷变压器样品,内电极银钯浆配比7:3.利用Polytec300-F扫描激光测振仪测试了多层压电陶瓷变压器沿长度伸缩振动的位移和模态.通过对压电变压器振动性能和升压比的测试,研究了器件性能衰减及疲劳特性.     

BS含量对xBS-(96-x)PZT-4LN压电陶瓷组织与性能影响

用前驱体法制备了xBS-(96-x)PZT-4LN(x=22,26,30,34)压电陶瓷,研究了BS含量对陶瓷微观形貌、物相组成、介电和压电性能的影响。结果表明,BS含量对x BS-(96-x)PZT-4LN压电陶瓷的晶粒尺寸影响不明显;体系处于三方相到四方相之间的过渡范围;随着BS含量增加,压电和介电性能先增大后下降,当x=26时,陶瓷介电常数εr、压电常数d33、平面机电耦合系数k_p、介电损耗角正切tanδ和机械品质因数Qm均获得极值。     

基于压电陶瓷的微粒控制技术研究进展

对压电陶瓷激发超声波对微粒控制技术的工作原理进行探讨。在生物医药方面，对流体的控制是关键技术，已有的结构多较为复杂且不易加工。为了使流体控制结构简单且容易集成和产业化，对压电陶瓷激发行波实现流体输运的技术进行了研究，并且对压电陶瓷激发行波的原理和驱动流体运动的机理进行了探讨。     

Ag^＋掺杂Na0．5K0．5NbO3无铅压电陶瓷的无压烧结及性能研究

铅基压电陶瓷在制备、使用及废弃处理过程中都会造成环境污染，随着环保意识的增强，无铅压电陶瓷必将逐步替代铅基压电陶瓷。Na0．5K0．5NbO3是一种很有潜力的无铅压电陶瓷，掺杂各种元素提升Na0．5K0．5NbO3陶瓷的压电性能成为当今研究热点之一。本研究以Ag2O、Na2CO3、K2CO3、Nb2O5为原料，经750℃焙烧分别合成了Na0．5K0.5NbO3和AgNbO3粉料，再经配料、混料与成型，在1060℃埋粉烧结，制备出Ag^＋掺杂的Na0.5K0．5NbO3无铅压电陶瓷（xAgNbO3-（1-x）Na0.5K0．5NbO3，ANKN），并在较宽成分范围内（Ag^＋含量，x=0-50at％）系统研究了Ag^＋掺杂对ANKN陶瓷性能的影响。XRD结果表明，ANKN陶瓷的主相为钙钛矿型结构，当x〉16at％，开始出现K5-75Nb10．85O30杂相，随着Ag掺杂量的增加，杂相的衍射峰增强。电学性能测试结果表明，当x〈20at％，随Ag掺杂量的增加ANKN陶瓷的压电常数、介电常数等略有升高；当x〉20at％，ANKN陶瓷的各项性能均开始降低；Ag掺加量为x=16at％时ANKN陶瓷性能最佳，压电常数d33达到110pC／N，平面机电耦合系数kp为30％，相对介电常数εr为358，居里温度Tc为300℃。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.