含Co、Ni、Fe锂铝硅玻璃的析晶机制

以Li2O-Al2O3-SiO2（锂铝硅）微晶玻璃为研究对象,采用DTA、XRD、IR和SEM等测试技术研究含Fe2O3、Co2O3、Ni2O3锂铝硅玻璃的析晶动力学和晶化过程,分析着色剂成分Co2O3、Ni2O3对锂铝硅玻璃晶化过程及结构的影响机制。结果表明：着色剂成分不仅决定锂铝硅微晶玻璃的着色度,而且还影响锂铝硅玻璃的析晶过程和显微结构;着色剂的加入可提高锂铝硅玻璃的析晶温度,但降低析晶动力学参数,且高Co2O3含量的降幅大于高Ni2O3含量的。着色剂对锂铝硅玻璃析晶能力的影响主要与着色离子的离子半径、电场强度及对断裂硅氧四面体联结能力有关。     

离心法制备氧化铝-氧化锆泡沫陶瓷过滤器

通过在发泡聚苯乙烯模板内的离心成型方法来制备Al2O3-ZrO2泡沫陶瓷过滤器,测量了浆料在不同pH值下的Zeta电位,分析了浆料的固相含量对离心时间的影响。观察了不同离心加速度和浆料固相含量下产物生坯密度的变化,测量了最终产物的烧结密度、收缩率、孔隙率和压缩强度,并通过扫描电镜观察了烧结试样的显微结构。试验结果表明,在pH=10时,浆料具有较好的分散性。在较低的固相含量和较高的离心加速度下,浆料的分离现象明显,生坯中出现密度梯度。但在高的固相含量(50%,体积分数)下,分离现象被抑制,孔筋具有较高的生坯密度(61.5%)和烧结密度(91.1%),最终产物的孔隙率在75.3%～83.1%,压缩强度为2.07～3.82 MPa。     

采用聚硅氮烷制备SiCN泡沫陶瓷

采用含乙烯基聚硅氮烷为原料，利用先驱体转化法与有机泡沫浸渍法相结合制备SiCN泡沫陶瓷。通过聚氨酯泡沫及聚硅氮烷的热分析制定温度曲线，研究了裂解温度、浸渍／裂解增强处理次数等工艺参数对泡沫陶瓷抗压强度的影响，采用XRD、SEM及EDS对SiCN泡沫陶瓷进行了物相、微观结构及成分分析。结果表明，在1000～1400℃温度范围内，随着温度的升高，泡沫陶瓷的抗压强度先升高后降低，增强处理对提高抗压强度有明显效果，当裂解温度为1300℃，经二次增强处理后，试样的抗压强度达11．5MPa。XRD研究表明，随着温度的逐步升高，聚硅氮烷的裂解产物发生了由非晶态向晶态的转变。微观结构分析显示，SiCN泡沫陶瓷呈三维网状结构，具有良好的贯通性，开孔气孔率达到85％。     

The oxidation of nanocrystalline Ni3Al fabricated by mechanical alloying and spark plasma sintering

Nanocrystalline Ni₃Al was fabricated through mechanical alloying of elemental powders and spark plasma sintering. The nanocrystalline Ni₃Al has a nearly full density after being sintered at 1223 K for 10 min under a pressure of 65 MPa. Isothermal and cyclic oxidations of nanocrystalline Ni₃Al were tested at 1173–1373 K with intervals of 100 K. The results indicate that nanocrystalline Ni₃Al exhibits excellent isothermal and cyclical oxidation resistance. The oxide scales consist primarily of dense and continuous -Al₂O₃. The grain refinement is beneficial for improving the oxidation resistance of Ni₃Al by providing more nucleation centers for the Al₂O₃ formation, promoting the selective formation of Al₂O₃ and improving the adhesion of oxide scales to the matrix.     

Influence of Plasma Instabilities in Ceramic Suspension Plasma Spraying

Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

Reticulated Porous Multiphase Ceramics with Improved Compressive Strength and Fracture Toughness

A multiphase reticulated porous ceramic (RPC) as Si₃N₄–Al₂O₃–SiO₂ was fabricated by replication techniques. Proper volumes of additives and twice sinter- twice immerse process endow the RPC an excellent crack healing and submerging property. The compressive strength and fracture toughness improved owing to the crack bridging behavior. The existence of pores in struts in RPC blunt the crack tip and increased the external force needed to propagate the crack. The mechanisms play a beneficial role in enhancing the compressive strength and fracture strength. Si₃N₄ RPC with additives of 5%Al and 5% Al₂O₃ yielded the compressive strength of 9.8 MPa and fracture toughness of 0.3 MPa m^1/2.     

基于状态维修的设备管控一体化系统研究

针对当前企业设备管理体制的弊端,提出了状态维修体制与计划预防维修体制相结合、设备管理与控制相结合的设备管控一体化方法,建立了状态监测、故障诊断、设备管理集成的设备管控一体化系统,分析了设备管控一体化系统的功能,提出了系统实现的一些关键技术并指出了系统在企业的应用中存在的问题.     

扩散处理对Si3N4陶瓷与金属钎焊接头的强化作用

用扫描电子显微镜、能谱仪及X射线衍射仪分析和讨论了复合电镀Ni-Ti陶瓷与金属钎焊接头的强度、微观结构和其界面结合机制。试验表明：扩散处理对陶瓷与金属钎焊接头有强化作用。经辉光扩散处理后，Ti向陶瓷界面扩散，Ni-Ti层与陶瓷发生界面反应。     

微等离子体氧化陶瓷膜对钛合金接触腐蚀的影响

在铝酸钠溶液中，利用微等离子体氧化技术，在TC4钛合金表面原位生长复合氧化物陶瓷膜，研究了陶瓷膜的相组成、形貌和陶瓷膜对钛合金接触腐蚀的影响。陶瓷膜由Al2TiO5，α-Al2O3和RutileTiO2构成；整个膜层由致密层和疏松层组成。陶瓷膜层改善了钛合金与LY12铝合金和H62黄铜的接触腐蚀，陶瓷膜层使得钛合金与LY12铝合金电偶对的电偶电流降低为原来的1／7，使得钛合金与H62黄铜的电偶电流降低为原来的1／2。     

Al2O3/Ti生物相容连接接头微观组织及力学性能

文中对Al₂O₃陶瓷和金属Ti表面磁控溅射Mo和Ti金属层,以纯Au箔钎料,研究连接工艺及Ti金属化层厚度对连接接头微观组织和力学性能的影响.结果表明,焊缝主要由Au钎料和（Au,Mo） ss构成,（Au,Mo） ss中含有少量（Ti,Mo） ss和TixAuy金属间化合物.另外,在Al₂O₃/钎料界面处及焊缝中存在少量呈条状分布的TiO₂和Ti_xAl_y金属间化合物.连接工艺及Ti金属化层厚度主要影响各物相的数量及分布状态,通过影响焊缝中固溶体的分布均匀性及金属间化合物的数量而影响接头抗剪强度.当连接温度为1 080℃、保温时间为5 min、Ti金属化层厚度为0.2 μm时,接头的抗剪强度达到最大值138 MPa.