Solder is the conductive metal glue that one uses to stick components together. If you get the component and the PCB hot enough, and melt a little solder in the joint, it will stay put and conduct reliably. But it’s far from simple.
There are many different solder alloys, and even the tip of the soldering iron itself is a multi-material masterpiece. In this article, we’ll take a look at the metallurgy behind soldering, and you’ll see why soldering tip maintenance, and regular replacement, is a good idea. Naturally, we’ll also touch upon the role that lead plays in solder alloys, and what the effect is of replacing it with other metals when going lead-free. What are you soldering with? Continue reading “The Fascinating World Of Solder Alloys And Metallurgy”→
For most of the history of industrial electronics, solder has been pretty boring. Mix some lead with a little tin, figure out how to wrap it around a thread of rosin, and that’s pretty much it. Sure, flux formulations changed a bit, the ratio of lead to tin was tweaked for certain applications, and sometimes manufacturers would add something exotic like a little silver. But solder was pretty mundane stuff.
Then in 2003, the dull gray world of solder got turned on its head when the European Union adopted a directive called Restriction of Hazardous Substances, or RoHS. We’ve all seen the little RoHS logos on electronics gear, and while the directive covers ten substances including mercury, cadmium, and hexavalent chromium, it has been most commonly associated with lead solder. RoHS, intended in part to reduce the toxicity of an electronic waste stream that amounts to something like 50 million tons a year worldwide, marked the end of the 60:40 alloy’s reign as the king of electrical connections, at least for any products intended for the European market, when it went into effect in 2006.