核-壳结构Al_(2)O_(3)@CIPs的制备及其抗氧化性能和吸波性能EI北大核心CSCD

采用球磨-原位氧化法制备出具有核-壳结构的Al_(2)O_(3)@CIPs复合材料。通过X射线衍射仪、热重分析仪、扫描电镜对Al_(2)O_(3)@CIPs的物相组成、质量变化和微观形貌进行分析,研究不同氧化温度对Al_(2)O_(3)@CIPs复合材料电磁性能和吸波性能的影响。结果表明:随着氧化温度的升高,Al_(2)O_(3)@CIPs的壳层出现不同程度的损坏,并伴有Fe氧化物的生成。其中,介电常数先增大后减小,而磁导率则降低。对比CIPs,经过400℃原位氧化获得的Al_(2)O_(3)@CIPs具有良好的吸波性能,对应的介电常数实部约为15,虚部为2.8~4.3。在X波段1.8 mm厚度下可获得3.4 GHz的有效吸收带宽(<-10 dB),而在450℃原位氧化得到的Al_(2)O_(3)@CIPs在11.1 GHz处获得最大的反射损耗,为-30 dB。

Preparation of core-shell Al2O3@CIPs and its anti-oxidation properties and microwave absorbing performance

Core-shell Al₂O₃@carbonyl iron powders (CIPs) were prepared by ball-milling-in-situ oxidation method. The phase composition, mass change and micromorphology of Al₂O₃@CIPs were analyzed by X-ray diffraction, thermogravimetric analyzer and scanning electron microscopy. The effects of various oxidation temperature on electromagnetic properties and absorbing performance of Al₂O₃@CIPs were studied. The results show that, as the oxidation temperature increases, the shell of Al₂O₃@CIPs is damaged to some extent and accompanied by the formation of iron oxides, its permittivity rises first and then declines, while permeability shows a downward trend. Compared with CIPs, Al₂O₃@CIPs obtained by in-situ oxidation at 400℃ achieve excellent electromagnetic wave absorption performance.The real part of the permittivity is about 15, and the imaginary part is 2.8-4.3. The effective absorption band (< -10 dB) of 3.4 GHz can be obtained under the thickness of 1.8 mm in the X-band, while the Al₂O₃@CIPs obtained by in-situ oxidation at 450℃ achieve the maximum reflection loss of -30 dB at 11.1 GHz.