I find low-temperature solder alloys very interesting, especially when I find a new use for them. In this series, I hope to spark an idea in YOUR mind about how a low-temperature alloy might be just the solution you need for the application on which you are working.
Let’s begin with what we mean by “low-temperature solder alloys”. The melting points of these alloys are on the low end of the solder spectrum, but the definition is not precise. Some say that low-temperature solder alloys melt below 350-450°C (depending who you ask). Others feel that any alloys that melt lower than the melting point of 63Sn/37Pb (183°C) are classified as low-temperature solder alloys. It is all relative to whichever alloy the user deems "standard." Many low-temperature alloys include indium, bismuth, and/or gallium, which suppress the melting point. You can learn more about the alloys that are included in this classification by following this link. Some of these alloys have melting points so low, they are liquid at room temperature. The chart below shows some properties of these extremely low-temp alloys.
Check back for more entries on this topic, coming very soon.