以電漿電弧製備奈米碳流體之最佳化研究
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2013
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摘要
本研究使用電漿電弧設備以氣凝法生產碳奈米流體。碳奈米流體生產的方式是以電漿電弧加熱石墨靶材，藉由氬氣將氣化的碳蒸汽凝結並輸送到蒐集槽的水中形成碳奈米流體。在奈米碳的形貌與粒徑方面分別以掃描式電子顯微鏡與穿透式電子顯微鏡分析碳奈米微粒的形貌與一次粒徑，並使用雷射散射粒徑分析儀進行懸浮於水中的碳微粒之二次粒徑量測。接著利用田口式實驗設計法的望小值分析與直交表L9排列找出最具影響的參數因子。以流體密度經驗公式計算出碳奈米流體的濃度的含碳量，再以光譜儀量測碳奈米流體在不同光波長的吸收值，經由比對獲得碳奈米流體濃度與吸收值之間的關係。研究結果顯示，本碳奈米流體製造設備可以成功地製造出粒徑在200~400 nm之間的碳奈米微粒，最佳化粒徑為273 nm。最具影響的製程參數因子為脈衝頻率及電漿氣體流量，最佳值分別為5 Hz與1.5 LPM，貢獻率則分別為48.90 %和13.14 %。在脈衝頻率5 Hz及電漿氣體流量1 LPM下發現所製備出的碳奈米微粒有奈米碳管的存在。在光學吸收值與濃度關係分析中可以發現在900 nm波長時的吸收值與奈米碳流體濃度呈現線性關係。該關係所繪製出的檢量線可用於未來本製造系統在生產碳奈米流體時可進行快速定量分析。
Abstract The purpose of the present paper is to obtain carbon nanofluid based on gas condensation methods utilizing plasma arc welding machine. The plasma arc provides the extreme high temperature inside the vaporization chamber, which melts and evaporates the graphite rods. Then the argon (Ar) carries carbon vapor and particles to a collector, where the carbon nanofluid is formed.SEM and TEM were used to analyze the microstructural properties and the particle size. The suspended particle size were measured by a laser-scattering particle size analyzer. The SN ratio and Orthogonal Arrays (OA) L9 of Taguchi methods determined the optimal manufacturing parameters. In order to obtain the carbon content of carbon nanofluid, it is substituted in Fluid formula. Afterward, measured the absorbance at different wavelengths and compared the relation between absorbance and the density of carbon nanofluid. The result shows that the size between 200nm and 400nm of carbon nanofluid is able to be produced by using plasma arc in a one-step synthesis and the optimal size is 273nm. The optimal manufacturing parameters are pulse frequency and plasma gas flow which best value are 5 Hz and 1.5 LPM, having 48.90% and 13.14% in contribution separately. Our data provides evidence that carbon nanotube exists when pulse frequency and plasma gas flow are under best value. The analysis in absorbance and density of carbon nanofluid indicates that these two have a linear relation. For the further study, the calibration curve of the linear relation can be as basic data for the quickly use of quantitative analysis.
Abstract The purpose of the present paper is to obtain carbon nanofluid based on gas condensation methods utilizing plasma arc welding machine. The plasma arc provides the extreme high temperature inside the vaporization chamber, which melts and evaporates the graphite rods. Then the argon (Ar) carries carbon vapor and particles to a collector, where the carbon nanofluid is formed.SEM and TEM were used to analyze the microstructural properties and the particle size. The suspended particle size were measured by a laser-scattering particle size analyzer. The SN ratio and Orthogonal Arrays (OA) L9 of Taguchi methods determined the optimal manufacturing parameters. In order to obtain the carbon content of carbon nanofluid, it is substituted in Fluid formula. Afterward, measured the absorbance at different wavelengths and compared the relation between absorbance and the density of carbon nanofluid. The result shows that the size between 200nm and 400nm of carbon nanofluid is able to be produced by using plasma arc in a one-step synthesis and the optimal size is 273nm. The optimal manufacturing parameters are pulse frequency and plasma gas flow which best value are 5 Hz and 1.5 LPM, having 48.90% and 13.14% in contribution separately. Our data provides evidence that carbon nanotube exists when pulse frequency and plasma gas flow are under best value. The analysis in absorbance and density of carbon nanofluid indicates that these two have a linear relation. For the further study, the calibration curve of the linear relation can be as basic data for the quickly use of quantitative analysis.
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Keywords
奈米流體, 田口式實驗設計法, 電漿電弧, Nano-fluid, Taguchi method, Plasma Arc