One continual question from customers (and it's a reasonable one) is why there are so few choices available for solder alloys, when there are so many elements in the periodic table. This seems like fair comment, until you consider how few of the elements in the periodic table have the following set of characteristics:
- Metals or borderline-metals
- Unreactive or only moderately reactive with moisture or oxygen
- Melting point from ~200 to ~600degC
- Inexpensive
- High electrical and thermal conductivity
- Some degree of malleability (non-brittle)
- Low toxicity / carcogenicity
We have defined what we call the "Periodic Table of Solder", shown on the right, which is just one way of illustrating the paucity of possibilities for solder usage. Throw in the need for the alloy to have a solidus above 270degC, and the possibilities really shrink down. The drive towards Pb-free in European automotive electronics is a significant challenge, but Dr Ning-Cheng Lee (VP of Research and Development) and his R&D team are working on it, even as I type. More updates in the next several weeks.
Cheers!