Important Industrial Solder Alloys and Their Uses

Knowing the right solder alloy to use for your application is critical to the success of any project. If the proper solder alloy isn’t chosen and correct plating requirements aren’t defined or flowed, it could result in rework and excessive scrap, or worse the failure of your application. There are many different types of solder alloys and concentrations used for all kinds of applications, but it is important to first have a general understanding of solder and how it works.

Solder is basically a metal wire that has a low melting point (or low enough for melting using a soldering iron). For electronics, solder is usually made from a combination of lead and tin. Tin has a much lower melting point than Lead, which means that higher tin concentrations means a lower solder melting point. Typically, you would find 60Sn/40Pb lead-based solders at gadget stores, although other minor variations are also sold. For industrial purposes, however, you would typically find two major categories of solder alloys, namely, flux cores, and lead-free.

Flux cores further comes in two common forms, such as Acid and Rosin. Acid flux core solder alloys are ideal for plumbing use and cannot/should not be used in electronics as it will likely erode your boards and components. For electronics purposes, choose rosin core. Lead-free alloys are what industry regulations and standards are leaning more towards. Because the EU is now requiring pretty much every commercially available electronics to use lead-free parts and components, this also means more demand for lead-free solders. Lead-free solders pretty much work exactly like lead-based solders, only they are more environmentally friendly. Lead is believed to be a very toxic material, which is why safer metals are now being used in its place. Lead-free solders, however are a lot harder to work with, as replacement metal alloys behave differently and don’t flow as well as lead.