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为了改善Fe粉的微波吸收性能,采用sol-gel法与H_2还原法制备了w(Al_2O_3)为0.5%~5.0%的Fe/Al_2O_3复合粉。利用SEM和激光粒度分析仪分析了所制粉末的形貌与粒度分布;并将所制复合粉末与石蜡按质量比80:20制成Fe/Al_2O_3/石蜡复合材料,研究w(Al_2O_3)对复合材料微波吸收性能的影响。结果表明:Fe/Al_2O_3复合粉的外形呈片状与针状,其粒度分布很宽。当w(Al_2O_3)由0增加到5.0%时,复合材料的复介电常数实部ε′从11增加至21;复磁导率虚部μ″呈多模共振的曲线形式;w(Al_2O_3)为2.0%,厚为2mm的Fe/Al_2O_3/石蜡复合材料的–5dB反射损失R频宽为4.6GHz。 相似文献
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采用CO2激光器在Q235钢基体表面激光原位合成TiC/Ni复合涂层;借助于扫描电镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)、显微硬度计、ML-100型磨粒磨损试验机对涂层组织结构、物相、组成成分、硬度及耐磨性能进行了分析。结果表明: 在Q235表面激光熔覆(Ni+Ti+C)混合粉末原位制备出了TiC /Ni复合陶瓷涂层, 涂层组织细密、无裂纹、气孔且与基体呈良好的冶金结合, TiC颗粒呈现块状和花瓣状组织;从表层到底部TiC颗粒数量逐渐减少;添加Ti和C的复合涂层较镍基激光熔覆层, 其显微硬度和耐磨性能都得到了一定的提高。 相似文献
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The composition of 98.0(Al1.9Fe0.1O3)/2.0SiO2 was synthesized by modifying auto-combustion method and the effect of calcination temperature on structure and optical properties were studied. The prepared powders were characterized by X-ray diffraction (XRD) patterns, X-ray fluorescence (XRF) spectrometry, Ultraviolet-visible (UV–vis) spectra and Fourier transform infrared (FTIR) spectroscopy. The particle size distribution and the specific surface area of nanoparticles were studied using Transmission electron microscopy (TEM) and BET analysis technique. Adopting Kramers–Kronig relation, FTIR and UV–vis spectra, the optical constants of nano-alumina, including optical band gap (Eg), refractive index (n), extinction coefficients (k), real (ε1) and imaginary parts (ε2) of dielectric function were obtained. The results of optical band gap values indicate quantum confinement effect. The energy loss functions were determined to show loss of energy that transmit through a solid. 相似文献