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EGaIn Alloy
EGaIn: The Eutectic Gallium-Indium Alloy
Binary liquid metal for stretchable electronics, soft robotics, and advanced applications.
EGaIn (Eutectic Gallium-Indium) is a room-temperature liquid metal alloy composed of gallium and indium that remains fluid at standard conditions. This binary eutectic alloy offers excellent electrical conductivity while being safer than mercury.
| Property | Value | Notes / Significance |
|---|---|---|
| Composition | Ga (~75.5 wt%), In (~24.5 wt%) | Binary eutectic alloy |
| Melting Point | ~15.7°C | Higher than Galinstan but still below room temperature While higher than Galinstan, it still remains liquid in most indoor environments |
| Density | ~6.25 g/cm³ | About 6.25× that of water Slightly less dense than Galinstan |
| Viscosity | ~1.7-2.0 mPa·s | Similar to water (~1.0 mPa·s) Flows easily in microfluidic channels |
| Surface Tension | ~0.624 N/m | Forms oxide skin in air Higher than Galinstan, affects how it behaves in microfluidic systems |
| Electrical Conductivity | ~3.4 × 10^6 S/m | Excellent conductor Essential for its applications in flexible electronics |
| Thermal Conductivity | ~26.6 W/(m·K) | Good heat transfer Useful in thermal management applications |
Conceptual 3D Model
Conceptual 3D representation of EGaIn's metallic mixture (not an actual crystal structure).
Applications
EGaIn's unique properties make it ideal for numerous innovative applications:
Stretchable Electronics
Creates deformable electrical connections that maintain conductivity under strain.
Soft Robotics
Enables flexible, deformable components in advanced robotics systems.
Pressure Sensors
Creates microfluidic sensors that detect pressure changes with high sensitivity.
Thermal Interface Materials
Enhances heat transfer between components in electronics.
Element Breakdown
Symbol: Ga
Atomic Number: 31
Key Role in EGaIn: Major constituent (~75.5%) that lowers the melting point significantly.
Fun Fact: Pure gallium can melt in your hand (m.p. ~29.8°C)
Symbol: In
Atomic Number: 49
Key Role in EGaIn: Forms the eutectic mixture with gallium (~24.5%), enabling the lower melting point.
Industrial Use: Widely used in transparent electrodes (ITO) and solders.
Temperature vs. Viscosity
Approximate viscosity trend with increasing temperature (indicative values).
Safety & Handling
- General Safety: EGaIn is considered non-toxic, though standard lab practices should be followed.
- Material Compatibility: Avoid contact with aluminum surfaces as gallium can amalgamate with and weaken aluminum structures.
- Oxidation: Forms a thin oxide layer when exposed to air, which can be removed with mild acids if necessary.
- Storage: Keep in sealed, inert containers to minimize oxidation.
Environmental Impact
As a mercury-free alternative, EGaIn represents an environmentally safer option for applications that historically used mercury. Gallium is primarily obtained as a byproduct of aluminum production, while indium is typically recovered during zinc ore processing.
Neither element poses significant environmental hazards when handled properly, though responsible disposal practices should always be followed.