溶胶－凝胶法合成YBa_2Cu_3O_（7－δ）／Ag_x的复合超导体研究

采用溶胶－凝胶法制得了ＹＢａ２ＣｕａＯ７－δ超细粉和Ａｇ２Ｏ细粉，用特定的烧结方法制各得了ＹＢａ２Ｃｕ３Ｏ７－δ／Ａｇｘ（ｘ＝０～９０％Ｖｏｌ）系列超导块体。研究了含Ａｇ量不同时的ＹＢａ２Ｃｕ３Ｏ７－δ相材料的烧结特性和渗流行为特征，以及对ＹＢ２Ｃｕ３Ｏ７－δ／Ａｇｘ体系的密度、Ｔｃ、Ｊｃ产生的影响．     

溶胶—凝胶法合成YBa2Cu3O7—δ／Agx的复合超导体研究

采用溶胶－凝胶法制得了ＹＢａ２Ｃｕ３Ｏ７－δ超细粉和Ａｇ２Ｏ细粉，用特定的烧结方法制备得了ＹＢａ２Ｃｕ３Ｏ７－δ／Ａｇｘ（ｘ＝０￣９０％Ｖｏｌ）系列超导块体。研究了含Ａｇ量不同时的ＹＢａ２Ｃｕ３Ｏ７－δ相材料的烧结特性和渗流行为特征，以及对ＹＢａ２Ｃｕ３Ｏ７－δ／Ａｇｘ体系的密试、Ｔｃ、Ｊｃ产生的影响。     

YBa2Cu3O7超导相的水解反应

超导相ＹＢａ２Ｃｕ３Ｏ７与水发生强烈反应．反应产物为ＣｕＯ，Ｂａ（ＯＨ）２和Ｙ２ＢａＣｕＯ５，并放出氧气．这主要是因为超导相中存在Ｃｕ３＋离子．环境中水气氛的存在将大大影响ＹＢａ２Ｃｕ３Ｏ７超导性．     

YBa_2Cu_3O_（7－δ）超导陶瓷螺旋谐振器

用ＹＢａ２Ｃｕ３Ｏ（７－δ）超导陶瓷裸线绕制了一定弹性和强度的螺旋谐振器内导体，整个ＹＢａ２Ｃｕ３Ｏ（７－δ）螺旋是导通和超导的。对比测试了室温和液氮温区下超导螺旋和同样尺寸Ｃｕ螺旋谐振器的品质因数（Ｑ），液氮温区（７７Ｋ、ｌ００ＭＨｚ）下，前者的Ｑ值比后者高３倍，初步显示了ＹＢａ２Ｃｕ２Ｏ（７－δ）高温超导体在这一领域应用的优越性。     

Sol－Gel法制备YBa_2Cu_3O_（7－x）超细粉末研究

用柠檬酸盐作螯合剂，用氨水调节溶液的酸度，通过Ｓｏｌ－Ｇｅｌ转变制得了粒径为１００ｎｍ大小的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末，对ＹＢａ２Ｃｕ３Ｏ（７－ｘ）在合成反应中溶胶的形成和凝胶聚合过程进行了研究和探讨。Ｓｏｌ－Ｇｅｌ法制得的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末在粒度、纯度、烧结特性和超导性能上，均优于固态反应合成方法。     

YBa2Cu3O7—δ超导陶瓷螺旋谐振器

用ＹＢａ２Ｃｕ４Ｏ７－δ超导陶瓷裸线制了一定弹性和强度的螺旋谐唇振器内导体，整个ＹＢａ２Ｃｕ３Ｏ７－δ螺旋是导通和超导的，对比测试了室温和液氮温区下超导螺旋和同样尺寸Ｃｕ螺旋谐振器的品质因数，液氮湿区下，前的Ｑ值比后高３倍，初步显示了ＹＢａ２Ｃｕ２Ｏ７－δ高温超导体在这一领域应用的优越性。     

热处理对YBa_2Cu_3O_（7－x）的J_c影响

论述了热处理温度、时间、气氛对ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－ｘ）的组织和Ｊ＿ｃ的影响，在氧气氛下热处理ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－ｘ）的效果比在空气下效果好．最佳热处理条件为：８７０℃，３小时，２个大气压纯氧条件下，Ｊ＿ｃ值可达１１４０Ａ／ｃｍ￣２。     

YBa_2Cu_3O_x超导相的生成机理的研究

通过控制烧结温度和冷却气氛的方法，合成了ＹＢａ２Ｃｕ３Ｏｘ的四种相——正交相－Ⅰ，正交相－Ⅱ，四方相－Ⅰ和四方相－Ⅱ，并对它们进行了鉴定，研究了四种相之间的相互关系，对超导相的生成机理进行了探讨。     

密封反应法制备HgBa2Ca2Cu3O8＋δ超导材料

对采用密封反应系统制备ＨｇＢａ２Ｃａ２Ｃｕ３Ｏ８＋δ超导材料的烧结工艺进行了探讨，采用多次短时热处理和快速升温的方法可避免了石英管的破裂并控制ＣａＨｇＯ２的生成，烧结后所得样品处于缺氧状态，Ｔｃ为１２０Ｋ氧化氛退火可使Ｔｃ升高到１３３Ｋ。     

电子—声子作用对氧化物超导电性的影响

考虑电子一声子作用对氧化物超导电性的影响，推导出级数型临界温度公式，计算出ＹＢａ２Ｃｕ３Ｏ６．８的超导临界温度，计算值和实验值较吻合。     

脉冲电子束系统沉积高温超导薄膜研究

高温超导薄膜生长是研究超导现象和超导器件的基础,一直是凝聚态物理研究的一个重要课题。各种各样的薄膜生长方法都被应用于高温超导薄膜的生长研究。采用一种崭新的薄膜沉积设备——脉冲电子束沉积系统(PED)成功制备出了NCCO、LSCO高温超导薄膜,并通过优化沉积参数,获得了具有良好表面形貌和超导转变特性的高温超导薄膜。     

3%C-Cu机械球磨复合粉末的烧结

为了给后续的致密化工序（如热挤压）提供较高质量的烧结坯,用扫描电镜和光学显微镜分析了3%C-Cu机械球磨复合粉末所制备烧结坯的显微组织,并研究了工艺参数对其相对致密度的影响规律。结果表明,烧结温度对未机械球磨混合粉烧结行为的影响很大,而机械球磨复合粉对烧结温度不敏感。真空热压烧结可以明显地促进致密化过程。提高烧结温度、延长烧结保温时间或增加热压压强,均有助于提高烧结坯的相对致密度。在相同条件下,烧结坯的相对致密度随着复合粉末机械球磨时间的延长而降低。     

Preparation and characterization of copper-nickel bulk nanocrystals

Copper-nickel nanoparticle was directly prepared by flow-levitation method(FL) and sintered by vacuum sintering of powder(VSP) method. Several characterizations, such as transmission electron microscopy(TEM), scanning electron microscopy(SEM), X-ray diffraction(XRD), differential thermal analysis(DTA), and energy-dispersive X-ray spectroscopy(EDX) were used to investigate the prepared nanostructures. The results of the study show that FL method could prepare high purity Cu-Ni nanocrystals of uniform spheres with size distribution between 20 and 90 nm. After sintering the bulk nanocrystalline copper-nickel has obvious thermal stability and the surface Webster hardness increases with the rising sintering temperature. At the temperature of 900 ℃, the specimen shows higher surface Webster hardness, which is about two times of traditional materials. When the sintering temperature arrives at 1 000 ℃ the relative density of bulk nanocrystals can reach 97.86 percent. In this paper, the variation tendency of porosity, phase and particles size of bulk along with the changing of sintering temperature have been studied.     

氮化铝陶瓷与铜界面传热计算机仿真

固体界面热阻是航空航天、低温与超导、微电子技术等领域中研究热点问题，氮化铝陶瓷和金属铜被广泛应用于低温超导装置和集成电路芯片。基于氮化铝陶瓷与金属铜样品之间界面热阻的低温实验，应用MATLAB软件对实验数据进行回归分析，建立了氮化铝陶瓷与铜之间界面热阻与温度、压力等参数的回归分析仿真模型，仿真结果与实验数据有较好的一致性。研究结果对氮化铝陶瓷、铜应用于超导装置和集成电路芯片的传热设计、空间热控制具有重要意义。     

Φ100mmY系高温超导靶材及制备工艺

本文利用固相反应成功地制备出直径Φ１００ｍｍ，厚度５ｍｍ的高质量超导靶材，超导靶材零电阻温度为９１Ｋ，同时对靶材原粉的要求和制靶工艺进行了分析。Ｘ射线衍射进行物相定性分析，扫描电镜进行形貌现察。用此靶材制备的超导薄膜，其零电阻温度在９０Ｋ，临界电流密度大于１０６／ｃｍ２，并用于制备超导电子器件。     

直接金属选区激光多道烧结温度场有限元模拟

局部输入的集中移动激光热源势必造成直接金属选区激光烧结过程中温度场分布不均匀、不稳定。研究多道激光烧结对掌握烧结过程中温度场动态分布及不同烧结道的相互影响规律具有重要意义。在考虑随温度变化而变化的热传导、比热容等热物性参数的作用下，建立直接金属多道烧结的三维温度场有限元模型。采用ANSYS参数化设计语言模拟多道烧结的热源移动，用焓处理相变潜热的影响。模拟结果显示：随着烧结过程的进行，随后的烧结道具有越来越大的热影响区域，且热影响区域的不均衡性越来越明显；极大的温度梯度发生在激光束扫描方向改变时的烧结件边沿区域。模拟结果的最高温度、平均温度与先前的实验结果一致。     

覆膜金属粉末变长线扫描激光烧结成型特性

介绍了利用变长线扫描激光烧结技术制造金属零件的基本原理。在线扫描激光烧结成型实验装置上对覆膜９８Ｆｅ２Ｎｉ合金粉末进行了烧结成型试验,研究了铺粉厚度、预热温度、激光功率、扫描速度及扫描方向等工艺参数对烧结成型性能的影响关系。     

Preparation of nanocrystalline BaTiO_3 ceramics

The high-dense nanocrystalline BaTiO3(BT)ceramics with grain size smaller than 100nm have been successfully prepared by the two step sintering and the spark plasma sintering(SPS)process.The successive transitions in nanograin BT ceramics from rhombohedral to orthorhombic,tetragonal and cubic transitions,similar to those in coarse BT ceramics,were revealed by in-situ temperature dependent Raman spectrum.The multiphase coexistence and the diffused phase transition character were demonstrated in the 8nm nanocr...     

Low-temperature sintering of FeCuCo based pre-alloyed powder for diamond bits

We studied the effects of sintering temperature on FeCuCo based pre-alloyed powder for diamond bits.The FeCuCo composite was fabricated by co-precipitation method.With the addition of tungsten carbide(WC),sintering under different temperatures was investigated.Mechanical properties of the FeCuCo based matrix were systematically studied.The structure of the composite was evaluated by X-ray diffraction(XRD) and scanning electron microscope(SEM) was used to analyze the surface of the powder and matrix.The suitable sintering temperature was determined through differential scanning calorimeter(DSC).Micro drilling experiments were performed,and 820 ℃ was identified to be the ideal sintering temperature,at which the matrix shows the best mechanical properties and drilling performance.     

Synthesis of TiN/AlON composite ceramics

The synthesis process of TiN/AlON composite ceramics was studied, the thermodynamics, mechanical properties and micro-structures of TiN/AlON have also been investigated. The TiN/AlON composite ceramics has been synthesized by both hot-pressing and pressureless sintering. The characterizations of the material synthesized were analyzed with XRD (X-ray diffraction) and TEM (transmission electronic microscope). The density and toughness strength of TiN/AlON are 3.57g/cm3 and 4.74MPa.m1/2, respectively. The bending strength was measured at both room temperature and high temperatures and the results are 399 MPa (room temperature), 406 MPa (1 073 K), 417 MPa (1 273 K) and 323 MPa (1 573 K). Pattern Recognition (PR) and Artificial Neural Network (ANN) were used to optimize the parameters and to predict the expected values. A proper parameter for pressureless sintering of TiN/AlON has been obtained and testified, the parameters are temperature (1 978 K), AlN / (AlN + Al2O3) ratio (0.22), MgO (4.7%) and TiO2 (7.2