水泥基材料离子热电效应与机制  

Ionic thermoelectric effect and mechanism of cement-based materials

作　　者：崔一纬 王亚琼[2] 魏亚[1] CUI Yiwei;WANG Yaqiong;WEI Ya(Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry,Department of Civil Engineering,Tsinghua University,Beijing 100084,China;School of Highway,Chang’an University,710046 Xi’an,Shaanxi Province,China)

机构地区：[1]清华大学土木工程系土木工程安全与耐久教育部重点实验室,北京100084 [2]长安大学公路学院,西安710064

出　　处：《复合材料学报》2022年第1期302-312,共11页Acta Materiae Compositae Sinica

基　　金：国家重点研发计划(2018YFB1600200)。

摘　　要：当前水泥基材料热电效应主要通过掺入大量功能填料来增强。但掺量过高的功能填料提高了水泥基复合材料的成本,劣化了其力学性能,阻碍其大范围的应用。本研究发现,由于孔隙溶液中存在大量自由移动的离子,不掺任何功能填料的水泥净浆表现出显著的离子热电效应。本研究通过对比水泥净浆干燥前后的热电压,研究了水泥基材料的离子热电效应,并通过离子浸出与饱和碱溶液实验对水泥净浆的离子热电效应机制进行了探究。结果表明,由于孔隙溶液中OH^(-)的热扩散,干燥前水泥净浆表现出显著的n-type离子热电效应。离子浸出过程中OH^(-)浓度的降低导致水泥净浆的离子热电特性由n-type转变为p-type。饱和碱溶液后,在OH^(-)浓度较大时,阳离子种类亦会对离子热电特性产生显著影响。此外,未添加功能性填料的水泥净浆的Seebeck系数可达1.133 mV·℃^(-2),功率因数(PF)可达0.042μW·m^(-1)·℃^(-2),高于文献中一些功能性填料掺量达5%的水泥基复合材料,具有显著的热电转换效率。At present,the thermoelectric effect of cement-based materials is mainly enhanced by adding a large amount of functional fillers.However,the high content of the functional filler increases the cost,degrades their mechanical properties and hinders their wide application.It is found in this study that the pure cement paste without any functional fillers shows a significant ionic thermoelectric effect due to the freely moving ions in the pore solution of the cement-based materials.The ionic thermoelectric effect of the cement-based materials was studied by comparing the thermoelectric voltage of pure cement paste before and after drying,and the mechanism of the ionic thermoelectric effect of pure cement paste was further explored through ion leaching and saturated alkali solution experiments.Results show that the pure cement paste before dry shows a significant n-type ionic thermoelectric effect due to the thermal diffusion of OH^(-).The decrease of the concentration of OH^(-)in the leaching process leads to the change of ionic thermoelectric voltage from n-type to p-type.After saturated in NaOH solution,the type of cations has a significant effect on the ionic thermoelectric properties even under the condition of high OH^(-)concentration.In addition,the Seebeck coefficient of cement paste without any functional filler can reach1.133 mV·℃^(-2),and the power factor PF can reach 0.042μW·m^(-1)·℃^(-2),which is higher than that of some cement-based composites with 5%functional filler in the literature.

关 键 词：离子热电效应 水泥基材料 离子浓度 SEEBECK系数 离子浸出 

分 类 号：TB332[一般工业技术—材料科学与工程]