PDF《氧分压对铁铝尖晶石稳定性的影响》

第44 卷第

6 期201

6 年6月硅酸盐学报Vol.

44,No.

6 June,2016 JOURNAL OF THE CHINESE CERAMIC SOCIETY http://www.gxyb.cbpt.cnki.net DOI:10.14062/j.issn.0454-5648.2016.06.22 氧分压对铁铝尖晶石稳定性的影响 李志坚,付雪冰,丁达飞,栾旭,吴锋(辽宁科技大学高温材料与镁资源工程学院,辽宁 鞍山 114051) 摘要:将烧结铁铝尖晶石制成 1.0~0.088 mm 样品,控制气氛中氧气体积分数,进行 25~1

400 ℃的热重分析,研究不同含 氧分压下铁铝尖晶石的氧化行为,并对氧化前后样品进行 X 射线衍射、扫描电子显微镜及能谱分析.结果表明:烧结铁铝尖 晶石的氧化为保护型氧化,气氛中氧气体积分数在 0.3%左右时,铁铝尖晶石较为稳定,晶粒表面氧化形成排列规整致密的刚 玉及赤铁矿致密保护层,内部未氧化;

氧气体积分数在 8.0%左右时,铁铝尖晶石完全氧化,产生片状、粒状的刚玉相及赤铁 矿相;

氧气体积分数在 18.0%左右时,样品中残留较多纯净铁铝尖晶石相,铁铝尖晶石晶粒表面氧化形成无定形刚玉及赤铁 矿相,氧化程度较为剧烈,晶粒保留八面体结构. 关键词:铁铝尖晶石;

热重分析;

氧含量;

稳定性 中图分类号:TQ175 文献标志码:A 文章编号:0454C5648(2016)06C0916C05 网络出版时间: 网络出版地址: Effect of O2 Partial Pressure on Hercynite Stability LI Zhijian, FU Xuebing, DING Dafei, LUAN Xu, WU Feng (School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051, Liaoning, China) Abstract: A sintered hercynite powder with the sizes of 1.0C0.088 mm was prepared via grinding. The oxidation behavior of the sintered hercynite powder at different oxygen volume fractions was investigated through the thermogravimetric analysis at 25C

1 400 ℃. The fired samples were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry, respectively. The results show that the oxidation of sintered hercynite is protective oxidation. When the oxygen volume fraction is 0.3%, hercynite is more relatively stable and there are some dense and regular arrangement phases of corundum and hematite on the grain surface as a protective layer, and the inside of the grains is not oxidized. When the oxygen volume fraction is 8.0%, hercynite is completely oxidized to form flaky and grainy phases of corundum and hematite. When the oxygen volume fraction is 18.0%, there are some residual pure hercynite phases existed in the specimen, the surface of hercynite grains is oxidized to form some shapelessness phases of corundum and hematite. The oxidization is more serious and the grains are still in an octahedral structure. Keywords: hercynite;

thermogravimetric analysis;

oxygen content;

stability 铁铝尖晶石是目前制备水泥回转窑烧成带用镁 铁铝材料的重要原料,也是推动水泥窑用耐火材料 无铬化的关键材料[1] . 铁铝尖晶石(FeAl2O4, 化学式 为AB2O4)属于 2C3 氧化物尖晶石.在FeAl2O4 晶体 结构中,氧离子作立方最紧密堆积,阳离子(Fe2+ 、 Al3+ )占据由氧离子紧密堆积形成的四面体空位和八 面体空位[2C4] . 在理想条件下, Fe2+ 占据四面体位置, Al3+ 占据八面体位置.然而,在高温条件下,铁铝 尖晶石中的阳离子(Fe2+ 、Al3+ )分布呈现无序性,使得Fe2+ 、Al3+ 均可分布于四面体位置和八面体位 置[2] . Fe2+ 在晶体结构中的占位分布与铁铝尖晶石在 使用过程中 Fe2+ 的扩散及氧化有直接关系, 铁铝尖 晶石在高温环境中氧化实质是 Fe2+ 向Fe3+ 的转化 过程. 收稿日期:2016C01C20. 修订日期:2016C02C06. 基金项目:国家科技支撑计划(2013BAF09B01)资助. 第一作者:李志坚(1958―),男,教授. Received date: 2016C01C20. Revised date: 2016C02C06. First author: LI Zhijian(1958C), male, Professor. E-mail: askj5212086@163.com 第44 卷第