东北大学学报(自然科学版) ›› 2024, Vol. 45 ›› Issue (2): 193-200.DOI: 10.12068/j.issn.1005-3026.2024.02.006

• 材料与冶金 • 上一篇    

铁酸钙与TiO2的扩散反应特征

曹晓舟, 邵胜琦, 岳宏瑞   

  1. 东北大学 冶金学院,辽宁 沈阳 110819
  • 收稿日期:2022-10-18 出版日期:2024-02-15 发布日期:2024-05-14
  • 作者简介:曹晓舟(1979-),男,山东单县人,东北大学副教授.
  • 基金资助:
    国家自然科学基金青年基金资助项目(52104296);中国博士后科学基金资助项目(2022M710640)

Diffusion Reaction Characteristics of Calcium Ferrite and TiO2

Xiao-zhou CAO, Sheng-qi SHAO, Hong-rui YUE   

  1. School of Metallurgy,Northeastern University,Shenyang 110819,China. Corresponding author: YUE Hong-rui,E-mail: yuehongrui@mail. neu. edu. cn
  • Received:2022-10-18 Online:2024-02-15 Published:2024-05-14

摘要:

钒钛磁铁矿烧结过程中,TiO2会与Fe2O3竞争CaO,抑制铁酸钙(C x F)的形成,进而影响烧结矿品质.通过制备C x F/TiO2扩散偶的方法,直观地研究CaO-Fe2O3-TiO2体系的扩散反应.运用电子探针和X射线衍射分析仪等手段对反应界面不同位置处的生成物进行分析和表征,研究了在扩散温度为900~1 050 ℃,时间为1~4 h的条件下C x F与TiO2界面的反应特征;分析了温度及时间对生成相的种类、分布及形貌特征的影响.结果表明,从C x F一侧到TiO2一侧,主要的物相有C x F,CF,Fe2O3,CaTiO3,TiO2,其中钙钛矿(CaTiO3)是主要的生成产物.随温度从900 ℃升高至1 050 ℃,CaTiO3的厚度从8.1 μm增大至90.2 μm;随时间从1 h延长至4 h,CaTiO3的厚度从47.4 μm增大至121.4 μm.同时,CaTiO3的扩散厚度与扩散时间的平方根呈良好的线性关系,这表明CaTiO3的生成受扩散过程控制.进一步地,使用空位扩散机理解释了CaTiO3在CaO-Fe2O3-TiO2体系的生成过程.

关键词: 铁酸钙, TiO2, 扩散偶, 扩散厚度, 空位扩散机理

Abstract:

During sintering the vanadium titanomagnetite, TiO2 competes with Fe2O3 for CaO, which inhibits the formation of calcium ferrite (C x F) and affects the sinter quality. In this paper, the diffusion reaction of CaO-Fe2O3-TiO2 system is intuitively studied by preparing C x F/TiO2 diffusion couple. Electron probe and X-ray diffractometer are used to analyze and characterize the products at different positions of the reaction interface. The reaction characteristics of C x F/TiO2 interface are studied at the diffusion temperature of 900~1050 ℃ and the time of 1~4 h. The effects of temperature and time on the types, distribution and morphology of the generated phases are discussed. The results show that the main phases are C x F, CaO·Fe2O3(CF), Fe2O3, CaTiO3 and TiO2 from the C x F- to TiO2-layer, among which perovskite (CaTiO3) is the main product. The thickness of CaTiO3 increases from 8.1 μm to 90.2 μm with the temperature increasing from 900 ℃ to 1 050 ℃; it increases from 47.4 μm to 121.4 μm with the time increasing from 1 h to 4 h. Meanwhile, the diffusion thickness of CaTiO3 has a good linear relationship with the square root of diffusion time, which indicates that the formation of CaTiO3 is controlled by diffusion process. Furthermore, the formation process of CaTiO3 in CaO-Fe2O3-TiO2 system is explained by vacancy-mediated diffusion mechanism.

Key words: calcium ferrite, TiO2, diffusion couple, diffusion thickness, vacancy-mediated diffusion mechanism

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