热喷涂纳米β-SiC/LBS涂层的吸波性能

Absorber performance of thermally sprayed nanometer β-SiC/LBS matrix microwave absorber coatings

应用喷雾造粒技术对纳米β-SiC/LBS复合吸波粉末进行团聚造粒,采用超音速火焰喷涂工艺制备高温纳米复合吸波涂层,并对复合涂层性能进行研究。结果表明,颗粒状β-SiC弥散在半熔融状态的LBS中形成涂层。涂层与基体的结合强度为8.46MPa,拉伸过程中,涂层从内部撕裂,并表现为脆性断裂。与普通陶瓷吸波涂层相比,复合涂层的吸波性能得到扩展;随着涂层厚度的增加,复合涂层对电磁波的衰减能力将从高频向低频移动。受到涂层抗拉强度的限制,复合涂层的厚度应该小于1mm。纳米β-SiC含量(质量分数)为46%时,复合涂层的电磁波反射率系数达到-13dB;当在涂层厚度相同而微波频率大于14GHz时,复合涂层的电磁波反射率系数均小于-10dB。数值模拟结果表明,当β-SiC质量含量为46%时,复合涂层的吸波性能最佳。

The nanometer agglomerate β-SiC/Li2O-B2O3-SiO2 powders were prepared by spraying granulation.The composite absorber coatings were fabricated by high temperature velocity oxygen fuel（HVOF） thermal spraying technique,and the performances of the coatings were studied.The results show that the microstructure of the coatings is constructed with the SiC particles dispersing in the melting LBS phases.The tensile strength of the coatings is 8.46 MPa,and the crack occurs in the coatings and takes on the brittle rupture in the course of the tensile stress.The microwave reflectivity of the coatings is expanded,compared with that of normal absorber ceramic coatings.When the thickness of the coatings increases,the microwave reflectivity shifts from high frequency to low frequency.However,the thickness of the coatings should be less than 1 mm restricting with the tensile strength of the coatings.When the mass fraction of β-SiC is 46%,the microwave reflectivity coefficient of the coatings can arrive to-13 dB.Especially,at the same thickness of the coatings,when the microwave frequency is larger than 14 GHz,the reflectivity coefficients are all less than-10 dB.The simulated result shows that the microwave absorbing performance of the coatings is the best when the mass fraction of β-SiC is 46%.