磁性能的影響
(1. 江蘇大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212013；
2. 南京航空航天大學(xué) 機(jī)電工程學(xué)院，南京 210016)
摘 要: 以檸檬酸及金屬鹽為原料，采用有機(jī)凝膠先驅(qū)體轉(zhuǎn)化法制備直徑0.5~3.0 μm、平均晶粒尺寸為8.7~31.8 nm的Mn0.6Zn0.4Fe2O4鐵氧體纖維。利用XRD、SEM和VSM分別對(duì)前驅(qū)體凝膠的結(jié)構(gòu)、熱處理產(chǎn)物的物相、形貌及磁性能進(jìn)行表征。結(jié)果表明：Mn-Zn鐵氧體相的穩(wěn)定性主要受熱處理氣氛中氧含量的影響，在空氣氣氛中將發(fā)生部分分解，而在氮?dú)鈿夥罩心塬@得純的尖晶石型鐵氧體相；在400 ℃時(shí)獲得的Mn0.6Zn0.4Fe2O4鐵氧體纖維因晶粒尺寸小于臨界尺寸而表現(xiàn)出超順磁特性，但隨熱處理溫度的升高和保溫時(shí)間的延長(zhǎng)，Mn0.6Zn0.4Fe2O4鐵氧體纖維的飽和磁化強(qiáng)度、矯頑力和晶粒尺寸均逐漸提高，特別是在500 ℃以后，增長(zhǎng)尤為顯著。
關(guān)鍵字: Mn0.6Zn0.4Fe2O4；鐵氧體纖維；有機(jī)凝膠先驅(qū)體轉(zhuǎn)化法；熱處理制度；磁性能
（1. School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. School of Mechanical and Electrical Engineering, Nanjing University of Aeronaustics and Astronaustics,
Nanjing 210016, China）
Abstract:The nanocrystalline Mn0.6Zn0.4Fe2O4 ferrite fibres with diameters between 0.5–3.0 μm and an average crystal size of 8.7–31.8 nm were prepared via organic gel precursor transformation process using metal salts and citric acid as raw materials. The structure and morphologies of the gel precursor and products obtained under different heat-treatment conditions were characterized by XRD and SEM, and the magnetic properties of the fibres were measured by VSM. The results show that the stability of Mn-Zn ferrite phase is mainly affected by the oxygen content in the heat-treated atmosphere. The Mn-Zn ferrite partially decomposes during the heat treatment under ambient atmosphere, while a single spinel-type ferrite phase is obtained in nitrogen atmosphere. Mn0.4Zn0.6Fe2O4 ferrite fibres formed at low heat treatment temperature of 400 ℃ exhibits superparamagnetism due to the grain size below threshold value. With increasing calcinating temperature and prolonging holding time, the saturation magnetization, coercivity and grain size for these fibres increase, and become obviously larger when the temperature is above 500 ℃.
Key words: Mn0.6Zn0.4Fe2O4; ferrite fibres; organic gel precursor transformation method; heat treatment process; magnetic properties
