| 摘要: | 本研究旨在探討藉由調整超音波空化之參數，以超音波空化法製備次微米級Sn-58Bi焊料粉末之可行性，並進一步分析不同粒徑分布之粉末對其熔化行為之影響。Sn-58Bi共晶合金因具低熔點(139 ℃)與良好的潤濕性，廣泛應用於溫敏元件與低溫焊接工藝中。然而，當焊料粉末之尺寸縮小至次微米尺寸時，因表面能與界面張力會迅速上升，焊料粉末之熔化行為可能產生變化，進而影響後續回流之品質。
本研究利用掃描式電子顯微鏡（SEM）與粒徑分析儀（DLS）確認製備出之Sn-58Bi焊料粉末之尺寸分布，並藉由差示掃描量熱儀（DSC）分析其熔化行為，結果顯示，石蠟油因具高化學穩定性且黏度高，適合用作超音波空化製備焊料粉末的分散液，且隨著空化時間之延長、批次Sn-58Bi焊料粉末量的減少及超音波輸出振幅的提高，製備出之Sn-58Bi焊料粉末尺寸減小且均勻。選擇石蠟油作分散液，並控制空化時間在2 hr，批次Sn-58Bi焊料粉末量為5 g，超音波輸出振幅為30%可成功製備出粒徑小於 1 μm之 Sn-58Bi焊料粉末。除此之外，隨著Sn-58Bi粉末粒徑減小，其熔化起始溫度、熔化峰溫度與熔化過程所吸收之熱皆呈下降趨勢。
;This study aims to investigate the feasibility of fabricating submicron-scale Sn-58Bi solder powders via the ultrasonic cavitation method by adjusting cavitation parameters, and to further analyze the effect of particle size distribution on the melting behavior of the powders. The Sn-58Bi eutectic alloy, known for its low melting point (139 °C) and excellent wettability, is widely used in temperature-sensitive devices and low-temperature soldering processes. However, when the particle size of the solder powder is reduced to the submicron scale, the surface energy and interfacial tension increase significantly, which may alter the melting behavior of the solder powder and affect the quality of subsequent reflow processes.
In this study, we used scanning electron microscopy (SEM) and dynamic light scattering (DLS) to confirm the particle size distribution of the fabricated Sn-58Bi solder powders, while their melting behavior was analyzed using differential scanning calorimetry (DSC). The results showed that paraffin oil, due to its high chemical stability and viscosity, is well-suited as a dispersing medium for solder powder preparation via ultrasonic cavitation. As the cavitation time increased, the batch amount of Sn-58Bi solder powder decreased, and the ultrasonic output amplitude was raised, the resulting solder powders exhibited smaller and more uniform particle sizes. By selecting paraffin oil as the dispersing medium and setting the cavitation time to 2 hours, the batch Sn-58Bi powder amount to 5 g, and the ultrasonic output amplitude to 30%, Sn-58Bi solder powders with particle sizes below 1 μm were successfully produced. Moreover, as the particle size of the Sn-58Bi powders decreased, a downward trend was observed in the onset melting temperature, peak melting temperature, and the enthalpy of fusion. |
