摘要
以尿素、硼酸和热解炭（PyC）粉为原料,利用化学转化法,在1750℃、N2气氛下反应6 h,制备了PyC/BN复合粉。采用XRD、XPS、SEM、DTA/TGA对PyC/BN复合粉的物相组成、化学成分、表面形貌及抗氧化性能进行了表征,并用矢量网络分析仪测试了PyC/BN复合粉在2-18 GHz频段内的吸波性能。结果表明：生成的h-BN颗粒在PyC粉表面形成包裹层,其尺寸为几十至几百纳米。相比于PyC粉,PyC/BN复合粉的抗氧化性能明显提高,在1200℃时其质量仍剩余50%以上,而PyC粉在940℃时已被氧化完全。同时,由于波阻抗增大,电子位移极化、界面极化、多重散射和λ/4干涉相消作用,使得PyC/BN复合粉在相同厚度下（d=2 mm）,其反射率峰值达到–27.2 dB,反射率小于–10 dB的频宽为2.6 GHz;且随着厚度的增加,其反射率峰值均小于–10 dB,并出现多重吸收峰。PyC/BN复合粉可作为理想的轻质、耐高温、强吸收的吸波剂应用于微波领域。
PyC/BN composite powders were synthesized via chemical reaction of boric acid, urea and PyC powders at 1750℃ for 6 h in nitrogen. The phases, chemical compositions, surface morphologies and oxidation resistance of PyC/BN composite powders were characterized by XRD, XPS, SEM and DTA/TGA instruments, respectively. The microwave absorption properties of PyC/BN composite powders were measured by using a microwave network analyzer in the frequency range of 2-18 GHz. The results show that generated h-BN particles are coated on the surfaces of PyC powders with the dimension from tens of nanometers to hundreds of nanometers. Compared with PyC powders, the oxidation resistance of PyC/BN composite powders is improved. The mass of PyC/BN composite powders remains over 50% at 1200~C whereas PyC powders are oxidized completely at 940℃. Due to higher microwave impedance, electronic displacement polarization, interface polarization, multiple scattering and L/4 destructive interference effect, the reflectivity peak of PyC/BN composite powders reaches -27.2 dB and the bandwidth of the reflectivity below -10 dB is 2.6 GHz under the same thickness （2 mm）. And the reflectivity peaks are all less than -I0 dB and multiple absorbing peaks appear with the increase of thickness. PyC/BN composite powders are supposed to be ideal microwave absorbers with lighter weight, high temperature resistance and strong microwave absorption.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第5期479-484,共6页
Journal of Inorganic Materials
基金
国家重点基础研究发展规划(973计划)(2011CB605804)
湖南省研究生科研创新项目(CX2011B114)
中南大学研究生学位论文创新基金(1960-71131110011)~~
关键词
PyC
BN复合粉
氮化硼
抗氧化性能
吸波性能
PyC/BN composite powders
boron nitride
oxidation resistance
microwave absorption properties
