不同管径CNTs/Al2O3-TiO2复合吸波涂层的拉曼光谱特征及吸波性能研究

摘要

采用超声共混法制备了不同管径的CNTs/Al2O3-TiO2复合粉末,利用等离子喷涂技术制备了CNTs/Al2O3-TiO2复合涂层,对不同管径的CNTs/Al2O3-TiO2复合粉末和喷涂后的复合吸波涂层进行了拉曼光谱分析,等离子喷涂处理后,CNTs的拉曼光谱特征D峰和G峰强度明显增大,随CNTs管径的增大,复合涂层中CNTs的D峰和G峰的强度比ID/IG值减小,石墨化程度提高.吸波反射率结果显示:涂层厚度为1.0 mm的CNTs/Al2O3-TiO2复合涂层的吸波效果不佳,随着厚度的增加,涂层的吸波性能提高.随管径的增大,涂层厚度为1.5 mm的CNTs/Al2O3-TiO2复合涂层的反射率峰值先减小后增大,小于-5 dB频带宽逐渐减小,小于-10 dB频带宽不断增大,谐振频率向高频移动.涂层厚度增加到2.0 mm,CNTs/Al2O3-TiO2复合涂层的反射率峰值向低频移动.%CNTs/AT13 composites were prepared by mixing Al2O3-TiO2 ceramics (AT13) and carbon nanotubes with different diameters in an ultrasonic bath. CNTs/AT13 coatings were prepared by micro-plasma spraying. Raman spectra of CNTs/AT13 composite powders and sprayed coatings with different CNTs diameters were studied. The values of D peak to G peak of the composite coatings increased compared with CNTs/AT13 composite powders. With increasing the diameter of CNTs, the ratio of D peak to G peak of the composite coatings is smaller and the graphitization degree of CNTs was higher. The microwave absorbing properties of the sprayed CNTs/ATI3 coatings with different thicknesses were investigated in the frequency range of 2-18 GHz. when the coating thickness is 1.0 mm, the microwave absorbing ability is poor. With thicker coating, the microwave absorbing ability of the CNTs/AT13 coatings are enhanced. When the coating thickness increases to 1.5 mm, with increasing of the CNTs diameters, the experimental reflectivity peak first decrease and then increase while the resonant frequency moves to the high frequency. The reflection peak of 30-50 nm CNTs/AT13 composite coating is -23.98 dB, and the fre-quency bandwidth for less than -5 dB and -10 dB is 6.40 GHz and 3.36 GHz, respectively. With increasing diameters of CNTs, the frequency bandwidth for less than -5 dB decrease, the frequency bandwidth for less than -10 dB increase. When the coating thickness increases to 2.0 mm, the resonant frequency of the CNTs/AT13 composite coating moves to low frequency.