There is no direct replacement for Sn/Pb solders that does not involve some form of compromise. While many alternatives with relatively minor changes in reflow temperature, acceptable filltes and wetting has been shown to be less effective. Potentially suitable elements, like bismuth, have to be ruled out for widespread use because they are in short supply, while others are hilghly toxic.
The alternative alloys are necessary to meet the following criteria.

1. Ternary alloys or less. Quarternary alloys can present control difficulties.
   Sn/Zn/Al alloy has only three elements.
   
   
2. Alloy should be near eutectic.
   Sn/Zn Eutectic Temperature is 199°C. Since Aluminum amount is so small, Sn/Zn/Al alloy's melting temperature is still 199°C.
   
   
3. Similar melting temperature as Sn/Pb solders.
   Much lower than Sn/Ag/Cu (see above)
   
   
4. Element with no possible environmental impact now or in the future.
   Toxicity of all three elements (Sn, Zn and Al) is very low.
   
   
5. Sufficient quantities of the elements available now and in the future.
   All three elements (Sn, Zn and Al) are abundant.
   
   
6. Physical properties equal or better than Sn/Pb solders.
   The mechanical properties are much better than Sn/Pb
   
   
7. Good fatigue resistance.
   The Sn/Zn/Al alloy has a good fatigue resistance.
   
   
8. Adequate wettability and solderability.
   The Sn/Zn/Al alloy has a good wettability and solderability.
   
   
9. Compatibility with existing equipment/parts and processes.
   Compatible with existing equipment/parts and processes.
   
   
10. Available in all forms i.e. sphere, bar, paste and wire.
    Sn/Zn/Al is available in sphere, bar, wire and paste.
    
    
11. Adequate shelf life and performance as a lead containing solder.
    The paste will last 3 month or longer with proper storage conditions.
    
    
12. Alloy should be low in cost.
    Much lower cost than Sn/Ag, Sn/Ag/Bi, Sn/Ag/Cu and other leading lead-free alloys.
    

The Sn/Zn/Al alloy meets all above criteria.

In terms of quality and reliability you can always rely on our products. This lead-free solder alloy is available in the form of sphere, solder paste and solder wire.