常压烧结制备AlN-W复合微波衰减材料及其性能研究

Study on the Preparation and Properties of AlN-W Microwave Attenuation Materials by Pressureless Sintering

以氮化铝、钨为原料,在氮气气氛下,采用无压烧结方式制备了AlN-W复合微波衰减材料。采用扫描电子显微镜、矢量网络分析仪及激光导热仪对样品的微观结构、介电性能及热导率进行测试分析。结果表明:随着烧结温度的增加,AlN-W复合陶瓷的介电常数逐渐增大,介电损耗变化不大。随着烧结助剂添加量的增加,AlN-W复合陶瓷的介电常数和介电损耗相应增大。随着W含量的增加,AlN-W陶瓷的介电常数呈增加的趋势,介电损耗逐渐降低,当W添加量为60%时损耗几乎为零。随着W颗粒粒径的增加,AlN-W复合陶瓷的介电常数变化不大,介电损耗逐渐降低。由此可通过调节烧结温度、衰减剂含量、衰减剂粒径及烧结助剂的添加量,来制备符合实际需要的复合微波衰减材料。1750℃下制备的A1N-40%W复合陶瓷热导率为91 W/m·K。初步分析了AlN-W复合陶瓷的微波衰减机理。

The aluminum nitride-tungsten composite ceramics could be prepared by pressureless sintering under nitrogen gas with AIN and W particles. The microstructure of composite ceramics was observed by scanning electron microscope. The dielectric property and thermal conductivity of samples were also tested. The experimental results showed that the dielectric constant of the A1N-W composite ceramics gradually increased and dielectric loss little changed with the increase of sintering temperature. Dielectric constant and loss of ceramic composite correspondingly increased with the increase of sintering aid content. The dielectric constant of the ceramic composite showed an increasing trend and the loss decreased gradually with the increase of the W content, the loss is nearly zero when the content of W is 60%. The dielectric constant of the ceramic composite showed a little change and the loss decreased gradually with the increase of the W particle size. Thus by adjusting the sintering temperature,the content and particle size of W and the content of additives to prepare the composite microwave attenuation material which could meet the actual demand. The thermal conductivity of AIN-40% W composite ceramic prepared under 1750 ℃ was 91 W/m · mechanism was preliminary analyzed. K. The composite ceramic microwave attenuation.