复合造孔剂对刚玉-钙长石-莫来石系轻质浇注料性能的影响

本文以聚苯乙烯小球和炭黑作为复合燃烬添加物,研究复合造孔剂对刚玉-钙长石-莫来石系轻质浇注料性能的影响,并确定了聚苯乙烯小球和炭黑复合的最佳掺量.采用XRD分析了轻质浇注料的物相组成.结果表明:轻质浇注料的主要矿物相是刚玉、钙长石、莫来石和少量玻璃相,随着聚苯乙烯小球和炭黑加入量的变化,轻质浇注料的力学性能得到明显改善...     

成型工艺对莫来石质隔热耐火砖性能的影响

为了探索不同成型工艺对莫来石质隔热耐火砖性能的影响,实验分别以机压法、挤出法和泡沫法三种方式制备莫来石轻质隔热材料,并对其性能进行了研究。实验结果表明:采用泡沫法制备的莫来石质隔热耐火砖具有隔热效果好、荷重软化温度高、强度好、重烧线变化率小等优点。     

高温箱式电炉炉顶、炉壁预制块的研制与应用

高温箱式电炉主要用来进行固体原料烧结、坯体烧成、熔炼及耐火材料制品检验的重要专用设备.随着高温箱式电炉炉容及使用温度的增加,电炉炉顶、炉壁用耐火材料已经成为制约电炉使用的重要因素.传统箱式电炉炉顶采用刚玉质或刚玉莫来石质轻质砖整体搭接或对接而成,而炉壁采用刚玉质或刚玉莫来石质轻质砖,经人工切割砌筑而成,炉体结构的整体性较差,尤其对于大容量箱式电炉,炉体采用耐火砖对接方式砌筑,容易产生炉顶耐火砖掉角、脱落,甚至炉体温度过高,热量损失严重的情况.     

添加Li2O对高铝粉煤灰合成刚玉-莫来石材料的影响

研究了Li2O、烧结温度对高铝粉煤灰和铝矾土合成刚玉-莫来石材料的性能、物相组成和显微结构的影响.结果表明,Li2O可大辐度降低合成刚玉-莫来石材料的烧结温度.制得的刚玉-莫来石材料具有较良好的性能.     

硅溶胶对刚玉莫来石复相陶瓷的性能影响

采用溶胶-凝胶法在刚玉-莫来石质材料中引入活性硅溶胶(SiO2),分析了硅溶胶对刚玉-莫来石复相陶瓷性能的影响机制。研究结果表明,SiO2在主体材料中形成纳米包裹薄膜,SiO2的分布可控、掺入均匀,从而提高了复相陶瓷的抗热震性、高温强度及蠕变性。加入SiO2溶胶产生的莫来石反应化和微裂纹增韧是刚玉-莫来石质材料热震稳定性提高的主要原因。     

电熔致密刚玉和板状刚玉对刚玉-莫来石材料结构与性能的影响

以电熔致密刚玉、板状刚玉、电熔莫来石、可引入硅源和铝源的复合粉体为主要原料,研究了电熔致密刚玉和板状刚玉对烧后(1600、1700℃)刚玉-莫来石材料结构与性能的影响.结果表明:1)电熔致密刚玉的反应活性较低,原位莫来石缓慢持续生成,晶粒数量较少、尺寸较大,而板状刚玉的反应活性相对较高,原位莫来石晶粒数量较多、尺寸较小...     

玉米淀粉造孔剂对富铝煤矸石合成轻质莫来石料的影响

为了综合利用煤矸石,以天然富铝煤矸石矿为原料,聚乙烯醇(PVA)为结合剂,玉米淀粉为造孔剂,于1 500℃保温3 h反应烧结合成轻质莫来石料,研究了造孔剂加入量(其质量分数分别为10%、20%、30%、40%、50%)对轻质莫来石烧结性能以及显微结构的影响。结果表明:随着玉米淀粉加入量的增大,合成的轻质莫来石料体积密度明显降低,显气孔率和线收缩率显著增大,玉米淀粉的添加量以40%(w)为宜,此时合成的轻质莫来石料的体积密度和显气孔率分别为1.21 g·cm-3和62%;合成的轻质莫来石料的主晶相为莫来石,次晶相为刚玉,莫来石晶体呈柱状发育,刚玉晶粒被莫来石晶粒包裹,构成了疏松的空间网络结构。     

烧成制度对刚玉-莫来石陶瓷相含量、显微结构及性能的影响

本文介绍了采用挤出成型工艺制备结构陶瓷的过程,研究烧成制度对刚玉-莫来石结构陶瓷微观结构、相变反应及性能的影响。结果表明:当升温速率较快时,刚玉固溶和溶解速度较慢,残余刚玉量较高,生成玻璃相较少;随着温度升高,刚玉与莫来石的相对质量比越来越小,说明提高温度,加速了刚玉溶解,但是玻璃相/莫来石比值不同,更易受升温速率影响,快速升温时温度越高,比值越小,慢速升温时温度越高则比值越大;升温速率对莫来石、刚玉和玻璃相作用因子从大到小排列顺序是:玻璃相刚玉莫来石,快速升温时最高温度影响因子排列顺序是:玻璃相莫来石刚玉,慢速升温时最高温度影响因子是:玻璃相刚玉莫来石;1550℃以下烧成莫来石生长发育不良,晶体出现短柱状长径比较小,网状交叉分布数量明显减少,气孔较多,这是因为二次莫来石化未完全反应,未充分烧结;结构陶瓷热膨胀系数影响因子:刚玉与莫来石质量比、显气孔率、体积密度,其中刚玉与莫来石质量比是最主要影响因素,后两者影响作用比较接近,刚玉与莫来石质量比越大,陶瓷热膨胀系数则越大。     

蓝晶石含量对轻质莫来石-刚玉浇注料显微结构与性能的影响

为了改善含球形莫来石轻骨料的轻质莫来石-刚玉浇注料的体积稳定性及抗热震性,以球形莫来石轻骨料(≤1、1~2和3~4 mm)、板状刚玉细粉(≤0.074 mm)、广西白泥(≤0.045 mm)、Secar 71水泥(≤0.088mm)和蓝晶石(≤0.5 mm)为主要原料,研究了蓝晶石含量(加入质量分数分别为0、4%、6%、8%、10%和12%)对轻质莫来石-刚玉浇注料显微结构与性能的影响。结果表明:经1 500℃热处理后,随着蓝晶石含量增加,试样由显著收缩变为显著膨胀,体积密度减小,显气孔率增大,常温强度降低;基质中小气孔含量(≤10μm)逐渐减小,大气孔孔径及含量逐渐增大;抗热震性先变好后变差。综合考虑各项性能,蓝晶石含量为6%(w)试样的综合性能最佳:体积密度为1.96 g·cm~(-3),显气孔率为37.1%,常温抗折强度为10.8 MPa,常温耐压强度为43.8 MPa,加热永久线变化率为0.07%,弹性模量保持率为42.9%,800℃热导率为0.60 W·(m·K)~(-1)。     

锆英石添加莫来石／刚玉材料的制备及性能研究

本文以莫来石／刚玉材料为基体，以锆英石为添加剂制得莫来石刚玉材料，通过SEM，XRD等测试分析了材料的体积密度，抗折强度，抗热震性。讨论了锆英石的加入量对莫来石刚玉显微结构和材料性能的影响。研究结果表明，锆英石加入量为4％-6％的莫来石-刚玉材料具有较高的抗折强度和优良的耐热震性。     

工艺参数对石英质多孔材料孔性能的影响

以长江沿岸低品位石英砂为主要原料,采用真空烧结制备了石英质多孔材料。通过实验分析发现:随烧结温度的升高、水料比的增大或发泡剂含量的增加,多孔材料的气孔率增大,抗压强度降低;而随着保温时间的延长,多孔材料的气孔率降低,抗压强度升高。通过优化得出最佳配比为:石英砂60 wt%、高岭土30 wt%、助烧剂9.6 wt%、发泡剂0.4 wt%。按这一最佳配比配料,在水料比为0.9的条件下球磨2 h制浆发泡,而后在1175°C烧结1 h,可以制备得到性能较佳的石英质多孔材料。     

Evaluation of cathode material properties relevant to the life of Hall-Heroult cells

Proper start-up procedures and operation are extremely important for a satisfactory life of an aluminium reduction cell, but the thermomechanical and chemical properties of cathode materials relative to the design of the lining may lead to failure in an otherwise normally operated cell. The producers of cathode materials (carbon blocks, ramming paste, firebricks and insulation) usually characterize their materials well with respect to room temperature properties but it is also important to have a good understanding of materials properties under actual start-up and electrolysis conditions. Towards this goal we have adapted, improved or developed test methods which we consider important as design tools as well as for quality control of the materials. Examples of materials properties and designs that may lead to failures are given.Paper presented at the meeting on Materials Problems and Material Sciences in Electrochemical Engineering Practice organised by the Working Party on Electrochemical Engineering of the European Federation of Chemical Engineers held at Maastricht, The Netherlands, September 17th and 18th 1987.     

Properties of piezoceramics produced from lead zirconate-titanate powder obtained by plasma denitration

The effect of the sintering conditions on the properties of piezoceramic materials made of lead zirconate-titanate obtained by the plasma denitration method is demonstrated. The optimum sintering conditions for piezoceramic materials providing the maximum values of the electrophysical parameters are determined.     

PE-UHMW微孔滤材成型工艺研究

采用烧结法制备了超高相对分子质量聚乙烯（PE-UHMW）微孔材料,并对微孔材料的各项性能进行了分析。结果表明,采用烧结法成型的PE-UHMW粉末的颗粒与颗粒间相互堆砌,堆砌形成的间隙便是微孔形成的原因。微孔材料的性能与PE-UHMW的相对分子质量、粉末粒径、堆砌密度、烧结温度、烧结时间等因素有关。PE-UHMW的相对分子质量越大,微孔材料的压缩强度越大;粉末粒径越大,微孔材料的孔径越大;随着烧结温度和烧结时间的增加,微孔材料的孔径变小,孔径分布变宽。     

Effect of Granite Screenings on the Properties of Acid-Resistant Materials

The effect of a fluxing additive in the form of granite screenings on the physicotechnical properties of acid-resistant materials produced on the basis of high-melting clay was investigated. The effect of the vitreous phase on the sintering process and the main properties of coarse-grained acid-resistant materials is demonstrated.     

四喷嘴对置式气化炉耐火砖侵蚀原因分析与改进

针对宁波万华聚氨酯有限公司气化炉耐火砖使用情况,分析了耐火砖侵蚀的原因。气化炉内不同部位耐火砖侵蚀速率与其所处流场位置有关;其侵蚀机理分为物理侵蚀和化学侵蚀,物理侵蚀包括新耐火砖的养护阶段损伤、高温火焰、气体及炉渣的直接冲蚀,化学侵蚀包括炉渣CaO酸性组分侵蚀、还原性气体侵蚀等。在此基础上,总结了宁波万华气化炉运行中耐火砖出现的问题和改进措施,以供参考。     

A review of two-step sintering for ceramics

The development of high-density ceramic materials with fine-grained microstructures has been studied to considerably improve their properties for high-performance applications. Many alternatives have been searched to refine their microstructure by changing their composition and/or processing. Among such alternatives, the densification of ceramic materials by sintering curve control is an effective, simple and economical microstructure refinement method. Thus, different thermal treatment techniques such as spark plasma sintering and microstructural forms of control such as the control of sintering conditions have been used to obtain nanostructured materials. One of the techniques widely used in recent years is two-step sintering. Two-step sintering (TSS) is a promising method used to obtain high-density bodies and smaller grain sizes. Two TSS methodologies are known: sintering with thermal pretreatment at a low sintering temperature, followed by a second stage at elevated temperature, and the more recent approach presented by Chen and Wang, which has been the most widely used. In addition to the sintering conditions (temperature, heating rate and sintering holding times) that must be suitable for each composition type, the starting materials, particle size and processing method may influence the obtained microstructure, especially the reduced grain size and increased densification. The current review of two-step sintering presents the effect of this technique on the grain density and sizes of different ceramic materials. The influence of the addition of doping agents and its effect on the mechanical properties in different systems is also presented in the current study.     

利用赤泥制备琉璃瓦

本文利用广西平果铝厂产出的工业废弃物———赤泥制备琉璃瓦,研究琉璃瓦的坯料配比及坯料的可塑性,以及釉料的组成,为赤泥的开发利用开辟一条新途径。     

利用赤泥制备琉璃瓦的研究

利用广西平果铝厂产出的工业废弃物—赤泥制备琉璃瓦,研究琉璃瓦坯料的配料比及坯料的可塑度,以及釉料的组成,为赤泥的开发利用开辟了一条新途经。     

磷酸锆基陶瓷材料的制备与性能研究

利用共沉淀法制备了磷酸锆，用差热分析法（DTA）研究了Zr2P2O7的热稳定性情况，并进一步研究了烧结助剂的量、烧结温度等对其性能的影响。