Tin Foil is a thin, ductile sheet of metallic tin (Sn), produced by rolling high-purity refined tin into extremely thin gauges. Historically used for food packaging, tin foil today is mainly applied in specialty electrical, chemical, laboratory, and restoration applications, as aluminum foil has replaced it for mass-market use.
Basic Identification
| Property | Value |
|---|---|
| Base Metal | Tin (Sn) |
| Allotrope | β-Tin (White Tin) |
| Typical Purity | ≥ 99.85% |
| Thickness Range | ~5 – 50 microns |
Chemical Composition
| Element | Content |
|---|---|
| Tin (Sn) | 99.85 – 99.99% |
| Lead (Pb) | ≤ 0.05% (often lead-free) |
| Antimony (Sb) | Trace |
| Bismuth (Bi) | Trace |
| Iron (Fe) | Trace |
| Oxygen | Trace (surface oxide only) |
Mechanical Properties
Tin foil is extremely soft, highly ductile, and easily deformable.
| Property | Typical Value |
|---|---|
| Tensile Strength | 14 – 25 MPa |
| Yield Strength | Very low |
| Elongation | > 40% |
| Hardness | ~5 – 10 HV |
| Formability | Excellent |
| Creep Resistance | Low |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.31 g/cm³ |
| Melting Point | 231.9 °C |
| Electrical Conductivity | ~15% IACS |
| Thermal Conductivity | ~66 W/m·K |
| Magnetic Behavior | Diamagnetic |
| Surface Appearance | Smooth, matte-silver |
Metallurgical Behavior
Tin foil cannot be heat treated for strengthening. Strengthening is limited to work hardening during rolling. Due to its low melting point, tin foil recrystallizes easily and loses strength rapidly at slightly elevated temperatures.
Corrosion & Chemical Behavior
✔ Excellent corrosion resistance in neutral and organic environments
✔ Forms a thin, stable SnO₂ passive layer
⚠ Limited resistance to strong acids, alkalis, and chloride-rich solutions
Manufacturing Process
Electrolytically refined tin is cast into slabs, hot rolled, cold rolled to micron-level thickness, annealed for stress relief, and slit or cut into final foil dimensions.
Available Forms
✔ Tin foil rolls
✔ Cut sheets
✔ Laminated foil (paper or polymer backed)
✔ Specialty coated foils
Applications
🧪 Laboratory and chemical shielding
🔌 Electrical contacts, capacitors, and EMI shielding (low-current)
🍬 Historical and specialty food & pharmaceutical wrapping
🏺 Decorative crafts and antique restoration
Advantages
✔ Non-toxic and chemically stable
✔ Extremely soft and conformable
✔ Excellent corrosion resistance
✔ Compatible with tin-based solders
✔ Fully recyclable
Limitations
❌ Very low mechanical strength
❌ Easily torn
❌ Poor heat resistance
❌ Higher cost compared to aluminum foil
Tin Foil vs Aluminum Foil
| Feature | Tin Foil | Aluminum Foil |
|---|---|---|
| Density | Higher | Lower |
| Strength | Lower | Higher |
| Corrosion Resistance | Better in neutral env. | Good |
| Cost | Higher | Lower |
| Modern Usage | Niche | Dominant |
Why Choose Tin Foil?
Tin foil is selected when purity, chemical stability, and non-toxicity are more important than strength or cost. It remains valuable in laboratory work, specialty electronics, chemical shielding, and heritage restoration.