| 化学沉淀-局部规整法制备棒状M型钡铁氧体的形成历程 |
| Formation Process of M-type Ba-ferrite from Precipitation-toptactic Reaction Method |
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| 摘要: 以针状α-FeOOH为原料，采用化学沉淀-局部规整法制备了棒状BaFe12O19，通过TG/DTA、FTIR、XRD及SEM/EDS方法研究了BaFe12O19的形成历程。结果表明，前驱体为晶态BaCO3包覆针状α-FeOOH复合物且呈现较好一维针状形貌，其长径比为16～17；前驱体焙烧过程为α-FeOOH首先脱去-OH生成中间相α-Fe2O3，尔后α-Fe2O3与BaCO3反应生成另一中间相BaFe2O4，最后两中间相α-Fe2O3和BaFe2O4在高温(900 ℃以上)条件下反应生成目标产物BaFe12O19。固相反应引起的晶相转变过程中前驱体焙烧物的长径比随焙烧温度的增加逐渐减小，1 000℃焙烧产物长径比为7～8，存在极少量BaFe2O4和α-Fe2O3中间相，1 100 ℃焙烧产物长径比为2.5～7.0，为BaFe12O19纯相。 |
| 关键词: 钡铁氧体 化学沉淀-局部归整法 历程 制备 |
| 基金项目: |
| Abstract: Using α-FeOOH needle particles as raw material, M-type Ba-ferrite was synthesized by precipitation-toptactic reaction method. The formation process of BaFe12O19 was studied by using TG/DTA, FT-IR, XRD and SEM/EDS. The BaFe12O19 precursor is a compound of pod-like α-FeOOH coated with crystalline BaCO3, showing a length-diameter ratio of 16～17. During the calcination process of the precursor, the dehydroxylation of α-FeOOH results in the formation of α-Fe2O3 mesophase, and then α-Fe2O3 reacts with BaCO3 to form another BaFe2O4 mesophase. Finally, the two mesophases of α-Fe2O3 and BaFe2O4 form the final product of BaFe12O19. The length-diameter ratio of calcined particles, therefore, decreases with the increasing of calcination temperature due to the transformation of crystal phases resulted from solid state reaction above. The calcined product at 1 000 ℃ is the final product of BaFe12O19 with a length-diameter ratio of 7～8, containing a small quantity of α-Fe2O3 and BaFe2O4 mesophase, and at 1 100 ℃ is pure BaFe12O19 phase with a length-diameter ratio of 2.5～7.0. |
| Keywords: Ba-ferrite precipitation-toptactic reaction formed processes preparation |
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| 谭玉琢,孟锦宏,孙 杰,曹晓晖.化学沉淀-局部规整法制备棒状M型钡铁氧体的形成历程[J].无机化学学报,2008,24(12):1989-1993. |
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