(合肥工业大学 材料科学与工程学院, 合肥 230009)
摘 要: 采用直流四电极法研究了常压下Sn-Zn合金系的电阻率随温度连续升温的变化规律。结果表明: 合金Sn-Zn5、 Sn-Zn8.8、Sn-Zn20、 Sn-Zn30、 Sn-Zn40、 Sn-Zn50和Sn-Zn70分别在970、 1 008、 957、 950、 948、 926和873 ℃处发生了电阻率的突变现象。 对合金的进一步分析表明, Sn-Zn熔体电阻率在高温时的突变是由Zn在Sn-Zn熔体中大量汽化造成的, 即在此处发生了液-气结构转变; Sn-Zn合金在完全熔化至发生液-气结构转变的连续升温过程中, 合金中并不存在某种液-液结构的转变, 且液-液结构转变并非存在于在所有二元合金系中。
关键字: Sn-Zn合金; 液态结构; 电阻率; 汽化
temperature of Sn-Zn alloys
(College of Materials Science and Engineering,
Hefei University of Technology, Hefei 230009, China)
Abstract: The change rule of electrical resistivity with the increase of temperatures of tin-zinc (Sn-Zn) alloys with different compositions were investigated using the direct current four-probe technique at constant pressure. The results show that some transitions occur at the temperatures of 970, 1 008, 957, 950, 948, 926 and 873 ℃. According to the analysis of the resistivity—temperature (ρ—t) curves, the obtained significant abnormal variation of the electrical resistivity at high temperature of Sn-Zn alloys is considered to be caused by the abundant gasification of Zn component in Sn-Zn alloys, namely the liquid-gas structure transition takes place in melts. And no temperature-induced liquid-liquid structure transition exists in Sn-Zn melts.
Key words: Sn-Zn alloys; liquid structure; electrical resistivity; vaporization