石墨膨胀玻化微珠砂浆的吸波性能

Microwave Absorbing Properties of Graphite Expanded and Vitrified Small Ball Mortar

关键词:  石墨  石墨膨胀玻化微珠砂浆  反射率  吸波性能  导热系数

Key words:  graphite  graphite expanded and vitrified small ball mortar(GEVSBM)  reflectivity  microwave absorbing property  thermal conductivity

摘要:

采用弓形反射法测试了石墨、膨胀玻化微珠(EVSB)、发泡剂掺量以及材料厚度对石墨膨胀玻化微珠砂浆(GEVSBM)在8～18GHz吸波性能的影响.结果表明：GEVSBM的吸波性能随石墨掺量的增加逐渐增强，石墨的逾渗阈值为水泥质量的10%；增加EVSB或发泡剂掺量可显著增强GEVSBM的吸波性能；石墨和发泡剂掺量分别为水泥质量的10.0%和2.5%时，GEVSBM的反射率降至-20.68dB，小于-10.00dB的有效带宽可达3.0GHz；试件厚度增大，GEVSBM的反射率逐渐降低，但降低幅度逐渐减小.研究表明，GEVSBM具有良好的吸波和保温性能，可同时满足建筑电磁防护和节能的要求.

Abstract:

At 818GHz，the microwave absorbing properties of graphite expanded and vitrified small ball mortars(GEVSBM) were tested by bow reflection method. Factors affecting the microwave absorbing property of GEVSBM, such as graphite content, EVSB use level, foaming agent use level and specimen thickness were studied. The results show that the microwave absorbing properties of GEVSBM are improved gradually with increasing graphite content, and the percolation threshold of graphite in GEVSBM is 10% of cement content. The reflectivity of GEVSBM is improved with the increase of use level of foaming agent or EVSB . The minimum reflectivity of GEVSBM is -20.68 dB when the graphite content and foaming agent use level are 10.0% and 2.5% of cement content, respectively, and the effective bandwidth less than -10.00 dB is 3.0 GHz. The reflectivity of GEVSBM is improved with the increase of material thickness, but the increase value amplitude of reflectivity reduces gradually. GEVSBM exhibits good performance in microwave absorbing and thermal insulation, which can meet the requirements of building electromagnetic radiation protection and building energy saving.