高性能水泥基复合吸波材料的研究
发布时间：2018-10-26 10:32
【摘要】：随着数字通信系统的发展和各种电子设备的广泛应用,电磁辐射污染已经成为一种新的社会公害。针对目前日益恶化的电磁环境以及军事隐身及防护的需求,研究宽频、高效、满足结构承载要求的水泥基复合吸波材料具有十分重要的意义。论文针对目前水泥基复合吸波材料存在吸收效能低、质量大、成本高、稳定性差、承载力低等问题,从阻抗匹配,吸波效能和结构承载等方面进行综合设计,首先探讨了纳米CoFe2O4吸波剂的制备方法,然后分别探讨了掺合料、多孔集料、吸波剂、纤维等组分的品种以及掺量对高性能水泥复合吸波材料的强度、电阻率以及吸波性能的影响。试验结果表明,将原料硝酸钴、硝酸铁和氢氧化钠和分散剂聚乙烯醇按1:2:8.1:0.25的化学计量比,球磨1h后移入电阻炉中在700℃煅烧3 h,即可制备出粒径约为50 nm纯的CoFe2O4粉末。在16~20 GHz电磁波频率范围内测试了不同厚度样品的吸波性能,当样品的厚度为3 mm时,其反射率值最小为-8.6dB,表明样品具有较好的吸波性。此外将纳米铁氧体粉末在浓度为1.0%的六偏磷酸钠溶液中进行超声分散30min,有助于改善纳米铁氧体的团聚现象。高性能水泥复合吸波材料影响因素的研究结果表明,当掺加20%粉煤灰和15%矿粉时,水泥砂浆的强度最高,电阻率较小,吸波性最好;采用玻化微珠制备的水泥砂浆,其抗压强度比采用膨胀珍珠岩的砂浆强度高,电阻率小;当复掺3%石墨和3%纳米铁氧体时,混凝土在低频和高频段均具有较好的吸波性。粘土陶粒轻骨料混凝土和浮石轻骨料混凝土的抗压强度相近,但后者的电阻率比前者的电阻率小,且吸波性好;在混凝土中掺加1%的钢纤维不仅能提高其抗压强度,降低电阻率,且大大改善其吸波性能。综合上述试验结果,确定出制备C20高性能水泥基复合吸波材料的配合比为:水泥:粉煤灰:矿粉:纳米铁氧体:石墨:玻化微珠:浮石:钢纤维:减水剂:分散剂:水=65:20:15:3:3:14.6:124:12.7:1:0.6:50。
[Abstract]:With the development of digital communication system and the wide application of various electronic devices, electromagnetic radiation pollution has become a new social hazard. In view of the deteriorating electromagnetic environment and the requirements of military stealth and protection, it is of great significance to study the cement-based composite absorbing materials with wide band, high efficiency and satisfying the structural load requirements. Aiming at the problems of low absorptive efficiency, high quality, high cost, poor stability and low bearing capacity of cement based composite absorbing materials, this paper makes a comprehensive design from the aspects of impedance matching, wave absorbing efficiency and structure carrying capacity. The preparation method of nanometer CoFe2O4 absorbent was discussed at first, and then the kinds of admixture, porous aggregate, absorbent, fiber and the strength of high performance cement composite absorbing material were discussed. The influence of resistivity and absorbing property. The results showed that the raw materials cobalt nitrate, ferric nitrate and sodium hydroxide and dispersant polyvinyl alcohol were ball-milled for 1 h and then calcined at 700 鈩，
本文编号：2295431
[Abstract]:With the development of digital communication system and the wide application of various electronic devices, electromagnetic radiation pollution has become a new social hazard. In view of the deteriorating electromagnetic environment and the requirements of military stealth and protection, it is of great significance to study the cement-based composite absorbing materials with wide band, high efficiency and satisfying the structural load requirements. Aiming at the problems of low absorptive efficiency, high quality, high cost, poor stability and low bearing capacity of cement based composite absorbing materials, this paper makes a comprehensive design from the aspects of impedance matching, wave absorbing efficiency and structure carrying capacity. The preparation method of nanometer CoFe2O4 absorbent was discussed at first, and then the kinds of admixture, porous aggregate, absorbent, fiber and the strength of high performance cement composite absorbing material were discussed. The influence of resistivity and absorbing property. The results showed that the raw materials cobalt nitrate, ferric nitrate and sodium hydroxide and dispersant polyvinyl alcohol were ball-milled for 1 h and then calcined at 700 鈩，
本文编号：2295431
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