Ba_(0.8)La_(0.2)Co_2Fe_(16)O_(27)的制备及电磁损耗性能研究

Study on Preparation and Electromagnetic Loss Property of Ba_(0.8)La_(0.2)Co_2Fe_(16)O_(27) Barium-Ferrite

以硝酸钡、硝酸铁、硝酸钴、硝酸镧和柠檬酸为原料,采用溶胶-凝胶法制备前驱体,在1 200℃下煅烧3 h合成了W型钡铁氧体。通过TG/SDTA对前驱体进行分析,发现柠檬酸在240℃附近开始分解,450℃左右存在柠檬酸的二次分解。利用XRD、IR和SEM及TEM等对产品进行了表征,结果表明：Ba0.8La0.2Co2Fe16O27属于六方晶系,结晶完整,Co2＋—O,Fe3＋—O,Ba—O键分别在580,548,430 cm-1左右出现的吸收峰。由SEM和TEM观察表明,样品呈松散多孔状,由较小粒子组成,晶粒大小在100 nm左右。采用矢量网络测试仪对产品在1-20 GHz的频率下进行了电磁损耗性能测试,结果表明：在该频率范围内Ba0.8La0.2Co2Fe16O27具有优良的电磁损耗特性。

A precursor was prepared by sol-gel method with Ba（NO3）2,Fe（NO3）3·9H2O,Co（NO3）2·6H2O,La（NO3）3·6H2O and C6H8O7·H2O as raw material.W-type barium-ferrite was synthesized by calcining the precursor for 3 hrs at 1 200 ℃.The TG/SDTA analysis of the precursor showed that C6H8O7·H2O decomposed at 240 ℃ for the first time and at about 450 ℃ for the second time.The product was characterized and analyzed by XRD,IR,SEM and TEM.The results indicated that the product belongs to single phase hexagonal crystal system,with complete crystallization.The absorption peaks of Co2＋—O,Fe3＋—O and Ba—O bands emerged at 580,548,430 cm-1 in the IR pattern.It is known from SEM and TEM observation that the sample was loose and porous and was composed of small particles with grain size of about 100 nm.Electromagnetic loss property of the sample was tested by vector network analyzer at 1～20 GHz.The results indicated that Ba0.8La0.2Co2Fe16O27 had excellent magnetic loss property at the range of frequencies.