Effect of La2O3 additives on the strength and microstructure of mullite ceramics obtained from coal gangue and γ-Al2O3
Effect of La2O3 additives on the strength and microstructure of mullite ceramics obtained from coal gangue and γ-Al2O3
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DOI：
10.1016/j.ceramint.2013.02.016
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发表时间：
2013-08-01
影响因子：
5.2
通讯作者：
Huang, Juntong
中科院分区：
文献类型：
--
作者：
Ji, Haipeng;Fang, Minghao;Huang, Juntong
以煤矸石和γ-Al_2O_3为原料，在1400-1550 ℃保温4 h的条件下，通过添加La_2O_3增强各向异性生长，制备了具有互锁柱状晶的自强化莫来石陶瓷。研究了La 2 O3对复合材料抗弯强度、显微组织演变和相组成的影响。结果表明，La 2 O3的加入显著提高了陶瓷的抗弯强度。对于在1550 ℃下烧结的样品，随着La 2 O3含量从0摩尔%增加到10摩尔%，弯曲强度从64 MPa增加到218 MPa。X射线衍射分析表明，二次莫来石的形成温度降低了约50 ℃，通过添加La 2 O3。扫描电子显微镜照片显示，添加La 2 O3的莫来石主要以长柱状形式存在，纵横比为3-6，形成互锁网络结构。联锁莫来石柱，连同增强的致密化行为，有助于提高抗弯强度。(C)2013 Elsevier Ltd和Techna Group S.r.l. All rights reserved.
Self-strengthened mullite ceramics with interlocking columnar grains formed through enhanced anisotropic growth by adding La2O3 were prepared from coal gangue and gamma-Al2O3 within the temperature range 1400-1550 degrees C and holding time of 4 h. The effects of La2O3 on the bending strength, microstructural evolution, and phase composition were studied. The results showed that the bending strength of the as-prepared ceramics was significantly improved by the addition of La2O3. For samples sintered at 1550 degrees C, the bending strength increased from 64 MPa to 218 MPa as the La2O3 content increased from 0 mol% to 10 mol%. X-ray diffraction analysis suggested that the formation temperature of secondary mullite was lowered by about 50 degrees C by adding La2O3. Scanning electron micrographs revealed that the La2O3-added mullite mostly existed in long, columnar form, with aspect ratios of 3-6, forming an interlocking network structure. The interlocking mullite columns, together with the enhanced densification behaviour, contributed to the improved bending strength. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.