钛酸铝陶瓷及其应用

本文对钛酸铝陶瓷的结构、热稳定性、微裂纹、低热膨胀性、机械强度及应用进行了综合阐述,并对工艺条件及添加剂对钛酸铝陶瓷性能的影响进行了讨论,给出了改善钛酸铝陶瓷性能的方法和途径,最后提出了钛酸铝陶瓷的研究开发方向。     

改善钛酸铝陶瓷机械强度和热稳定性的途径

钛酸铝陶瓷是集热膨胀系数低和熔点高二大特点于一体的新型陶瓷材料。纯的钛酸铝材料其室温至1000℃内的热膨胀系数比熔融石英(0.5×10K~(-1))还低。而熔点高达1860±1、0℃是目前低膨胀材料中耐高温性能最好的一种,此外钛酸铝还具有耐蚀、抗渣及耐碱等许多特性。但由于它存在机械强度低、难致密烧结和低温分解等本身固有的缺陷,因此自1932年发现钛酸铝以后很长的一段时间里,对它的研究进展相当缓慢,真正使之付诸工业应用也不过是近十年来的事情。现在在国外钛酸铝陶瓷已被广泛应用于钢铁、汽车、化学及军事等工业,而国内关于它的研究还处于初级阶段,尚未工业应用。所以正确认识钛酸铝的微观结构与其宏观结构的关系,明确提交钛酸铝低嘭胀陶瓷机械强度和热稳定性的途径,对赶超国际先进水平,实现我国钛酸铝陶瓷的广泛实际应用具有十分重要的意义。     

钛酸铝陶瓷的性能及其应用

本对钛酸铝陶瓷的结构、热稳定性、微裂纹、低热膨胀性、机械强度及应用进行了综合阐述,并对工艺条件及添加剂对钛酸铝陶瓷性能的影响进行了讨论,给出了改善钛酸铝陶瓷性能的方法和途径,最后提出了钛酸铝陶瓷的研究开发方向。     

钛酸铝陶瓷及其研究现状

本文简述了钛酸铝陶瓷的制备及性能,论述了钛酸铝陶瓷的稳定性、微裂纹、低热膨胀性,讨论了工艺条件及外加剂对钛酸铝材料性能的影响,最后提出了改善钛酸铝陶瓷性能的技术途径。     

钛酸铝基复合陶瓷的研究

提出了钛酸铝陶瓷研究中存在的问题．论述了颗粒弥散强化陶瓷基复合陶瓷的机理，叙述了第二相颗粒补强钛酸铝基复合陶瓷的国内外研究状况．认为钛酸铝基复合陶瓷是一种很有前途的抗热震冲击且耐高温的材料，并指出了今后的研究方向。     

钛酸铝陶瓷

本文对钛酸铝（Ａｌ２ＴｉＯ５）陶瓷的结构、热分解、热膨胀、机械强度及其影响因素进行了综合阐述，提出抑制热分解，提高其机械强度的方法和途径，并对各种添加物如ＭｇＯ、Ｆｅ２Ｏ３、Ａｌ２Ｏ３、ＺｒＯ２对Ａｌ２ＴｉＯ５性能的影响作了详细论述。     

钛酸铝陶瓷热膨胀机理研究

本文运用了电镜观察、显微结构分析、再加热条件下的热膨胀实验等方法，对钛酸铝陶瓷材料的热膨胀机理进行分析、研究，指出升温时由于微裂纹的弥合导致Ａｌ２ＴｉＯ５陶瓷有较小的热膨胀系数。并着重研究了钛酸铝陶瓷降温时的收缩机理，指出Ａｌ２ＴｉＯ５陶瓷的降温曲线有一最低点，在最低点右边，由于降温收缩造成的内应力还不足以造成大多数晶界和晶粒上发生微裂纹，Ａｌ２ＴｉＯ５陶瓷随着温度的下降而收缩，在最低点左边，由于     

Preparation of porous Al2TiO5-Mullite ceramic by starch consolidation casting and its corrosion resistance characterization

Stabilized Al₂TiO₅ (AT)-mullite (M) porous ceramics were fabricated by starch consolidation casting using corn starch as curing agent and their microstructure, mechanical properties, pore size distribution and corrosion resistance were examined. Results showed that AT-M porous ceramic with the flexural strength of 11.5 MPa, apparent porosity of about 54.7% and pore size distribution in the range of 1–15 µm could be obtained with 10 wt% corn starch addition. Corrosion resistance results showed mass losses in hot H₂SO₄ solution and NaOH solution for 10 h to decreased from 1.03% to 0.36% and 4.39–2% when the calcination temperature increased from 1400 °C to 1450 °C, which proved these AT-M porous ceramics to possess an excellent corrosion resistance in acidic condition when calcined at 1450 °C.     

Nanoindentation of Al2O3/Al2TiO5 composites: Small-scale mechanical properties of Al2TiO5 as reinforcement phase

The mechanical properties of alumina/aluminum titanate composites (Al₂O₃/Al₂TiO₅) were evaluated and analyzed by nanoindentation. Indentations with different penetration depths were performed, and residual imprints on specimens were located and observed by combining complementary characterization techniques. The mechanical response of composites was found to be determined by grain size of alumina and aluminum titanate, as evaluated from indentations performed at 1500 nm of penetration depth. On the other hand, small indents in individual grains permitted to assess the hardness as well as the elastic modulus of non-cracked particles of Al₂TiO₅ through implementation of different analytical indentation models. The attained values for the local mechanical properties were validated through critical comparison of them with those predicted by the rule of mixtures. Results showed no evidence of microcracking on grains of the reinforcing phase for all the tested composites, before and after low penetration depth indentations. Elastic modulus of Al₂TiO₅ was found to be higher than the values reported on bulk aluminum titanate, presumably because of the absence of microcracking for small grain sizes. The bulk composite mechanical response is finally discussed on the basis of contributions from those of the individual phases.     

Microstructural features and mechanical properties of Al2O3-Al2TiO5 composite processed by gel assisted ceramic extrusion

Abstract

The influence of aluminium titanate particulates as second phase reinforcement for alumina matrix composites has been investigated with respect to sintering characteristics, microstructural development, and associated mechanical properties. Composites were fabricated by gel assisted extrusion, using boehmite gel as binder. The aluminium titanate precursor was synthesised by a sol-gel technique and dispersed intimately in the alumina matrix by a colloidal method. A boehmite sol was used as dispersing medium and the extrudable composite paste with high viscosity and yield stress was obtained by controlled gelation followed by filtration. The extruded composite was dried and sintered at a temperature in the range 1350-1550°C. The sintered bodies were characterised in terms of density, room temperature flexural strength, microhardness, and microstructure. Aluminium titanate contents up to 10 wt-% were found to lower the sintering temperature of alumina, from 1550 to 1400°C. The composite sintered at 1400°C attained 97% of theoretical density and showed room temperature flexural strength of 318 MPa and microhardness of 21 GPa. The addition of aluminium titanate resulted in a high density alumina composite at lower sintering temperature with an average grain size of about 2 μm.     

Design and processing of Al2O3–Al2TiO5 layered structures

Al₂O₃–Al₂TiO₅ layered composites were manufactured by a colloidal route from aqueous Al₂O₃ and TiO₂ suspensions with 50 vol.% solids. The mechanical behaviours of individual monolithic composite materials were combined and taken as basis for the design of the layered structures. Residual stresses which are likely to occur due to processing and thermally introduced misfits were calculated and considered for the manufacture of the laminates.Monoliths with 10, 30 and 40 vol.% of second phase showed that increasing proportions of aluminium titanate decrease strength and increase the non-linear behaviour.In order to obtain the desired combination of mechanical behaviours of the layers, two laminate designs with external and central layers of one composition and the alternating internal layer of the other composition were chosen taking into account chemical compatibility and development of residual stresses. In the system AA10, external and central layers of monophase Al₂O₃ with high strength were combined with intermediate layers of Al₂O₃ with 10 vol.% of Al₂TiO₅. The system A10A40 was selected to combine low strength and energy absorbing intermediate layers of Al₂O₃ with 40 vol.% of Al₂TiO₅ and sufficient strength provided by external layers of Al₂O₃ with 10 vol.% of Al₂TiO₅.The stress–strain behaviour of the laminates was linear up to their failure stresses, with apparent strain for zero load after fracture larger than that corresponding to the monoliths of the same composition as that of the external layers. Moreover, the stress drop of the laminate samples occurred in step-like form thus suggesting the occurrence of additional energy consuming processes during fracture.     

Al2O3纤维增强钛酸铝陶瓷

介绍了一种Al2O3纤维增强钛酸铝陶恣复合材料，在一定范围内随着Al2O3纤维含量的增加，复合材料的抗弯强度和断裂韧性均提高，当Al2O3纤维含量达到4.5%(体积分数）时抗弯强度和断裂韧性达到最大值，使钛酸铝基体材料分别提高近120％和75％。     

烧结法制备Al2TiO5材料

以α-Al2O3、钛白粉为主要原料,加入氧化镁、氧化硅、氧化锆稳定剂,采用固相烧结法,于1 500℃/2 h制备了Al2TiO5材料.进行了XRD分析、热膨胀系数测定、循环加热(冷却)5次的综合热分析测试以及激光粒度分析.研究表明,制备材料的主晶相为Al2TiO5,1300℃平均热膨胀系数为3.709 × 10-6/℃,在500～1300℃使用温度区间稳定.经过研磨制备了粒径≤10μm的Al2TiO5粉料.     

钛酸铝基复相材料的研究

研究了引入莫来石和二氧化锆复合相对钛酸铝烧结性能及抗热震性能的影响。借助ＳＥＭ分析了材料的断口形貌,从显微结构上解释了Ａｌ２ＴｉＯ５基复相材料热震后的断裂机制。     

氧化铈改性钛酸铝复相陶瓷热性能的研究

钛酸铝是目前所知唯一集低膨胀和耐高温于一体的结构材料。但它在850℃-1280℃时会分解成Al2O3和TiO2，并且其强度也很低，这两个弱点严重制约了它的使用范围。以CeO2和MgO为添加剂，对钛酸铝陶瓷进行复相改性，用万能材料试验机和扫描电镜等研究了材料的体积密度、热膨胀系数、力学性能和显微结构等。结果表明CeO2可以有效地改善钛酸铝复相陶瓷的各种性质，且5％CeO2-MgO-钛酸铝复相陶瓷经1450℃烧结2小时就可以获得较好的综合性能。     

浅谈我国陶瓷的历史与现状及其发展趋势

陶瓷是泥土与火的艺术,是我国伟大发明之一。     

Al2TiO5添加量对MgO-Al2TiO5复合陶瓷烧结及抗热震性的影响

以纳米MgO粉为原料,选用以纳米Al2O3粉和纳米TiO2粉经1500℃保温3 h烧结制备的Al2TiO5为添加剂,采用固相烧结法经1500℃保温3 h制备了Al2TiO5质量分数分别为0、5%、10%和20%的MgO-Al2TiO5复合陶瓷,并采用XRD、SEM和EDS等研究了Al2TiO5添加量对MgO-Al2TiO5复合陶瓷烧结性能及抗热震性能的影响。结果表明:添加Al2TiO5有利于促进复合陶瓷的烧结,其体积密度和线收缩率随Al2TiO5添加量的增加而增大,当Al2TiO5添加量为20%(w)时,其体积密度和线收缩率分别为3.68 g·cm-3和22.07%;当Al2TiO5添加量为10%(w)时,其抗热震性能最佳。Al2TiO5位于方镁石晶粒交界处,抑制方镁石晶粒生长,阻碍裂纹扩展,使MgO-Al2TiO5复合陶瓷的抗热震性能得到改善。