Sn43Bi57 T4 solder powder

The Sn43Bi57 T4 solder powder is a lead-free tin-bismuth alloy with a melting point of approx. 139 °C. With 43 % Tin and 57 % Bismuth it is tailored to the requirements temperature-sensitive electronics customised. The T4 grit (20-38 µm) ensures even finer paste deposition than the T3 version and is ideal for fine-pitch structures, LEDs and high-density assemblies.

Properties and advantages

• Low melting point (~139 °C): Ideal for components that cannot tolerate high temperatures.
• Fine T4 grit: Supports high-resolution stencil printing processes and enables precise paste placement.
• Increased tin content: Ensures better wetting and mechanical stability compared to Sn42Bi58.
• Lead-free & RoHS compliant: Sustainable choice for modern electronics production.
• Reliable solder joints: Homogeneous, durable connections with high process reliability.

Areas of application

Fine-Pitch & LEDs

Thanks to the fine T4 grit Sn43Bi57 is particularly suitable for LEDs, displays and fine-pitch components where precise solder joints are crucial. It reduces bridging and improves quality in high-density circuits.

SMT & reflow processes

In the Semiconductor Technology & Electronics the powder is used in stencil printing and reflow soldering where precise wetting and consistent melting properties are required.

Hard & soft soldering

Also in the area of Hard & soft soldering Sn43Bi57 T4 convinces with stable flow properties and a clearly defined melting point.

Automotive industry & electrical engineering

In the Automotive industry and Electrical engineering the alloy is used when assemblies need to be thermally protected, but at the same time durable, reliable solder joints are required.

Technical properties

• Composition: Sn 43 %, Bi 57 %
• Melting point: approx. 139 °C
• Grain size: T4 (20-38 µm)
• Particle morphology: spherical for stable paste rheology
• Purity: High quality, low oxidation tendency

Sustainability & regulation

As Lead-free solder Sn43Bi57 T4 fulfils the RoHS requirements and is an environmentally friendly alternative to leaded solders. The low melting point also saves energy in the soldering process.

Conclusion

Sn43Bi57 T4 solder powder is the perfect solution for Fine-pitch, LED and SMT applications. With its fine grain, low melting point and high reliability, it offers maximum precision for modern electronics. You can find further information on fields of application in the areas Semiconductor Technology & Electronics and Hard & soft soldering.