On the sol-gel synthesis and characterization of strontium ferrite ceramic material

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• 作者：Shivendra Kumar Jaiswal ; Vijay Kumar Kashyap ; Jitendra Kumar ; ^{jk@iitk.ac.in}
• 关键词：Ceramics ; Sol&ndash ; gel chemistry ; Mö ; ssbauer spectroscopy ; X-ray diffraction ; Thermogravimetric analysis (TGA)
• 刊名：Materials Research Bulletin
• 出版年：2012
• 期刊代码：60_00255408
• 类别：ms
• 出版时间：March, 2012
• 卷：47
• 期：3
• 页码：692-699
• 文件大小：1556 K

摘要

A simple oxalate based sol-gel process has been described to produce a highly stable anion deficient strontium ferrite for separation of oxygen from air. The method involves metal nitrates and oxalic acid precursors with ethanol and water as solvents, gel formation, digestion for 4 h, drying at 150 掳C for 24 h, and finally decomposition at 800 掳C in air. The resulting material (i) exhibits a single perovskite-type cubic (SrFeO_3鈭?em>尉; 尉 鈭?#xA0;0.13) phase with a_o = 3.862 卤 0.002 脜, (ii) contains both the Fe⁴⁺ and Fe³⁺ species in 2.8:1 ratio, (iii) undergoes Fe⁴⁺ 鈫?#xA0;Fe³⁺ reduction upon heating at 650 掳C in rare gas ambient and transition to an orthorhombic phase with a 鈭?#xA0;a_o鈭?, b 鈭?#xA0;4a_o, c 鈭?#xA0;a_o鈭?, which reverts back to cubic phase with oxygen uptake at elevated temperatures, and (iv) acts as filter for air with excellent oxygen permeation, typical flux density value being 2.45 ml/cm² min at 1000 掳C.