What are the differences between lead-free solder and traditional lead solder? What are the benefits?
Release Date：2018-03-30
What are the differences between lead-free solder and traditional lead solder? What are the benefits?
Lead free solder contains no lead and has a higher melting point than traditional (63% tin, 37% lead) solder. The melting point range of lead-free solder is approximately from 217 ℃ to 226 ℃. The benefits include: 1. Good electrical and thermal conductivity. 2. Smaller solid-liquid coexistence range: Most experts recommend controlling this temperature range within 10 ℃ to form good solder joints. If the alloy solidification range is too wide, solder joint cracking may occur, causing premature damage to electronic products. 3. Low toxicity: The alloy composition must be non-toxic. 4. Has good wetting properties. 5. Good physical properties (strength, tension, fatigue): The alloy must be able to provide the strength and reliability that Sn63/Pb37 can achieve, without protruding fillet welds on through-hole devices. 6. Repeatability of production and consistency of solder joints: As electronic assembly technology is a large-scale manufacturing process, it is required to maintain a high level of repeatability and consistency. If certain alloy components cannot be produced in large quantities Repeated production or significant changes in melting point due to changes in composition during mass production cannot be considered. 7. Appearance of solder joints: The appearance of solder joints should be similar to that of tin/lead solder. 8. Compatibility with lead: Due to the fact that it will not be fully transitioned to lead-free in the short term, lead may still be used on PCB pads and component terminals. If lead is added to the solder, it may significantly lower the melting point of the solder alloy, Greatly reduced intensity
