本文選題：EGCFRC　切入點(diǎn)：熱電性能　出處：《西安建筑科技大學(xué)》2017年碩士論文

【摘要】：膨脹石墨/碳纖維增強(qiáng)水泥基復(fù)合材料(Expanded Graphite/Carbon Fiber Reinforced Cement-based Composites,簡(jiǎn)寫為EGCFRC)是一種可以實(shí)現(xiàn)熱電相互轉(zhuǎn)換的新型功能材料。它在城市余熱利用、建筑結(jié)構(gòu)健康監(jiān)測(cè)和道路低能耗融雪化冰領(lǐng)域具有廣泛的應(yīng)用前景,是智能水泥基復(fù)合材料研究與發(fā)展的重要方向之一。但目前,EGCFRC-Seebeck系數(shù)仍然較低,是制約其大規(guī)模應(yīng)用的關(guān)鍵因素。本文主要通過壓制成型工藝制備EGCFRC,分析不同成型壓力對(duì)EGCFRC電導(dǎo)率與Seebeck效應(yīng)的影響。利用體視學(xué)方法實(shí)現(xiàn)了EGCFRC中碳纖維/膨脹石墨與水泥基體間界面,孔隙和微裂紋形成的氣/固界面的定量化表征。探究了含水率、不同類型氣/固界面,金屬氧化物/水泥基體界面以及離子液體/水泥基體界面對(duì)EGCFRC電導(dǎo)率及Seebeck系數(shù)的影響,獲得了EGCFRC多類型界面散射強(qiáng)化機(jī)理。主要研究?jī)?nèi)容和結(jié)果如下:(1)借助圖像分析方法獲得了EGCFRC基體中碳纖維/膨脹石墨與水泥基體間界面,微/納米孔隙或微裂紋與水泥基體間氣/固界面的二維信息,利用體視學(xué)原理推導(dǎo)出EGCFRC定量化的三維信息,并建立界面參數(shù)與EGCFRC電導(dǎo)率、Seebeck系數(shù)間的數(shù)學(xué)關(guān)系。研究結(jié)果表明:EGCFRC的電導(dǎo)率隨成型壓力的增大而呈增加趨勢(shì);而EGCFRC中氣/固界面含量則隨著成型壓力的減小而增大,從而引起基體中缺陷密度變大,載流子傳輸受阻,Seebeck效應(yīng)獲得強(qiáng)化。成型壓力為60 MPa時(shí)最利于EGCFRC熱電性能的提高。(2)探討了氣孔率對(duì)EGCFRC熱電性能的影響,并通過層切法構(gòu)造與熱流方向呈不同夾角的氣/固界面,進(jìn)一步獲得氣/固界面對(duì)EGCFRC電導(dǎo)率與Seebeck效應(yīng)的影響機(jī)理。研究結(jié)果表明:采用壓制成型制備EGCFRC,成型壓力為60 MPa時(shí),EGCFRC獲得最大電導(dǎo)率0.063 S·cm~(-1),較傳統(tǒng)成型工藝提高了3個(gè)數(shù)量級(jí)。同時(shí),獲得最大功率因數(shù)7.26×10~(-4)μWm-1K-2以及最大ZT值2.22×10-7。20 MPa,40 MPa和60 MPa三種成型壓力下,氣/固界面與熱流方向呈90o夾角時(shí),EGCFRC的Seebeck效應(yīng)得到強(qiáng)化,其中,成型壓力為20 MPa時(shí)效果最顯著。(3)測(cè)量了EGCFRC樣品的含水率,研究了含水率對(duì)EGCFRC熱電性能的影響。研究結(jié)果表明:含水率的增大可以強(qiáng)化Seebeck效應(yīng),但也會(huì)降低電導(dǎo)率。在33oC時(shí),當(dāng)EGCFRC中含水率為14.98%時(shí),獲得最大的絕對(duì)Seebeck系數(shù)11.59μV/oC。在同一溫度下,當(dāng)含水率為11.44%時(shí),獲得最大的電導(dǎo)率0.078 S·cm~(-1)以及最大的功率因數(shù)7.85×10~(-4)μWm-1K-2。含水率對(duì)EGCFRC熱電性能的顯著影響可以歸因于接觸電阻的存在、載流子散射、水泥基體的極化效應(yīng)以及EGCFRC固有的高密度缺陷界面。(4)探討了水泥基體中Fe_2O_3含量對(duì)EGCFRC熱電性能的影響。研究結(jié)果表明:Fe_2O_3摻量為5.0 wt%時(shí),EGCFRC的電導(dǎo)率和Seebeck效應(yīng)同時(shí)得到提高,在65oC時(shí)獲得最大絕對(duì)Seebeck系數(shù)16.80μV/oC和最大電導(dǎo)率0.084 S·cm~(-1);而加入10.0wt%的Fe_2O_3時(shí),EGCFRC的絕對(duì)Seebeck系數(shù)最大可達(dá)20.85μV/oC,但電導(dǎo)率卻只有0.036 S·cm~(-1)。(5)研究了不同養(yǎng)護(hù)方式、離子液體[Bmim]Br摻量對(duì)EGCFRC熱電性能的影響規(guī)律及機(jī)理。研究結(jié)果表明:離子液體[Bmim]Br摻量越高,EGCFRC的絕對(duì)Seebeck系數(shù)越大,電導(dǎo)率越低。預(yù)處理后養(yǎng)護(hù)可以使[Bmim]Br同時(shí)受到機(jī)械力與熱運(yùn)動(dòng)的雙重作用而更加均勻地分散在水泥基體中,促進(jìn)陰陽離子在電極表面的遷移與重排,從而強(qiáng)化EGCFRC的Seebeck效應(yīng),但同時(shí)會(huì)引起電導(dǎo)率降低。[Bmim]Br摻量為3.0 wt%時(shí),直接養(yǎng)護(hù)EGCFRC在72oC時(shí)獲得最大絕對(duì)Seebeck系數(shù)115.39μV/oC,最大功率因數(shù)8.56×10-3 mWm-1K-2;預(yù)處理后養(yǎng)護(hù)EGCFRC在72oC時(shí)獲得最大絕對(duì)Seebeck系數(shù)580.10μV/oC,最大功率因數(shù)9.97×10-2mWm-1K-2。
[Abstract]:The expanded graphite / carbon fiber reinforced cement composite (Expanded Graphite/Carbon Fiber Reinforced Cement-based Composites, abbreviated as EGCFRC) is a new type of functional material can achieve the thermoelectric conversion. It makes use of waste heat in the city, structural health monitoring and low energy consumption of road deicing field has a wide application prospect, is one of the important research direction with the development of smart cement based composite materials. But at present, the EGCFRC-Seebeck coefficient is still low, is the key factor that restricts its large-scale application. This paper mainly through the preparation of EGCFRC molding process, analysis of the influence of different molding pressure on the conductivity of EGCFRC and Seebeck effect. The stereo implementation of carbon fiber / EGCFRC expanded graphite and cement the matrix interface method, pore and micro crack formation of the gas / solid interface and quantitative characterization. To explore the different types of moisture. Gas / solid interface, effect of metal oxide / cement matrix interface and the ionic liquid / cement matrix interface of EGCFRC conductivity and Seebeck coefficient, obtained the EGCFRC type interface scattering enhancement mechanism. The main research contents and results are as follows: (1) by means of image analysis method for carbon fiber / matrix with EGCFRC expanded graphite and cement the matrix between the two-dimensional information interface, micro / nano pores or cracks and cement matrix between the gas / solid interface, using stereological 3D information derived from the principle of EGCFRC quantification, and establish the interface parameter and EGCFRC conductivity, mathematical relation among the Seebeck coefficients. The results show that the conductivity of EGCFRC increases with the molding pressure and increased; while the EGCFRC gas / solid interface was reduced with the molding pressure increases, causing the defects in bulk density change, carrier transport is blocked, Seebeck effect Gain enhancement. The molding pressure is 60 MPa the most conducive to improve the thermoelectric properties of EGCFRC. (2) discussed the effects of porosity on the thermoelectric properties of EGCFRC, and through slicing method to construct different angles of the gas / solid interface and the heat flow direction, further gas / solid interface on the influence mechanism of the electrical conductivity of EGCFRC and Seebeck effect. Research results indicate that the preparation of EGCFRC press molding, molding pressure is 60 MPa, EGCFRC 0.063 S / cm~ maximum conductivity (-1), increased by 3 orders of magnitude compared with the traditional molding process. At the same time, the maximum power factor of 7.26 * 10~ (-4) Wm-1K-2 and the maximum ZT value of 2.22 * 10-7.20 MPa 40 MPa 60 MPa, and three kinds of molding pressure, gas / solid interface and the heat flow direction is 90o angle, the Seebeck effect of EGCFRC was enhanced, the molding pressure is 20 MPa the most significant effect. (3) EGCFRC water samples were measured, on the moisture content of EG Influence of the thermoelectric properties of CFRC. The results show that the increase of water content can enhance the Seebeck effect, but also can reduce theconductivity. In 33oC, when the water content of EGCFRC is 14.98%, Seebeck get the absolute maximum coefficient of 11.59 V/oC. at the same temperature, when the moisture content is 11.44%, the maximum conductivity 0.078 S - cm~ (-1) and the maximum power factor of 7.85 * 10~ (-4) Wm-1K-2. water content had significant influence on the thermoelectric properties of EGCFRC can be attributed to the contact resistance, carrier scattering, polarization effect of cement matrix and EGCFRC inherent defects with high density interface. (4) to investigate the effect of Fe_2O_3 content in cement matrix the thermoelectric properties of EGCFRC. The results show that the content of Fe_2O_3 is 5 wt%, the conductivity and Seebeck effect of EGCFRC were increased at the same time, in the 65oC and get the maximum absolute Seebeck coefficient of 16.80 V/oC and a maximum conductivity of 0. 084 S - cm~ (-1); while the addition of 10.0wt% of Fe_2O_3, the maximum absolute Seebeck coefficient EGCFRC of 20.85 V/oC, but the conductivity is only 0.036 S - cm~ (-1). (5) studied the different curing methods, ionic liquid dosage of [Bmim]Br on the thermoelectric properties of EGCFRC influence and mechanism research. The results show that the ionic liquid [Bmim]Br content is higher, the absolute Seebeck coefficient of EGCFRC, the lower the conductivity. After pretreatment of maintenance can make the [Bmim]Br at the same time is influenced by both mechanical and thermal motion and more evenly dispersed in the cement matrix, promote the migration and rearrangement of ions in the surface of the electrode, thereby strengthening Seebeck the effect of EGCFRC, but it causes the conductivity decreased the dosage of.[Bmim]Br is 3 wt%, direct maintenance EGCFRC get the maximum absolute Seebeck coefficient of 115.39 V/oC at 72oC, the maximum power factor of 8.56 * 10-3 mWm-1K-2; after the pretreatment of EGCFR maintenance The maximum absolute Seebeck coefficient of 580.10 mu V/oC is obtained at 72oC, and the maximum power factor is 9.97 x 10-2mWm-1K-2.

【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB34

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 朱驥飛;張立;徐濤;張忠健;劉向中;王U，

本文編號(hào)：1729917