| 摘要 |
PURPOSE: Lead-free alloy for soldering is provided to minimize damage from lead poisoning and prevent environmental pollution by using the lead-free alloy, and to improve working efficiency and hardness by adding copper, nickel, phosphorus and gallium to tin. CONSTITUTION: Lead-free solder alloy for fastening parts in a substrate in manufacturing electric and electronic products is composed of copper of 0.1 to 2.0 wt%, nickel of 0.02 to 1.0 wt%, phosphorus of 0.002 to 1.0 wt%, gallium of 0.01 to 1.0 wt% and tin. Tin improves the wettability to the base metal without toxicity, and improves bonding rigidity by refining grains of alloy and restricts corrosion of the printed circuit board or the electronic components. Phosphorus is added to the lead-free alloy to prevent oxidation, and floated up in melting to minimize dross by forming the film contacted to oxygen among air. The melting point is decreased, and mechanical characteristics are increased by adding gallium to the lead-free alloy.
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