本文選題：石墨烯粉末 + 瞬態(tài)電熱技術(shù)��； 參考：《青島理工大學(xué)》2016年碩士論文

【摘要】：石墨烯是碳材料界的新興材料,具有優(yōu)異的導(dǎo)熱性能,有效測量并深入研究其熱物性意義重大。由于微尺度下石墨烯尺寸較小,無法運用傳統(tǒng)熱物性測量方法加以測量,且目前關(guān)于粉末形態(tài)的石墨烯熱傳輸特性研究尚淺。另外,在粉末材料面內(nèi)方向?qū)嵯禂?shù)的確定上,多數(shù)測量方法中存在一定的局限性。本文采用瞬態(tài)電熱技術(shù)測量了微尺度下石墨烯粉末面內(nèi)方向的熱擴散率并推導(dǎo)出相應(yīng)的本征導(dǎo)熱系數(shù),有效避免了測量時的厚度局限問題。借助導(dǎo)熱系數(shù)測試儀(基于改良的瞬態(tài)平面熱源法)測量了石墨烯粉末垂直于面內(nèi)方向的導(dǎo)熱系數(shù),分析了含水率、密度、預(yù)熱溫度對石墨烯粉末導(dǎo)熱系數(shù)的影響,揭示了相應(yīng)的導(dǎo)熱機理,為石墨烯粉末的熱應(yīng)用提供了科學(xué)依據(jù)。采用瞬態(tài)電熱技術(shù)測量了密度為0.24 g/cm~3的5-6層純石墨烯粉末面內(nèi)方向的熱擴散率,其值為0.86×10~(-5)-1.52×10~(-5) m~2 s~(-1),相應(yīng)的本征導(dǎo)熱系數(shù)為13.5-23.8W/(m·K)。基于改良的瞬態(tài)平面熱源法測得了石墨烯粉末垂直于面內(nèi)方向的導(dǎo)熱系數(shù)為18.8 W/(m·K)。使用導(dǎo)熱儀研究了含水率對石墨烯粉末導(dǎo)熱性能的影響。實驗結(jié)果顯示石墨烯粉末的導(dǎo)熱系數(shù)隨含水率的增加而顯著增加,當(dāng)含水率達到92.3%時,混合物(石墨烯與水)的導(dǎo)熱系數(shù)提高了60%。通過保持體積不變,不斷增加質(zhì)量的方法改變石墨烯粉末樣品密度。使用導(dǎo)熱儀測量了不同密度下石墨烯粉末導(dǎo)熱系數(shù)的變化情況,發(fā)現(xiàn)其導(dǎo)熱系數(shù)與密度成正比。在密度從0.02g/cm~3增加到0.22g/cm~3時,導(dǎo)熱系數(shù)總體提升了8.09%。為研究預(yù)熱溫度對石墨烯導(dǎo)熱系數(shù)的影響,依次對密度恒定為0.045 g/cm~3的石墨烯粉末樣品在50℃-300℃(11個溫度點逐漸遞增)的溫度條件下分別進行預(yù)熱,結(jié)果表明不同預(yù)熱溫度處理后,冷卻到室溫的各樣品導(dǎo)熱系數(shù)的值無明顯變化,與室溫22℃下的值基本相同。即在50℃-300℃的加熱溫度范圍內(nèi)冷卻到室溫后的石墨烯粉末的導(dǎo)熱系數(shù)不受預(yù)熱溫度的影響。
[Abstract]:Graphene is a new material in the field of carbon materials, which has excellent thermal conductivity. It is of great significance to effectively measure and study the thermal properties of graphene. Because of the small size of graphene in microscale, it can not be measured by traditional thermal physical property measurement method, and the study on the thermal transfer characteristics of graphene powder morphology is still shallow. In addition, there are some limitations in the determination of in-plane thermal conductivity of powder materials. In this paper, the in-plane thermal diffusivity of graphene powder is measured by transient electrothermal technique and the corresponding intrinsic thermal conductivity is derived, which effectively avoids the thickness limitation problem in the measurement. The thermal conductivity of graphene powder perpendicular to the plane was measured by means of a thermal conductivity tester (based on the improved transient plane heat source method). The effects of moisture content, density and preheating temperature on the thermal conductivity of graphene powder were analyzed. The heat conduction mechanism is revealed, which provides a scientific basis for the thermal application of graphene powder. The in-plane thermal diffusivity of 5-6 layers of pure graphene powder with density of 0.24 g/cm~3 has been measured by transient electrothermal technique. Its value is 0.86 脳 10 ~ (-5) ~ (-5) -1.52 脳 10 ~ (10) ~ (-5) m ~ (2) 路s ~ (-1) ~ (-1), and the corresponding intrinsic thermal conductivity is 13.5-23.8W/(m ~ (-1). Based on the improved transient plane heat source method, the thermal conductivity of graphene powder perpendicular to the in-plane direction is measured to be 18.8 W / m KN. The effect of moisture content on thermal conductivity of graphene powder was studied by means of thermal conductivity instrument. The experimental results show that the thermal conductivity of graphene powder increases significantly with the increase of moisture content. When the moisture content reaches 92.3, the thermal conductivity of the mixture (graphene and water) increases by 60%. The density of graphene powder samples was changed by keeping the volume constant and increasing the mass. The thermal conductivity of graphene powder under different densities was measured by means of a thermal conductivity meter, and it was found that the thermal conductivity was proportional to the density. When the density increased from 0.02g/cm~3 to 0.22g / cm ~ 3, the thermal conductivity increased by 8.09g / cm ~ 3. In order to study the effect of preheating temperature on the thermal conductivity of graphene, the graphene powder samples with constant density of 0.045 g/cm~3 were preheated at 50 鈩，

本文編號：1924792