多晶二氧化铈在真空和空气中加热时的结构和相变缺陷

A. E. Solovyeva
{"title":"多晶二氧化铈在真空和空气中加热时的结构和相变缺陷","authors":"A. E. Solovyeva","doi":"10.17073/1683-4518-2023-7-42-51","DOIUrl":null,"url":null,"abstract":"Structural changes in cerium dioxide, when heated in vacuum in the range of 25‒1600 °C, in air in the range of 25‒1500 °C, and during successive annealing in the range of 1600‒2100 °C in air, followed by quenching in water, were studied. In the crystal lattice of CeO2‒х, the F → F1 phase transformation in vacuum proceeds in the range of 1100‒1600 °C; additionally, at 1200 °C, X-ray lines of the C-type Ce2O3 phase appear. The thermal expansion coefficient of phases of the fluorite type F and F1 in the range of 25‒1500 °C in air, as well as phases of the fluorite type F, F1 and type C Ce2O3 in the range of 25‒1600 °C are determined in vacuum and their dependence on the change in the oxygen content in the CeO2‒х crystal lattice was found. The kinetic conditions for reduction of cerium dioxide in vacuum and oxidation in air are different. The cubic structure of the fluorite type F CeO2‒х, when the samples are heated in air, is preserved up to 1800 °C with the content of anionic vacancies, at 1900 °C the transformation F → F1 occurs. The formation of loops, edge and screw dislocations in the structure of cerium dioxide grains after annealing of samples in the range of 1900‒2100 °C in air were discovered for the first time. The decomposition of the structure F1 into cerium oxide phases of types F and C proceeds at 2100 °C along the height and boundaries of screw dislocations. It was found that fragments of the C-type phase of cerium oxide are located on loops along the height of screw dislocations, which indicates the movement and evaporation of these fragments. When the samples are oxidized at 1600 °C in air, the black-colored C Ce2O3‒х phase in a gradient of different concentrations moves along certain trajectories to opposite ones. grain boundaries, abuts against dislocation loops, bends them, and oxidizes to phases F1 and F. In the structure of polycrystalline cerium dioxide, when heated in vacuum and in air, certain concentrations of defects control phase transformations.","PeriodicalId":19463,"journal":{"name":"NOVYE OGNEUPORY (NEW REFRACTORIES)","volume":"100 ","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The defects of structural and phase transformations in polycrystalline cerium dioxide under heating in vacuum and in air\",\"authors\":\"A. E. Solovyeva\",\"doi\":\"10.17073/1683-4518-2023-7-42-51\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Structural changes in cerium dioxide, when heated in vacuum in the range of 25‒1600 °C, in air in the range of 25‒1500 °C, and during successive annealing in the range of 1600‒2100 °C in air, followed by quenching in water, were studied. In the crystal lattice of CeO2‒х, the F → F1 phase transformation in vacuum proceeds in the range of 1100‒1600 °C; additionally, at 1200 °C, X-ray lines of the C-type Ce2O3 phase appear. The thermal expansion coefficient of phases of the fluorite type F and F1 in the range of 25‒1500 °C in air, as well as phases of the fluorite type F, F1 and type C Ce2O3 in the range of 25‒1600 °C are determined in vacuum and their dependence on the change in the oxygen content in the CeO2‒х crystal lattice was found. The kinetic conditions for reduction of cerium dioxide in vacuum and oxidation in air are different. The cubic structure of the fluorite type F CeO2‒х, when the samples are heated in air, is preserved up to 1800 °C with the content of anionic vacancies, at 1900 °C the transformation F → F1 occurs. The formation of loops, edge and screw dislocations in the structure of cerium dioxide grains after annealing of samples in the range of 1900‒2100 °C in air were discovered for the first time. The decomposition of the structure F1 into cerium oxide phases of types F and C proceeds at 2100 °C along the height and boundaries of screw dislocations. It was found that fragments of the C-type phase of cerium oxide are located on loops along the height of screw dislocations, which indicates the movement and evaporation of these fragments. When the samples are oxidized at 1600 °C in air, the black-colored C Ce2O3‒х phase in a gradient of different concentrations moves along certain trajectories to opposite ones. grain boundaries, abuts against dislocation loops, bends them, and oxidizes to phases F1 and F. In the structure of polycrystalline cerium dioxide, when heated in vacuum and in air, certain concentrations of defects control phase transformations.\",\"PeriodicalId\":19463,\"journal\":{\"name\":\"NOVYE OGNEUPORY (NEW REFRACTORIES)\",\"volume\":\"100 \",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2023-11-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"NOVYE OGNEUPORY (NEW REFRACTORIES)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.17073/1683-4518-2023-7-42-51\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"NOVYE OGNEUPORY (NEW REFRACTORIES)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.17073/1683-4518-2023-7-42-51","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0

摘要

在 CeO2-х 的晶格中,真空中的 F → F1 相变在 1100-1600 ℃ 范围内进行;此外,在 1200 ℃ 时,出现了 C 型 Ce2O3 相的 X 射线。测定了 25-1500 ℃ 空气中 F 型和 F1 型萤石相的热膨胀系数,以及 25-1600 ℃ 真空中 F 型、F1 型和 C 型 Ce2O3 相的热膨胀系数,并发现了它们与 CeO2-х 晶格中氧含量变化的关系。二氧化铈在真空中还原和在空气中氧化的动力学条件是不同的。当样品在空气中加热时,F 型 CeO2-х 萤石的立方结构在 1800 ℃ 时仍保持不变,并含有阴离子空位,在 1900 ℃ 时发生 F → F1 的转变。在 1900-2100 °C的空气中退火后,二氧化铈晶粒结构中形成了环状、边缘和螺旋位错,这是首次发现。在 2100 ℃ 时,结构 F1 沿着螺旋位错的高度和边界分解成 F 型和 C 型氧化铈相。研究发现,C 型氧化铈相的碎片位于沿螺旋位错高度的环上,这表明了这些碎片的移动和蒸发。当样品在 1600 °C 的空气中氧化时,不同浓度梯度的黑色 C Ce2O3-х 相沿着一定的轨迹向相反的轨迹移动,与位错环相邻,使位错环弯曲,并氧化成 F1 和 F 相。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
The defects of structural and phase transformations in polycrystalline cerium dioxide under heating in vacuum and in air
Structural changes in cerium dioxide, when heated in vacuum in the range of 25‒1600 °C, in air in the range of 25‒1500 °C, and during successive annealing in the range of 1600‒2100 °C in air, followed by quenching in water, were studied. In the crystal lattice of CeO2‒х, the F → F1 phase transformation in vacuum proceeds in the range of 1100‒1600 °C; additionally, at 1200 °C, X-ray lines of the C-type Ce2O3 phase appear. The thermal expansion coefficient of phases of the fluorite type F and F1 in the range of 25‒1500 °C in air, as well as phases of the fluorite type F, F1 and type C Ce2O3 in the range of 25‒1600 °C are determined in vacuum and their dependence on the change in the oxygen content in the CeO2‒х crystal lattice was found. The kinetic conditions for reduction of cerium dioxide in vacuum and oxidation in air are different. The cubic structure of the fluorite type F CeO2‒х, when the samples are heated in air, is preserved up to 1800 °C with the content of anionic vacancies, at 1900 °C the transformation F → F1 occurs. The formation of loops, edge and screw dislocations in the structure of cerium dioxide grains after annealing of samples in the range of 1900‒2100 °C in air were discovered for the first time. The decomposition of the structure F1 into cerium oxide phases of types F and C proceeds at 2100 °C along the height and boundaries of screw dislocations. It was found that fragments of the C-type phase of cerium oxide are located on loops along the height of screw dislocations, which indicates the movement and evaporation of these fragments. When the samples are oxidized at 1600 °C in air, the black-colored C Ce2O3‒х phase in a gradient of different concentrations moves along certain trajectories to opposite ones. grain boundaries, abuts against dislocation loops, bends them, and oxidizes to phases F1 and F. In the structure of polycrystalline cerium dioxide, when heated in vacuum and in air, certain concentrations of defects control phase transformations.
求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
自引率
0.00%
发文量
0
期刊最新文献
Study of the effect of high-temperature annealing on the structure and properties of a composite material based on TiC/TiB2/Ti3SiC2 Formation of the structure of a ceramic composite of the Al2 O3 ‒ZrO2 system during the synthesis of strontium hexaaluminate during firing Experience and prospects of expanding the use of dry mixes in the manufacture of heat-resistant concretes Acid-resistant material was obtained on the basis of metallurgy waste without the use of traditional natural materials The influence of the glass phase of fused refractories on their operational and technological properties
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1