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InBiSn Alloy
Indium-Bismuth-Tin (InBiSn) Alloy
An ultra-low temperature solder alloy combining indium, bismuth, and tin for advanced, delicate electronic applications.
The InBiSn alloy is designed for applications where an ultra-low melting point and minimal thermal stress are essential. Typically composed of approximately 20% indium, 50% bismuth, and 30% tin, it exhibits a melting point of around 70°C, moderate electrical resistivity, and balanced thermal conductivity. Its unique composition makes it ideal for cryogenic sensors, flexible electronics, and advanced packaging.
| Property | Value | Notes |
|---|---|---|
| Composition | In ~20%, Bi ~50%, Sn ~30% | Ternary eutectic ratio for ultra-low melting performance |
| Melting Point | ~70°C | Enables soldering on temperature-sensitive substrates |
| Electrical Resistivity | ~35 µΩ·cm | Balanced conductivity for precision applications |
| Thermal Conductivity | ~30 W/m·K | Efficient heat dissipation in compact assemblies |
| Mechanical Strength | ~5 MPa | Lower strength reflecting high ductility |
Conceptual 3D Microstructure
A simplified 3D model representing alternating eutectic layers of indium, bismuth, and tin.
Applications
Ultra-Low Temp Soldering
Minimizes thermal stress on delicate substrates.
Flexible Electronics
Ideal for bendable devices and wearable applications.
Precision Interconnects
Ensures reliable connections in high-performance circuits.
Advanced Packaging
Supports miniaturization and high-density assembly.
Element Breakdown
Symbol: In
Atomic Number: 49
Key Role in InBiSn: Provides ductility and lowers the melting point.
Fun Fact: Indium is essential for forming reliable, low-temp solder joints.
Symbol: Bi
Atomic Number: 83
Key Role in InBiSn: Increases fluidity and further reduces the melting point.
Fun Fact: Bismuth adds unique low-temperature properties to the alloy.
Symbol: Sn
Atomic Number: 50
Key Role in InBiSn: Enhances wettability and joint reliability.
Fun Fact: Tin has been used in soldering for centuries due to its excellent bonding characteristics.
Performance Comparison: Melting Point
Comparison of melting points among popular solder alloys. The InBiSn alloy's ~70°C melting point is ideal for ultra-low temperature processes.
Advantages Over Traditional Solders
| Property | 63Pb/37Sn (Lead-Based) | SAC (Lead-Free) | InPb | InBiSn Alloy |
|---|---|---|---|---|
| Melting Point (°C) | 183 | 217 | 125 | 70 |
| Electrical Resistivity (µΩ·cm) | 20 | 15 | 30 | 35 |
| Thermal Conductivity (W/m·K) | 35 | 60 | 40 | 30 |
| Mechanical Strength (MPa) | 26 | 40 | 6 | 5 |
Manufacturing & Production
The InBiSn alloy is produced by melting high-purity indium, bismuth, and tin under a controlled atmosphere to achieve the eutectic composition. Its ultra-low melting point reduces energy usage and minimizes thermal stress during soldering, making it ideal for precision, low-temp applications.
Safety & Handling
- Molten InBiSn must be handled with proper protective gear to avoid burns.
- Work in well-ventilated areas and follow proper recycling protocols due to the scarcity of indium.
- Adhere to environmental guidelines when handling bismuth-containing materials.