摘要
利用溶胶凝胶自燃烧法 ,在室温下直接合成了 30nm左右的Mn0 .6 Cu0 .2 Zn0 .2 O(Fe2 O3) 0 .98纳米晶铁氧体。借助于DTA -TG ,IR ,XRD和VSM技术 ,对干凝胶的热分解过程 ,自燃烧本质及合成纳米晶的磁性能进行了研究。研究表明 ,由金属的硝酸盐和柠檬酸形成的干凝胶具有自燃烧的特性。自燃烧的实质是在热诱导下的氧化还原反应。XRD结果表明 ,通过自燃烧反应可以直接获得纯的锰铜锌铁氧体相而无Fe2 O3相的存在。当对自燃烧粉进行预烧时 ,随着预烧温度的提高 ,有Fe2 O3相的出现。随着预烧温度的升高 ,Mn0 .6 Cu0 .2 Zn0 .2 O·(Fe2 O3) 0 .98铁氧体粉体的矫顽力由未经预烧时的 9.0 395kA·m- 1 线性下降到经 10 0 0℃预烧后的 4.72 46kA·m- 1 。但是 ,饱和磁化强度的变化却是先下降再升高。所获得的Mn0 .6 Cu0 .2 Zn0 .2 O(Fe2 O3) 0 .
Mn 0.6 Cu 0.2 Zn 0.2 O (Fe 2O 3) 0.98 (MnCuZn) ferrite powders with particle size about 30 nm were directly synthesized by sol-gel auto_combustion method at room temperature. The thermal decomposition, nature of auto_combustion and magnetic properties of the obtained powders were investigated by DTA-TG, IR, XRD and VSM techniques. The results revealed that xerogel derived from the nitrate-citrate exhibit auto_combustion behavior once ignited in air at room temperature. The nature of auto_combustion is considered to be an oxidation_reduction process induced by heat. The results of XRD indicates that pure nanocrystalline Mn 0.6 Cu 0.2 Zn 0.2 O(Fe 2O 3) 0.98 ferrite can be directly obtained after auto_combustion without further calcination and no phase of Fe 2O 3 is detected. The phase of Fe 2O 3 would appear when the auto_combustion powders were calcined at increasing temperature. The coercive force of MnCuZn ferrite powders is linearly decreased from 9.039 5 kA·m -1 (for auto_combustion powders) to 4.724 6 kA·m -1 (for auto_combustion powders calcined at 1 000 ℃ for 2 h) while the calcined temperature increases. However, the values of saturation magnetization firstly decrease, then increase with an increase in calcined temperature. The coercive force and saturation magnetization, of obtained nanosize MnCuZn ferrite powders are high as compared to reported bulk values.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2003年第2期138-142,共5页
Journal of The Chinese Ceramic Society
基金
国家高技术研究发展计划资助项目 (2 0 0 0 1AA32 0 5 0 2 )
