Balver Zinn Lead free SN100C
Balver Zinn solder SN100C is a nickel-stabilized tin copper eutectic, with a small amount of germanium added to reduce oxidation of the solder. SN100C is the trade name for SnCu0,7Ni, the lead-free* solder for wave soldering. Balver Zinn solder SN100C generates bright and shiny solder joints, comparable with lead-containing solders.
In 2005, NASA tests found Balver Zinn solder SN100C to be the most reliable soft solder for wave soldering. More detailed results are available in Balver Zinn technical information: “Reliability of SN100C.” Compared to conventional SnCu solders, SN100C causes substantially less copper dissolution, thus minimizing the risk of unacceptable reduction of electric and thermal conductivity.
The lower copper dissolution makes it easier to maintain the composition of the solder bath within specification and reduces the need to scrap material because of contamination. The soldering results are better than with standard lead-free* solders – especially the reduced tendency to bridging.
According to the independent ELFNET study, Balver Zinn solder SN100C is the most used wave solder in Europe. Balver Zinn solder SN100C is preferred for the higher process temperatures of selective soldering.
*Balver Zinn solder SN100C does not contain hazardous substances beyond the limits prescribed by EU Directive 2002/95/EG (“RoHS”)
General Process Information
- At a copper content of more than 0.85%, significantly more soldering defects occur (bridging). To avoid these, Balver Zinn offers complimentary solder bath analyses. When soldering any printed circuit board - except those with a nickel/gold finish – SN100Ce SnNi should be used for bath top-up to ensure constant process conditions.
- The copper tin crystals precipitating at a copper content of more than 0.9% (intermetallic joints), have a grinding effect and, due to the low density of the solder, accumulate on the bottom of the solder bath. They cannot be removed from the solder surface by a perforated spoon.
- Due to its special stabilization, SN100C affects pots and pumps far less than tin silver copper solders. In special cases, SN100C can be used in soldering machines with plain stainless steel pots.
- In order to reduce solder losses as dross, nitrogen protection is recommended.
- Balver Zinn conducts complimentary, regular solder bath analyses to determine the customer-specific bath top-up schedule and avoid problems caused by a too high level of impurities.
Process Conditions for Wave Soldering
- Solder bath temperature 260-270°C. Please note that it is not the solder temperature but the temperature measured on the components that determines the thermal stress to which the component is subjected!
- Before entering the wave, the printed circuit boards should be about 10 – 20°C warmer than for tin-lead applications (Sn63Pb37). 110-135°C, measured on the top surface, are usual conditions. Here, the old rule applies: “Do not try to use the wave for preheating.”
- The contact time in the wave must be increased due to the slower wetting in comparison to tin lead (Sn63Pb37).