紫铜/Al_2O_3陶瓷/不锈钢复合结构钎焊接头残余应力研究

采用有限元数值模拟的方法研究AgCuTi钎焊紫铜/Al_2O_3陶瓷/不锈钢复合结构的形变和残余应力分布情况,并对模拟结果进行实验验证。结果表明:残余应力主要分布在接头区,并且该区形变较小。陶瓷端的残余应力对接头性能影响较大,由于线膨胀系数差异过大,不锈钢陶瓷侧易产生裂纹缺陷,接头倾向于在该区域断裂,紫铜侧陶瓷端TiO反应层的形成导致该区域裂纹的出现,降低了接头的性能。研究各应力分量对最终残余应力的贡献,结果显示环向应力和轴向应力在陶瓷端所产生的拉应力是造成接头强度降低的主要因素。接头拉剪实验表明,接头主要在靠近不锈钢侧的陶瓷端断裂,验证了模拟结果的准确性。     

A new method for preparation of direct bonding copper substrate on Al2O3

The oxygen content is usually difficult to control in direct bonding copper process. In this study a new method for preparation of direct bonding copper on alumina ceramic substrates was realized. 96% Al₂O₃ ceramic substrates were first oxidized by pasting a thin layer of Cu₂O and firing at 1150 °C in air. Then copper foil was bonded to the substrate by heating to 1070 °C in pure N₂ atmosphere. Microstructure and composition of the interface between the copper and Al₂O₃ ceramic were analyzed. The XRD and EDS results show that an interphase of CuAlO₂ was formed and a eutectic transformation between oxygen and copper took place at the interface of the copper and the ceramic substrate. The interface was much thicker than the traditionally bonded substrates, which resulted in a better bonding strength. The directly bonded copper alumina substrate samples showed no evidence of de-bonding after 50 thermal cycles comprising quenching from 220 °C to room temperature.     

Interface reactions in the system sialon-Cu-Cu2O

The interface reactions between an /gb-sialon ceramic and Cu, Cu₂O or a Cu-Cu₂O mixture have been studied. A fully dense sialon ceramic material prepared by pressureless sintering at 1775 ° C with 6 wt% Y₂O₃ as sintering aid, were coldpressed together with Cu, Cu₂O or Cu-Cu₂O mixtures into cylindrical tablets. These samples were heat treated at 700, 850 and 1000 ° C in evacuated silica tubes. The reaction zones formed between the sialon and the powder compacts were studied in a SEM equipped with an EDS system. No reaction between copper and sialon ceramic could be detected in spite of prolonged heat treatment at 1000 ° C. Cu₂O reacted with the ceramic at 850 and 1000 ° C to form a glass containing copper and all the other sialon components. The interaction between the sialon material and the Cu-Cu₂O powder compacts was characterized by a redox reaction. The sialon was thus oxidized to SiO₂ and N₂ while Cu₂O was reduced to copper. A glass phase containing silicon, aluminium, yttrium and copper was also formed in the reaction.     

自蔓延高温合成陶瓷内衬复合铜管的研究

将自蔓延高温合成技术与离心铸造技术结合，开发了陶瓷内衬复合铜管技术，可在铜管内表面涂敷耐磨性和耐蚀性优良的陶瓷涂层。为提高陶瓷涂层致密度、韧性和结合强度，研究了添加剂的影响。结果表明，在铝热剂中加入SiO2和CrO3可提高致密度，加入Na2B4O7可提高结合强度，加入ZrO2可提高断裂韧性。陶瓷内衬复合铜管应用于管坯结晶器，可提高其使用寿命，降低成本。     

陶瓷散热片用铜浆玻璃相的制备

厚膜陶瓷散热片的制备工艺一般为丝网印刷铜浆、烧结、化学镀镍3部分。目前印刷在散热片上的铜浆,经化学镀镍工艺后附着力下降,因此研究制备导电性好、导热性优和附着力高的铜浆是制备陶瓷散热片的关键。通过对铜浆玻璃相的制备、玻璃软化温度的测定和玻璃釉在化学镀镍液中的耐蚀性测试,得到了耐蚀性较好的玻璃釉,其玻璃相成分为40%SiO₂-31%Bi₂O₃-5%B₂O₃-3%Al₂O₃-5%TiO₂-3%CaO-4%SrO-5%Na₂O-5%K₂O（质量分数,下同）。     

氧化铝陶瓷局部活化及选择性化学镀铜的研究

为解决陶瓷表面局部化学镀存在的问题,研制了一种针对氧化铝陶瓷局部化学镀铜前处理用的活化胶,其由具有活化能力的银盐(或钯盐)和粘稠的复合物有机载体组成.将活化胶印于氧化铝陶瓷表面,经500℃高温烧结形成局部活化层后,可直接置于化学镀液中进行镀铜处理,得到与印刷图形一致的局部镀铜层.利用电化学工作站测定样品在化学镀铜溶液中电位随时间的变化情况,考察不同活化条件对Cu2+还原的催化活性,利用SEM/EDS进行表面形貌及成分分析,确定了活化胶中银盐和钯盐的适宜浓度.结果表明,该两种活化胶应用于氧化铝陶瓷表面化学镀铜的活化工艺,可实现敏化活化的一步化,使陶瓷表面局部化学镀工艺流程简化,成本降低,具有较高的实用价值.     

Co-continuous metal-ceramic nanocomposites

A room temperature technique was developed to produce continuous metal nanowires embedded in random nanoporous ceramic skeletons. The synthesis involves preparation of uniform, nanoporous ceramic pre-forms and subsequent electrochemical metal infiltration at room temperature, so to avoid material incompatibilities frequently encountered in traditional high-temperature liquid metal infiltration. Structure and preliminary evaluations of mechanical and electronic properties of copper/alumina nanocomposites are reported.     

Electronic behaviour of iron ions at copper sites

The electronic properties of the ceramic superconductor Y-Ba-Cu-Fe-O system with different amounts of iron cations versus temperature are discussed. The spin fluctuations of copper and its relation to the superconducting state are discussed from the point of view of the mixed valence state of copper ions. The results suggested a spin-glass behaviour at low temperature.     

The interaction of molten copper with solid iron

The interaction phenomenon of solid iron with molten copper was studied by investigating the interfacial microstructures of Cu/Fe and Cu-Ag/Fe and the migration mechanism of molten copper and Cu-Ag alloy into the solid iron. A small quantity of copper or Cu-Ag alloy was melted in a solid iron cylindrical specimen at temperatures ranging from 1100 to 1400° C using a high-frequency induction furnace. The Cu/Fe interfacial microstructure consisted of iron dendrites in the copper matrix, and an iron dendrite layer and a copper-penetrated solid solution zone adjacent to each other at the interface. Irrigation effects and grain-boundary penetration were observed partially at lower temperature. The addition of silver to molten copper causes inactivation of the reaction, resulting in the formation of thin reaction layers at the interface. The migration of molten copper and Cu-Ag alloy into solid iron occurs mainly with the formation of an iron-saturated layer due to iron dissolution and a copper-penetrated solid solution zone due to incipient volume diffusion. The copper penetration appears to be dominated by volume diffusion at high temperatures and by both volume and grain-boundary diffusion at low temperatures. Increased silver content in the molten copper decreases the penetration rate constant.     

TC4合金陶瓷模粉末冶金工艺研究

目的 研究陶瓷模粉末冶金工艺,通过数据积累指导未来工程化应用。方法 通过氧化钇陶瓷模壳技术,研究构件与铸件的化学成分、力学性能及微观组织。结果 粉末件在包套高度方向上金属收缩率明显大于包套水平方向的收缩率;粉末构件内部质量良好,无夹杂,其致密度达到了99.5%;粉末构件室温力学性能优于同成分铸件,部分室温力学性能达到TC4锻件水平。结论 采用稀土氧化钇面层、硅溶胶铝矾土背层涂料工艺得到的陶瓷型可用于陶瓷型壳粉末冶金工艺;构件尺寸收缩率在每个方向上不是均匀的,和其在包套内放置方向、包套放置方向都有关系;构件晶粒细小均匀,组织为由细小的魏氏体板条α相与相间β相、等轴α相所组成,等轴α相分布不均匀,主要分布在晶界上;其构件室温力学性能优于同成分铸件力学性能,部分性能达到了锻件水平。     

SiCW对TiB2／25SiCW陶瓷材料高温增韧效果的影响

采用热压工艺制备了ＴｉＢ２／ＳｉＣＷ陶瓷复合材料，结果表明：在ＴｉＢ２基体中添加体积分率为２５％的ＳｉＣ晶须，可显著的提高材料的断裂韧性和抗弯强度，实验表明，ＴｉＢ２／２５ＳｉＣＷ陶瓷材料的断理解韧在１０００℃内随温度的升高而增大，其原因是由于的升高使晶须径向残余压应力松驰，晶须拔出所需要的力ＦＰ减小，温度越高，晶须拔出越容易，能够被拔出的晶须量增多，拔出功增大，在低落曙下晶须以脆性断裂为主，在高     

Flip-Chip Packaging for a Two-Dimensional Thermal Flow Sensor Using a Copper Pillar Bump Technology

A flip-chip packaged two-dimensional (2-D) thermal flow sensor fabricated in CMOS technology is presented. The sensor consists of polysilicon resistor heaters, Al/polysilicon thermopiles, and a substrate bipolar transistor located in the center of the sensor chip. The thermopiles and the transistor were used to measure the change of the flow-induced temperature distribution on the flow-sensing surface. The sensor chip was flip-chip packaged on a thin ceramic substrate using a copper pillar bump technology. The polysilicon resistor provides the necessary overheat of the chips, and thermal interactions with the flow are achieved via the pillar bump and the thin ceramic substrate. The operating principle for the packaged sensor remains the same as before packaging. The backside of the ceramic substrate provides a smooth surface for the sensor to be exposed to the flow. Meanwhile, the ceramic substrate holds the sensor chip and protects it from being contaminated or even destroyed by the corrosive environment. The packaged flow sensor shows the good performances compared with the unpackaged sensors. It can detect airflow speed up to 30 m/s with accuracy of 0.5 m/s and airflow direction in a full range of 360 with an accuracy of 6 at room temperature.     

AlN陶瓷的薄膜金属化及其与金属的焊接研究

针对AlN陶瓷在微波管中的应用特点 ,采用磁控溅射镀膜方法对AlN陶瓷进行表面金属化 ,并与无氧铜焊接 ,测试焊接体的抗拉强度并对陶瓷 金属接合界面进行了微观分析。     

The effects of plastic deformation on stress wave propagation in multi-layer materials

The behavior of a multi-layer material at high strain rate and the effect of plastic deformation on stress wave propagation were investigated by a combination of experimental and numerical techniques. Plastic deformation effects were studied in multi-layer materials consisting of ceramic, copper and aluminum subjected to large strains under high strain rate loading. First, stress wave propagation behavior for the monolithic metals was studied, and then extended to multilayer combinations of these metals with each other and with a ceramic layer. The axial stress distributions were found to be non-uniform in the elastic deformation range of the specimen. The degree of non-uniformity was much more pronounced in the multi-layer samples consisting of different materials. The presence of a ceramic layer increased the magnitudes of stress gradients at the interfaces. It was also found that a major effect of plastic deformation is a tendency to produce a more homogeneous stress distribution within the components. The implications of these observations for practical systems are discussed.     

Electron diffraction of precipitates at copper-cordierite interfaces

The precipitation of copper particles at the interface between a copper rod and a MgO-Al₂O₃-SiO₂ ceramic was investigated by Robinson back-scattered SEM and convergent beam micro-diffraction TEM. A 20 μm wide zone depleted of copper separated the copper rod from a 70 μ m region of copper-containing particles dispersed in the ceramic matrix. The precipitates were crystallographically identified as elemental copper by matching of convergent beam, inelastically-scattered, Kikuchi patterns.     

Ti基非晶合金及其SiC陶瓷骨架复合材料动态压缩力学行为研究

为了验证Ti基非晶合金和陶瓷两种材料三维连通网状结构的复合优势,制备出具有优良抗冲击性能的复合材料,本文采用铜模吸铸法制备了Ti基非晶合金,并用渗流铸造法制备出孔隙率分别为30.86%、18.14%和15.28%的Ti基非晶合金/SiC陶瓷骨架复合材料。采用X射线衍射仪对纯Ti基非晶合金以及SiC陶瓷骨架复合材料进行相分析,确认了试件材料的非晶状态;在不同应变速率下,用分离式霍普金森压杆(SHPB)实验装置对试样进行室温轴向动态压缩力学性能测试,并利用能谱型场发射扫描电镜(SEM)等设备观察了试件的微观组织和断面特征,对比分析了Ti基非晶合金和SiC陶瓷骨架复合材料的动态压缩力学性能和失效机理。研究表明,Ti基非晶合金/SiC陶瓷骨架复合材料内部的微裂纹最初萌生于应力集中的两相界面处,并在SiC相内部或两相界面处扩展,继续加载,SiC相失效后,Ti基非晶合金相在远超过其动态压缩强度的应力下迅速失效,复合材料整体失效。SiC相内的断裂形貌主要有微裂纹与解理台阶,Ti基非晶合金相内的断裂形貌有脉状花样、多重脊状条带、蜂窝状花样与光滑无特征区,其中以光滑无特征区为主。复合材料的抗压强度随Si...     

Natural formation of a protective layer on copper and copper brazing in domestic water: structural characterization and electrochemical behaviour

The coupling Cu/Cu-P brazing, which is that most employed in domestic water supply pipes, has been investigated. Potentiostatic corrosion experiments were performed in domestic water under different conditions. It appears that the brazing has a better resistance than copper. The nature of the films formed at the sample surfaces was determined by various analysis techniques and the thicknesses were measured by ellipsometry. It was observed that it was the difference in composition of the films, formed at copper and brazing surfaces, which allowed the Cu-P brazing to become more noble than copper. The relatively thicker film formed on brazing, appears to contain mainly calcium carbonate and sulphate which grow epitaxially on calcium phosphate (hydroxyapatite or brishite). The corrosion resistance of the studied brazing was not only related to the galvanic coupling copper/brazing, but also depended on other parameters, mainly the water-flow velocity.     

烧结温度对单管式黄土陶瓷支撑体性能的影响

以中值粒径为38.78μm的洛川黄土为骨料,采用滚压成型法和固态粒子烧结法制备单管式黄土基陶瓷膜支撑体。探究烧结温度对黄土陶瓷支撑体性能的影响。通过热重分析、三点弯曲法、压汞法、自制装置、质量损失法、X-射线衍射、扫描电镜对单管式黄土基陶瓷膜支撑体的热稳定性、抗折强度、孔隙率、纯水通量、耐酸碱度、晶相组成的分析及表面形貌的观察对支撑体进行了表征。研究表明,烧结温度确实能影响黄土陶瓷支撑体的性能;当烧结温度为1100℃时,支撑体的表面光滑,孔隙率达到了20.08%、抗折强度为32.46 MPa、纯水渗透率为893 L/(m^2·h·MPa)、酸碱腐蚀重量损失率为0.42%与0.24%,平均孔径和中值孔径分别为4.68、2.68μm。在此烧结温度下可生产出成本合理、效果优良的陶瓷膜支撑体。     

Ceramic oxide bonds using calcium aluminosilicate glasses

Glasses with compositions falling in the Ca-Al-Si-O system are used to bond oxide ceramics. Alumina, zirconia and an alumina-zirconia composite are used as ceramic components. Joints are obtained at temperatures slightly higher than the melting temperature of glass which, for the selected compositions, change from 1210 to 1410°C. The degree of interaction between the ceramic components and the glass interlayer is mainly influenced by the bonding temperature and by the cooling rate. Conversely, the presence of defects like pores at the ceramic-glass interfaces depends on the experimental technique adopted to deposit the glass onto the ceramic surface. The 3-point flexural strength of the joint is measured at room temperature and for selected samples at 500°C. The mechanical properties of the joints are related to the microstructure at the interface.     

金属浴石油产品铜片腐蚀检测仪器的研制

为解决传统液体浴腐蚀仪器试验恒温时间长、控温误差大的问题,设计了一种基于金属浴温控技术的石油产品铜片腐蚀测定器。该仪器主要用于测定部分石油产品在特定温度下,对金属铜的腐蚀程度。试验结果表明该仪器温场波动小、加热均匀、工作效率高,可在石油产品铜片腐蚀试验中广泛应用。