本文選題：石墨烯粉末 + 瞬態(tài)電熱技術��； 參考：《青島理工大學》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,在粉末材料面內方向導熱系數的確定上,多數測量方法中存在一定的局限性。本文采用瞬態(tài)電熱技術測量了微尺度下石墨烯粉末面內方向的熱擴散率并推導出相應的本征導熱系數,有效避免了測量時的厚度局限問題。借助導熱系數測試儀(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方向的導熱系數,分析了含水率、密度、預熱溫度對石墨烯粉末導熱系數的影響,揭示了相應的導熱機理,為石墨烯粉末的熱應用提供了科學依據。采用瞬態(tài)電熱技術測量了密度為0.24 g/cm~3的5-6層純石墨烯粉末面內方向的熱擴散率,其值為0.86×10~(-5)-1.52×10~(-5) m~2 s~(-1),相應的本征導熱系數為13.5-23.8W/(m·K)�；诟牧嫉乃矐B(tài)平面熱源法測得了石墨烯粉末垂直于面內方向的導熱系數為18.8 W/(m·K)。使用導熱儀研究了含水率對石墨烯粉末導熱性能的影響。實驗結果顯示石墨烯粉末的導熱系數隨含水率的增加而顯著增加,當含水率達到92.3%時,混合物(石墨烯與水)的導熱系數提高了60%。通過保持體積不變,不斷增加質量的方法改變石墨烯粉末樣品密度。使用導熱儀測量了不同密度下石墨烯粉末導熱系數的變化情況,發(fā)現其導熱系數與密度成正比。在密度從0.02g/cm~3增加到0.22g/cm~3時,導熱系數總體提升了8.09%。為研究預熱溫度對石墨烯導熱系數的影響,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熱,結果表明不同預熱溫度處理后,冷卻到室溫的各樣品導熱系數的值無明顯變化,與室溫22℃下的值基本相同。即在50℃-300℃的加熱溫度范圍內冷卻到室溫后的石墨烯粉末的導熱系數不受預熱溫度的影響。
[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