Lead-free solder alloy

摘要

A lead-free solder alloy includes a tin-copper alloy that also includes a minor amount of cobalt, which has been found to provide a shiny and reflective appearance to the solder alloy. Methods of soldering using such an alloy, as well as a solder joint including such an alloy also are disclosed.

主权项

1. A method of wave soldering comprising the steps of:
a) providing a circuit board having a series of predrilled holes therethrough and a conductive copper coating on the inner surface of said predrilled holes, b) placing an electronic component so that metallic electrical leads thereof extend from a first surface of said circuit board, through said predrilled holes, toward a second surface thereof, c) applying a layer of flux over said second surface of said circuit board, and d) contacting said second surface of said circuit board with a wave of molten lead-free solder alloy so that molten solder alloy from said wave contacts said second surface of said circuit board, activating the flux previously coated thereon and causing lead-free molten solder alloy from said wave to wick up the exposed electrical leads from said second surface into said predrilled holes, to provide a solder joint between said leads and the conductive coating on the interior surfaces of said predrilled holes, said lead-free solder alloy consisting essentially of, by weight, 0.2-2% copper, 0.02-0.3% cobalt, and at least 98% tin.