氧化铝的气力输送

着重介绍了氧化铝的几种气力输送形式，输送机理，主要输送设备，在生产中的应用及技术经济指标比较。     

氧化铝陶瓷内衬复合钢管的组织结构与质量控制

在分析陶瓷内衬复合钢管组织结构特点的基础上,讨论了复合管存在的主要质量缺陷,提出了改善复合管质量的控制措施。     

氧化铝在精细陶瓷中的应用

氧化铝是精细陶瓷的重要原料之一。本文介绍了氧化铝粉体制作方法,烧结技术;氧化铝在基片、发光管、传感器、生物、固定化酶载体、航空航天耐热结构材料、刀具、催化剂载体和机械零件中的应用。     

陶瓷树脂内衬复合钢管介绍

采用树脂材料密暑离心铝热法制备陶瓷瓷钢管内衬层气孔，从而获得具有防护耐磨双重功能的复合管材。产品内衬层与钢管基体结合强度高，可在真空状态下长期运行，在高温下内初不鼓泡、不折皱。     

氧化铝基复合陶瓷物理和力学性能的研究

采用热压烧结致密化工艺,在1550,1600,1650℃3个不同的烧结温度下,烧结制备了Si3N4含量从O．25w％到6w％的A1203／Si,N。纳米复相陶瓷。对所制备的试样进行了密度、硬度、断裂韧性的测试。实验结果表明,所有试样达到了较高的致密度,且致密度随烧结温度的升高而增加。硬度在Si3N。含量为0．75w％和3w％时达到峰值。韧性在Si3N4含量3w％达到峰值。材料的性能较纯A120,陶瓷有较大幅度提高。     

氧化铝陶瓷低温特性研究

研究了α-Al2O3含量分别为99%和92%的氧化铝陶瓷(以下分别简称99和92氧化铝陶瓷)在室温和低温下(293,195和77K)的力学和热学性能。结果表明:两种氧化铝陶瓷的抗弯强度变化规律相同且变化幅度都较小,说明玻璃相的存在并没有对氧化铝的低温强度造成显著影响;99氧化铝的断裂韧性随温度降低线性升高,而由于晶界玻璃相的存在,92氧化铝的断裂韧性在77K时有所降低。热学性能测试表明,两种氧化铝的热导率随温度的变化规律一致。99和92氧化铝在20K时的热导率分别为4.1和1.7W/(m·K),远远小于不锈钢的热导率14.7W/(m·K)。因此,如果采用氧化铝陶瓷替代不锈钢作为超导绝缘支撑材料可以大大降低系统的漏热,提高超导磁体的稳定性。     

复相添加剂／3Y-TZP复合增韧氧化铝陶瓷的研究

利用复相添加剂和3Y-TZP的叠加作用，对氧化铝陶瓷的增韧机制和途径进行了研究。结果表明：复相添加剂有助于Al2O3／3Y-TZP复合材料中氧化铝晶粒的异向生长，其增韧效果与3Y-TZP产生了叠加效应。实验材料密度接近理论密度；抗弯强度556．35MPa；断裂韧性6．73MPa．m^1/2；综合力学性能明显提高。     

SHS陶瓷内衬复合钢管的研究进展

自蔓延高温合成陶瓷复合钢管技术是20世纪90年代发展起来的高新技术，陶瓷内衬复合钢管具有良好的耐磨、耐蚀、耐热性能，可广泛应用于化工、冶金、矿山等许多工业部门。从设备、工艺、各种不同复合管研究的角度总结了近年来在这一技术领域的研究成果。     

物料因素对氧化铝超浓相输送影响的探讨

通过对中铝青海分公司电解一期、三期氧化铝超浓相输送情况的分析，探讨了物料因素对超浓相输送的影响。     

氧化铝粉的压送式气力输送

介绍了气力输送系统分类、使用现状与特点,并且概述了提高气力输送系统效率的设计方法。最后通过实例分析了气力输送系统参数的计算与选取。     

氧化铝输送方式的选择

阐述了氧化铝输送方式的优缺点,认为在选择和确定氧化铝输送方式时,首先满足输送量、输送距离等主要输送条件参数的要求,且同时要考虑能耗和经济性等问题。给出了输送方式改造应用实例,改造后的流程带来了可观的经济效益。在设计阶段根据实际情况和条件充分考虑各种氧化铝输送的特性,才能选择一个最佳的氧化铝输送流程。     

氧化铝陶瓷疲劳损伤过程的数字描述

用非对称正弦波动态载荷变化的方式跟踪了不同粘土结合剂添加量对利用铝型材厂废渣合成的氧化铝陶瓷的疲劳损伤过程的影响,用系统分析方法定义的疲劳损伤参数作为主要评价指标,结合试样的晶相结构和显微结构分析讨论了影响氧化铝陶瓷疲劳特性的因素,确定了最佳的结合剂添加量.结果表明,影响氧化铝陶瓷疲劳寿命的主要因素为试样中玻璃相的含量,当粘土添加量为18%时,试样的裂纹萌生寿命达到最高,为22500周,此时,体系内刚玉相含量为75%,玻璃相含量为20%.     

烧结温度对氧化铝陶瓷疲劳损伤过程的影响

用在线定量分析方法跟踪了不同烧结温度对利用铝型材厂废渣合成的氧化铝陶瓷的疲劳损伤过程的影响,同时结合试样的XRD和SEM分析结果,确定了影响氧化铝陶瓷疲劳特性的主要因素.结果表明,1450℃烧成的试样的疲劳裂纹萌生寿命最高,达到6100周,此时体系内玻璃相含量约为30%,晶相含量约为70%.其中玻璃相含量的高低是决定氧化铝陶瓷疲劳特性的主要因素.     

Al_2O_3陶瓷基片电子封装材料研究进展

总结微电子封装技术对封装基片材料性能的要求,介绍Al2O3的多晶转变和典型性能,讨论超细Al2O3粉体的3种制备方法:固相法、气相法和液相法;分析Al2O3陶瓷常用烧结助剂的基本作用和Al2O3陶瓷常用的6种烧结方法:常压烧结法、热压烧结法、热等静压烧结法、微波加热烧结法、微波等离子烧结法和放电等离子烧结法;指出Al2O3陶瓷基片的发展方向。     

Application of the FITSC method for characterization of PZT-type ceramics with the diffuse phase transition

In the present work the (Pb_0.84Ba_0.16)(Zr_0.54Ti_0.46)O₃ (PBZT 16/54/46) ceramics has been studied from the point of view of its electrical properties. Dielectric properties of PBZT were measured within the temperature range of the ferroelectric-paraelectric (FE-PE) phase transition region. The method of field-induced thermally stimulated currents (FITSC) was applied and thus the thermal relaxation effects were studied. The observed field dependence of thermally stimulated depolarization currents has revealed the existence of different frequency-dependent relaxation processes in the temperature range between 200 and 400 °C.Our experiment demonstrates that modification of ferroelectric materials with isovalent ions, but bigger radii than the origin atom, significantly affect its properties, particularly the PBZT real part of electrical permittivity shows the phase transition character change from ferroelectric to relaxor and finally, that electrical examination can be effectively used for drawing decisive applications conclusions considering polarization parameters distribution.     

Alumina-base plasma-sprayed materials part I: Phase stability of alumina and alumina-chromia

Aluminum oxide is a relatively cheap, abundant material that is widely used for plasma- spray applications. This material, however, exists in many crystallographic modifications with different properties. In addition, most of these modifications are metastable and cannot be used in applications employed at elevated temperatures. Usually γ, δ, or other phases form after spraying, while α phase (corundum) is often the most desirable phase due to high corrosion resistance and hardness. This paper first reviews the method of α stabilization in the as- sprayed materials offered in literature. Then, as an example, it summarizes the results of an extensive study of chromia additions to alumina. Chromia was chosen because of its complete solid solubility in alumina and its crystal lattice type, which is similar to that of alumina. It was demonstrated that the addition of approximately 20 wt% chromia results in the formation of one solid solution of (Al- Cr)₂O₃ in the α- modification. Finally, this paper discusses the thermal stability of various alumina phases. Phase change routes of heating for different starting alumina modifications are discussed, and a case study of alumina- chromia is presented. Both types of as-sprayed structures, a mixture of α, δ, and γ phases, and 100% (Al- Cr)₂O₃ were annealed up to 1300 °C and the phase composition checked. At lower temperatures and shorter holding times, the amount of α phase decreases while another metastable θ phase appears, and the fraction of γ + δ, if present, increases. At temperature above 1100 °C, the amount of α phase increases again.     

In situ synthesis and phase analysis of low density O'-sialon-based multiphase ceramics

In situ formed low density O'-sialon-based multiphase ceramics were prepared by liquid-phase sintering method at 1400°C with Si3N4, SiO2 and Al2O3 as raw materials.Crystalline phases were identified by X-ray diffraction(XRD).The quantitative phase analysis was finished by matrix-flushing method and the substitution parameter x value of O'-sialon was estimated.The effects of sintering additives on the phase composition of the material were studied.The results show that, when using Y2O3 alone, Al6Si2O13 phase...     

微波烧结ZrO_(2(n))/Al_2O_3复合陶瓷工艺与组织

以纳米ZrO2、微米Al2O3为原料,采用微波烧结方式制备ZrO2/Al2O3复相陶瓷。探讨了烧结温度和保温时间对试样线收缩率、相对体积密度、硬度和断裂韧性的影响。结果表明,烧结温度1550℃,保温时间10 min,可得到较高的硬度(13 350 MPa)和较好的断裂韧度(6.41 MPa.m1/2),烧结过程中发生了m-ZrO2转变为t-ZrO2相变,nano-ZrO2的加入使Al2O3形成內晶型结构;试样的断裂方式为沿晶断裂和穿晶断裂并存;ZrO/AlO复合陶瓷主要通过应力诱导相变和内晶型结构进行增韧。