微弧等离子喷涂碳纳米管/纳米Al2O3-TiO2复合涂层的吸波性能研究

将碳纳米管与纳米Al₂O₃-TiO₂陶瓷粉末超声共混制备了碳纳米管/纳米Al₂O₃-TiO₂复合粉末，测试了复合粉末在2—18GHz波段的电磁参数.研究表明：随着碳纳米管质量分数的增加，碳纳米管/纳米Al₂O₃-TiO₂复合粉末的复介电常数和损耗角不断增大.当碳纳米管质量分数和厚度增加时，复合粉末对电磁波的反射率峰值先增加后减小，而谐振频率不断向低频移动.采用微弧等离子喷涂制备了7wt%碳纳米管/纳米Al₂O₃-TiO₂复合吸波涂层，当厚度为1.5mm时，涂层最小反射率为-24.0dB，当厚度为2.0mm时，涂层小于-10dB的频带宽为3.60GHz，当温度为500℃高温时，1.0mm厚的涂层最小高温反射率为-12.2dB，小于-10dB频带宽为2.0GHz.复合涂层的实际厚度D与理论厚度d呈线关系：d=0.898D+0.515.关键词：等离子喷涂碳纳米管2O₃-TiO₂')" href="#">纳米Al₂O₃-TiO₂吸波性能

Absorption properties of micro-plasma sprayed carbon nanotube-nanostructure Al2O3-TiO2 composite coatings

Carbon nanotube-nanostructure Al₂O₃-TiO₂ composite powders were prepared by mixing carbon nanotubes with nanostructure Al₂O₃-TiO₂ ceramics in an ultrasonic bath. Electromagnetic parameters of the composite material were determined at 2—18GHz. The experimental results show that the complex permititivity and loss tangent of the dielectric increase as the weight content of carbon nanotubes increases. The minimum absorption value increases firstly and then dtcreases and the resonance frequency gradually moves to the low frequency and with increase of the weight content of carbon nanotubes and the thickness of composite coatings. Carbon nanotube 7wt%-nanostructure Al₂O₃-TiO₂ composite coatings were deposited by micro-plasma spraying. The minimum absorption value for 1.5mm thick composite coatings was -26.3dB. The frequency range for absorption value less than -10dB of 2.0mm thick composite coatings was 3.60GHz. When the 1.0mm thick composite coating was heated to 500℃, the minimum high temperature absorption value was -12.2dB and the frequency range for absorption value less than -10dB was 2.00GHz. There is a linear relationship between experimental and theoretical thickness of composite coatings:d=0.898D+0.515, where D is the experimental thickness and d is the theoretical thickness.