合金元素Cr,Al对Sn-Ag-Cu基无铅钎料高温抗氧化和润湿性的影响

研究了少量合金元素Cr，Al对Sn-3．0Ag-0．5Cu（305）无铅钎料高温抗氧化性的影响。钎料在液态下的表面颜色变化以及热重分析表明，Cr，Al能明显改善305合金钎料的抗氧化性能。通过合金元素Cr，AI的抗氧化机制和X射线衍射分析得出：Al和Cr在钎料表面形成致密氧化膜，形成“阻挡层”，抑制了钎料的氧化。同时也比较了合金元素Cr，Al对305钎料润湿性能的影响，结果表明：单独加Al不利于钎料的铺展，少量的Cr和Al同时加入对钎料的铺展没有太大的影响。实验证实：Cr和Al的共同作用明显提高了Sn-3．0Ag-0．5Cu钎料的高温抗氧化性，同时对钎料的润湿性也没有恶化作用。

Effect of Alloying Elements Cr, Al on High-Temperature Oxidation Resistance and Wettability of Sn-Ag-Cu Based Lead-Free Solder

The effect of alloying elements Cr, AI on the oxidation resistance of Sn-3.0Ag-0.5Cu lead-free solder at high temperature was studied. The changes of solders surface color at high temperature and TGA indicate that adding AI and Cr can significantly im- prove the oxidation resistance of Sn-3.0Ag-0.5Cu lead-free solder. The anti-oxidation mechanisms and XRD of alloying elements Cr, AI were further analysed, indicating that AI and Cr are concentrated at the surface of the solder and form a layer of dense oxide scale, which act as an oxidation barrier, prevent the solders from further oxidation. The effect of Cr, A; alloying elements on the wettability of Sn-3.0Ag-0.5Cu solder were compared and the results indicate that AI alone worsens the wettability of solder, but both Cr and AI in small quantities do not have effect on the wettability of Sn-3.0Ag-0.5Cu solder. It is concluded that Cr and AI in common improve the oxidation resistance of Sn-3.0Ag-0.5Cu solder at high temperature and do not deteriorate the wettability of solder.