W型Ba_(0．8)La_(0．2)Co_2Fe_(16)O_(27)微波吸收材料的制备与表征

Prepared and characteristics of the microwave absorption materials of W-type Ba_(0.8)La_(0.2)Co_2Fe_(16)O_(27)

采用柠檬酸溶胶凝胶法制备了稀土W型六角铁氧体Ba_(0.8)La_(0.2)Co_2Fe_(16)O_(27)粉晶,用DSC-TGA、FT-IR、XRD、SEM分析了样品的形成过程、微观形貌、粒径和晶体结构,根据微波矢量网络分析仪测试的样品在2～18GHz微波频率范围的电磁参数计算了电磁损耗角正切及微波反射率。研究结果表明,煅烧2h能得到单一的W型相Ba_(0.8)La_(0.2)Co_2Fe_(16)O_(27);晶粒为六角块状结构,大小均为200nm左右;Ba_(0.8)La_(0.2)Co_2Fe_(16) O_(27)样品厚度为1.9mm时,12GHz位置处吸收峰为16.2dB,10dB频宽为4.0GHz;微波吸收主要由磁损耗引起。

W-type rare-earth hexaferrite Ba0.8 La0.2 Co2 Fe16 O27 was prepared by citric acid sol-gel method. Differential scanning calorimetry and thermogravimetry analysis （DSC-TGA）, fourier transform infrared transmission （FT-IR） spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM） were employed to analyze the formation process ,structure, surface morphology of samples. The electromagnetic parameters were measured in the frequency range of 2-18GHz by microwave vector network analyzer. The electromagnetic loss tangent and the microwave reflectivity were calculated from the measured data. The results show that Ba0.8La0.2 Co2Fe16O27 after calcinations at 1200℃ for 2h is single W phase. The particle size of sample is about 200nm and the morphology is hexagonal. When the thickness of the sample is 1.90mm, the highest absorption peak is reaches 16.2dB in 12GHz and the effective band width of more than 10dB reaches 4.0GHz. The microwave absorption majorly results from magnetic loss.