- 學位論文
量化電弧放電法製備奈米銀流體過程與懸浮穩定性分析
Quantification of Arc Discharge Processing on Silver Nanofluid Fabrication and Suspension Stability Analysis
摘要
電弧放電法製備奈米流體的基本原理乃利用電弧集中之能量將電極表面塊材融化、濺射冷卻出奈米等級之顆粒被超純水收集並懸浮，本研究主要是量化放電過程所產生之顆粒、離子的濃度與電弧能量之量化，最後分析懸浮奈米銀顆粒穩定性。故本研究分成二部分，第一部分為量化製備奈米銀流體過程，透過精密天秤與滴定儀，量化不同設定之放電-休止週期(On-off Duration)對應之顆粒與離子濃度上升的速率。而能量量化部分，成功透過放電成功率與中央極限定理估算電弧所產生之能量；第二部分為奈米銀流體之懸浮穩定性分析，利用可見光-紫外光光譜儀與Zeta-Sizer分析奈米銀流體懸浮穩定性與顆粒、離子濃度之間的關係。證明顆粒濃度達到飽和對穩定度影響大於離子濃度達到飽和。縮短潛弧製備時間改善穩定度有限，仍在12 Hr內聚集沉澱。而Zeta-potential與pH分析結果顯示添加分散劑Citric Acid為有效使懸浮穩定性上升的方法。
並列摘要
The principal of arc discharge fabricating theorem is using the concentrated arc energy to melt the electrodes surface, then spraying, quenched, and suspended immersed into the dielectric solution (pure water). In this research, the main purpose is to quantificate the particle and ionic silver concentration arising rate, finally, the silver nanofluid suspension stability been analized. Therefore, this research could be separated into two issues. The 1st issue is “quantificating the arc discharge processing on silver nanofluid fabrication.” By using the precision scale and titrator, under different on-off duration setting, the silver particle and ionic silver had been quantification. For the arcing energy quantification issue, once, take arcing rate and central-limit-theorem into consideration could successfully realize arcing energy calculation technique. The 2nd issue is “nanofluid suspension stability analysis.” By using UV-Visible-spectrum-meter and Zeta-sizer, the result shows, the saturated concentration of silver nanoparticle, but not the ionic silver, surely reduces the suspension stability. In this study, without adding any dispersant, only adjust the total arc discharge processing time. Thus the Zeta-potential vs. pH experimental result shows, the suspension stability of shorter processing time is still slightly worse than adding 2 ppm citric acid.