Effects of graphite on the mechanical and microwave absorption properties of geopolymer based composites
Effects of graphite on the mechanical and microwave absorption properties of geopolymer based composites
复制标题
石墨对地质聚合物基复合材料机械和微波吸收性能的影响
DOI：
10.1016/j.ceramint.2016.11.017
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发表时间：
2017
影响因子：
5.2
通讯作者：
Yu Zhou
中科院分区：
文献类型：
--
作者：
Yao Zhang;Peigang He;Jingkun Yuan;Chao Yang;Dechang Jia;Yu Zhou
本文首先将石墨/偏高岭土球磨得到均匀的粉末，然后将其与硅酸钾溶液通过机械搅拌混合。固化后，得到石墨/地质聚合物复合材料，石墨与地质聚合物的比例为0 ~ 18，部分样品在600 °C下进一步热处理。系统研究了石墨含量对复合材料力学性能和微波吸收性能的影响。结果表明，当石墨与地质聚合物的质量比不大于12时，石墨在复合材料中分散均匀。然而，当石墨与地质聚合物的比例为15和18时，注意到石墨团聚。随着石墨与地聚合物比例的增加，复合材料的弯曲强度和断裂韧性先增加，达到峰值后下降。当石墨与地聚合物的质量比为12时，复合材料的弯曲强度和断裂韧性最高，这是由于石墨的力学性能远高于地聚合物基体，这是由复合材料的混合规律决定的。随着石墨含量的增加，复合材料的介电常数逐渐增大，而磁常数基本不变。这表明复合材料的主要吸波机理是介电损耗。复合材料的最大波反射损耗与其力学性能有相似的变化趋势。当石墨与地聚合物的质量比为12时，其强度达到峰值，随后开始下降，这也可能与石墨的团聚有关。在600 °C热处理后，观察到反射损耗峰值略微下降，并且对应于最大反射损耗的厚度明显减小。
In this paper graphite/metakaolin was first ball-milled to get homogeneous powder, which was then mixed with potassium silicate solution through mechanically stirring. Post curing, we got graphite/geopolymer composites with graphite to geopolymer ratio from 0 to 18 and part the samples were further dealt with heat treatment at 600 °C. Effects of the graphite content on the mechanical properties and microwave absorption properties of the composites were systematically investigated. The results proved that when graphite to geopolymer ratio is not higher than 12, graphite dispersed homogeneously in the composites. However, graphite agglomeration was noted when graphite to geopolymer ratios are 15 and 18. With the increase in graphite to geopolymer ratio, flexural strength and fracture toughness of the composites first increased, reaching the peak value and then decreased. When the graphite to geopolymer ratio is 12, the composite showed the highest flexural strength and fracture toughness, which should be explained by the mixing rule of composites since the mechanical properties of graphite are much higher than geopolymer matrix. With the increase in graphite content, the dielectric constants of the composite increased gradually, but the magnetic constants nearly kept unchanged. It implied that the main microwave absorbing mechanism would be dielectric loss of the composites. The maximum wave reflection loss showed similar trend to the mechanical properties of composites. It reached the peak value when graphite to geopolymer ratio is 12 and then started to decline, which might also be related to the graphite agglomeration. After 600 °C heat treatment, slight decline of the reflect loss peak and obvious decrease on the thickness corresponding to the maximum reflection loss were observed.