| 摘要 |
<p>The soldering alloy of Sn-Pb-Ag(0-4%), or Pb-Sn-Ag (0-4%) type contains in addn. 0.5-4 wt.% (0.6-2 wt.%) Zn and/or Cd. Suitable for soldering electrical components which are coated with a noble metal. Pref. compsn. is 56.8-63.2 wt.% Sn, 36.0-40.0 wt.% Pb, 0-2.0 wt.% Ag, 0.8-1.2 wt.% Zn. The alloy does not dissolve the noble metal component of the substrate, and provides a soldered joint of higher strength. The presence of 0.6-2 wt.% pref. 0.8-1.2 wt.% Zn and/or Cd improves the soldering properties and prevents a dissoln. of, e.g., Ag and Pd of the coating. The soldered joint remains ductile. The alloy is suitable for soldering ceramic substrates having a thin coating of a noble metal alloy. Dissoln. of the noble metal is prevented by the formation of an intermetallic Zn or Cd noble metal phase. Contents over 4 wt.% of Zn or Cd are no longer beneficial as the alloy exhibits inferior flow characteristics and the solder produces defective structures.</p> |
