Sialon及SiC陶瓷对金属摩擦副磨损性能的研究

为了使结构陶瓷能够在汽车发动机的某些摩擦副中得到应用,对Sialon(Si_3N_4基陶瓷)及SiC结构陶瓷对钢的摩擦副的摩擦磨损性能进行了研究。还作了钢对钢及冷激铸铁对钢的摩擦磨损性能的对比试验。结果表明:Sialon及SiC陶瓷对钢的摩擦系数比钢对钢及冷激铸铁对钢的摩擦系数小。在抗磨损性能方面,Sialon及SiC陶瓷试块即使在试验载荷比钢及冷激铸铁试块大的情况下,不但陶瓷试块的磨损量比金属试块的磨损量要小得多,而且与陶瓷试块相匹配的钢环的磨损量也比与金属试块相匹配的钢环的磨损量要小。用上述结构陶瓷材料制成汽车发动机中的某些零件以代替金属零件,不仅陶瓷零件本身耐磨性好,而且与陶瓷零件匹配的金属零件的磨损也会减小。     

反应烧结氮化硅陶瓷模具材料的研究

用反应烧结方法制备氮化硅陶瓷材料模具,然后将其安装在ＹＡ－１００型四柱液压拉深机上进行拉深不锈钢实验。结果证明：与水基润滑剂配合,反应烧结氮化硅陶瓷材料模具拉深ＳＵＳ３０４不锈钢时,拉深件不产生划痕、划伤等表面缺陷,拉深件废品低于０．１％模具表面也不产生拉深棱缺陷,是可以替代金属模具的新一代模具材料,开发前景广阔。     

利用复合烧结助剂改善氧化铝陶瓷力学性能初探

在复合助剂对氧化铝基陶瓷烧结性研究结果的基础上,本文继续就其力学性能进行观察,复合添加剂包括如下三部分物质：ＭｇＯ硅酸盐物质及过渡／稀土化合物,利用其综合叠加效应,在加入量不大的前提下（〈５％）不但较显著降低氧化铝陶瓷烧结温度,同时获得较好力学性能,实验发现,添加较少量（２％）硅酸盐物质材料既肯有良好的烧结性,又保证了较高强度在此特性基础上,研究了继续添加过渡／稀土化合物材料强度的影响,结果表明,     

压电陶瓷材料的研究现状与发展趋势

本主要概述了国内外关于压电陶瓷材料的发展历史进程和研究现状,探讨了其发展趋势和应用前景：指出了现代压电陶瓷材料正在向着复合化、薄膜化、无铅化及纳米化方向发展．应用前景广阔．是一种极有发展潜力的材料。     

原料杂质对ZTM陶瓷性能的影响及其排除

氧化锆增韧莫来石（ＺＴＭ）陶瓷可用电熔莫来石和高纯莫来石为原料制备，前者因原料中含有一定量的碱金属离子而使得陶瓷性能在高温下不象后那样呈现增长的趋势，要使工业电熔莫来石原料得到利用并改善陶瓷的性能，必面抑制或排除原料中杂质离子的作用，本文通过引入氧化硼添加剂，减弱了这些杂质离子的作用从而提高了该陶瓷的力学性能。     

Optimizing machining parameters to combine high productivity with high surface integrity in grinding silicon carbide ceramics

Advanced ceramics such as silicon carbide offer many desirable characteristics for industrial and commercial use in terms of their high temperature tolerance, wear and abrasive resistance, and corrosion resistance. However, the machining of ceramics into practical forms presents a challenge because of the difficulty and cost involved in the material removal process due to their high hardness and high brittleness. In this work, experiments were conducted to study the effect of various parameters such as depth of cut, table feed, size and density of grit on the metal removal rate, surface roughness, surface and subsurface damages. Mathematical models were developed using the data obtained experimentally considering the significant parameters only. Finally, a genetic algorithm (GA) code has been developed to optimize the ceramic grinding process with multiple objectives. The manufacturer׳s constraints on the basis of functional requirements of the component were also considered in the GA code. The study demonstrates that the grinding process parameters can be varied to achieve better metal removal rate, good surface finish and lower surface and subsurface damages simultaneously.     

探秘新型结构陶瓷材料及其运用与发展

先进的结构陶瓷材料由于具有一系列优异的性能,在节约能源、节约贵重金属资源、促进环境保护、提高生产效率、延长机器设备寿命、保证高新技术和尖端技术的实现等方面都发挥了积极的作用,受到业内的广泛关注。根据先进的结构陶瓷在工业工程中的应用效益显著,分析了先进结构陶瓷的主要组成物、性能特点及其应用领域,研究了先进结构陶瓷材料的新产品开发,介绍了先进结构陶瓷材料在发动机上的运用实例,同时指出了先进结构陶瓷材料的发展前景及趋势。     

NBT基无铅压电陶瓷的研究进展

由于环境保护的要求，无铅压电材料越来越受到关注，NBT基压电陶瓷是目前研究较多的一种无铅压电材料，采取各种掺杂措施可以提高其压电性能，获得具有实用价值的无铅压电陶瓷材料。     

室温固化硅酸盐耐高温防腐蚀涂料

制备了一种室温固化的硅酸盐耐磨防腐涂料,该涂料具有优异的耐磨防腐蚀性能,能广泛应用于金属、陶瓷、塑料、玻璃等材料表面,并且具有良好的附着力和匹配性,该涂料固化后还具有低的介电常数。     

Metal–Ceramic Composite Actuators

A new type of actuator composed of metal (brass) end caps and piezoelectric ceramics has been developed as a displacement transducer. Shallow cavities positioned between the metal caps and the central ceramic disk convert and amplify the radial displacement of the piezoelectric ceramic into a large axial motion of the metal end caps. Large d ₃₃ coefficients exceeding 2500 pC/N are obtained with the composite actuators. The behavior of the electrically induced strain with geometric variables, such as the thickness of the metal end caps, and with pressing force and driving frequency has been evaluated. Sizeable strains are obtained with both PZT (piezoelectric lead zirconate titanate) and PMN (electrostrictive lead magnesium niobate) ceramics.     

Phase stability,mechanical and thermodynamic properties of (Hf,Zr, Ta,M)B2 (M= Nb,Ti, Cr,W) quaternary high-entropy diboride ceramics via first-principles calculations

As the high-entropy design concept applied to the diboride ceramic system, high-entropy diboride ceramics with a wide range of composition control, is expected to become a new high-performance material for extreme high-temperature environments. Herein, the effects of four transition metal elements (Nb, Ti, Cr, W) on the phase stability and properties of (Hf, Zr, Ta)B₂-based high-entropy diboride ceramics are systematically investigated via the first-principles calculations. All components were identified as thermodynamically, mechanically and dynamically stable from enthalpy of formation, elastic and phonon spectrum calculations. Among these, compared with the (Hf, Zr, Ta)B₂ ceramics, the addition of Nb and Ti on the metal sublattice is beneficial to improve the mechanical properties of ceramics, including Young's modulus, hardness and fracture toughness, while the introduction of Cr and W weakens the strength of covalently and ionic bonds inside the material, reducing its mechanical properties. The predicted thermophysical properties show that the high-entropy diboride ceramics containing Nb and Ti have better high-temperature comprehensive performance, including higher Debye temperature, thermal conductivity and lower thermal expansion characteristics, which is conducive to the application in extreme high-temperature environments. This research will provide important guidance for the design and development of new high-performance high-entropy diboride ceramics.     

金属表面热化学反应法陶瓷涂层研究现状及工艺名称商榷

介绍了近几年新出现的热化学反应法陶瓷涂层技术,并将国内热化学反应法研究现状作了综述.依据该陶瓷涂层技术的反应实质,本文认为应称为"低温固相反应法陶瓷涂层技术".     

Processing Routes to Macroporous Ceramics: A Review

Macroporous ceramics with pore sizes from 400 nm to 4 mm and porosity within the range 20%–97% have been produced for a number of well-established and emerging applications, such as molten metal filtration, catalysis, refractory insulation, and hot gas filtration. These applications take advantage of the unique properties achieved through the incorporation of macropores into solid ceramics. In this article, we review the main processing routes that can be used for the fabrication of macroporous ceramics with tailored microstructure and chemical composition. Emphasis is given to versatile and simple approaches that allow one to control the microstructural features that ultimately determine the properties of the macroporous material. Replica, sacrificial template, and direct foaming techniques are described and compared in terms of microstructures and mechanical properties that can be achieved. Finally, directions to future investigations on the processing of macroporous ceramics are proposed.     

金属间化合物增韧陶瓷材料的效果与机理

金属间化合物作为结构材料近几年倍受众多研究者重视,但作为第二相物质与结构陶瓷形成复合材料的研究却相对较少.本文是一篇关于金属间化合物增韧陶瓷的综述文章,对重要的金属间化合物如Ni3Al,MoSi2等的性能特点,用其增韧Al2O3,Si3N4等陶瓷材料的效果、机理作了重点分析、评述.     

Reaction-based Processing of Textured Alumina by Templated Grain Growth

Highly textured, dense alumina ceramics were fabricated by a new processing route which utilizes a mixture of Al metal powder, alumina powder, alumina platelet (template) particles and a liquid phase former. The process involves dry forming the powder mixture (e.g. uniaxial pressing, and roll compaction) to align the plate-like template particles. The addition of a calcium aluminosilicate glass reduces constrained densification by the template particles and allows attainment of high density at ∼1450°C. The degree of orientation (i.e. r is 1 for a random sample and 0 for a perfectly textured material) and volume fraction of textured material, f, were measured by X-ray-based rocking curve technique and SEM-based stereological analysis, respectively. It has been shown that texture quality (the r parameter) is controlled by initial strain during forming, sintering time and temperature. In addition, alumina ceramics with the volume fraction of textured material ranging from 1 to ∼100% can be obtained.     

铁电陶瓷非线性本构行为的实验研究进展

由于铁电陶瓷优越的力电耦合性能,使其作为一种重要的功能材料被广泛应用于许多领域.它的非线性本构行为引起了研究者的广泛关注.本文首先介绍了铁电陶瓷非线性本构行为的一般特点及其微观物理机制.在此基础上,详细介绍了铁电陶瓷非线性本构行为的实验进展.最后,简要介绍了铁电陶瓷非线性本构实验的发展趋势.     

制备工艺和添加剂对TiO2体系陶瓷的复合功能特性的影响

TiO2体系复合功能陶瓷是一种兼有压敏功能和介电性能的新型功能陶瓷材料,具有压敏电压低、非线性系数高、介电常数大等优点,在微小型电子设备与器件中有广泛的用途。本文从制备工艺、添加改性等方面分析了TiO2体系复合功能陶瓷的研究现状,并对其发展方向进行了展望。     

Chemically Bonded Phosphate Ceramics: I, A Dissolution Model of Formation

This is the first of three papers in which the kinetics of formation of chemically bonded phosphate ceramics is discussed. A literature survey indicates that the formation of such ceramics is a three-step process. First, oxides dissolve in a phosphoric acid or an acid phosphate solution and metal ions are released into the solution. The aquoions formed from these cations then react with phosphate anions and form a gel of metal hydrophosphates. In the last step, the saturated gel crystallizes into a ceramic. In this paper, we have proposed that the dissolution is the controlling step and developed a general dissolution model of the kinetics of formation of these ceramics. As an example, the model is used to discuss the kinetics of formation of magnesium phosphate ceramics in detail. In the second and third papers, the model has been used to develop processes to form ceramics of alumina and iron oxides.     

吸波材料研究进展

简述了吸波材料的吸波物理机理、吸波特性、吸波材料分类以及吸波材料的应用领域。并结合实际指出多晶金属纤维、SiC基陶瓷和C／C复合材料是目前性能最佳、应用前景最好的电磁波吸收材料。     

通信用片式介质陶瓷双工器的设计与制作

介绍了通信用介质陶瓷双工器的设计方法和制作过程。该双工器是由接收滤波器和发射滤波器组成的。每种滤波器是由一块高介电常数、高Q值和接近零温度系数的介质陶瓷块制成的。这个陶瓷块上包含两个四分之一波长同轴谐振腔、输入及输出电极和耦合装置,并且输入及输出电极在陶瓷块的同一侧面上,因此滤波器具有体积小巧,结构稳定和安装方便的特点。采用介电常数为90的陶瓷材料制作了中心频率分别为903MHz和927MHz的接收和发射滤波器,经网络分析仪测试,各项技术指标满足设计要求。