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本文根据含铅焊料Pb36.32Sn58.68Bi5在温度诱导下发生液-液结构转变,且具有不可逆性,在发生不可逆液-液结构转变后的Pb36.32Sn58.68Bi5熔体中,其结晶形核率和凝固过冷度较发生转变前增大,初生相和共晶相组织明显细化;Pb-Pb共价键基本消失,取而代之的是Pb-Sn和Pb-Bi共价键,在焊接过程中抑制了铅的挥发,从而减小了铅的污染;另外,转变后的该种焊料在H2SO4溶液、NaOH溶液和NaCl溶液中的耐腐蚀性有明显提高。文中还就相关作用机理进行了讨论。
In this paper, the Pb36.32Sn58.68Bi5 lead-containing solder has temperature-induced liquid-liquid structure change and irreversibility. In the Pb36.32Sn58.68Bi5 melt after the irreversible liquid-liquid structure transformation, the crystallization rate And the degree of solidification undercooling increased before the transformation. The microstructure of primary phase and eutectic phase was obviously refined. The covalent bond of Pb-Pb basically disappeared and replaced by the covalent bond of Pb-Sn and Pb-Bi. During the welding process Inhibit the volatilization of lead, thus reducing the lead pollution; In addition, the transition of the solder in H2SO4 solution, NaOH solution and NaCl solution significantly improved corrosion resistance. The article also discussed the mechanism of action.