Oxygen-Free Copper (OFC) is a high-purity copper refined and processed in a strictly oxygen-free environment to achieve extremely low oxygen content (≤ 0.001%).
The absence of copper oxides results in exceptionally high electrical conductivity, superior ductility, excellent thermal performance, and outstanding resistance to hydrogen embrittlement.
Common international grades include C10100 (OFHC – Oxygen-Free High Conductivity) and C10200 (OFC).
Typical Chemical Composition
| Element | Typical % |
|---|---|
| Copper (Cu) | ≥ 99.99 |
| Oxygen (O) | ≤ 0.001 |
| Other impurities | ≤ 0.01 (total) |
Metallurgical Insight:
The near-absence of oxygen prevents Cu₂O formation,
which is critical for applications in vacuum,
cryogenic, and hydrogen environments.
Physical Properties
| Property | Typical Value |
|---|---|
| Density | 8.96 g/cm³ |
| Melting Point | 1083 – 1085 °C |
| Electrical Conductivity | 100 – 101% IACS |
| Thermal Conductivity | 390 – 400 W/m·K |
| Coefficient of Thermal Expansion | 16.5 × 10⁻⁶ /°C |
| Magnetic Behavior | Non-magnetic |
| Corrosion Resistance | Excellent |
Key Note:
Mechanical properties are similar to ETP copper,
but ductility and reliability at high temperatures
are significantly superior.
Strengthening & Metallurgical Behavior
Crystal Structure:
Single-phase FCC copper
No phase transformation
Strengthening Mechanisms:
Cold working (drawing, rolling)
❌ No precipitation or age hardening
Heat Treatment:
Annealing (200 – 600 °C) restores ductility
Excellent recrystallization behavior
No hydrogen embrittlement during heating
Refining & Processing Properties
Electrolytically refined to 99.99% purity, then melted and cast in oxygen-free or vacuum-controlled atmospheres. Unlike DHP copper, deoxidizers are not required.
✔ Excellent hot and cold workability
✔ Outstanding weldability and brazability
✔ Superior vacuum brazing performance
✔ Very low outgassing
✔ Fully recyclable without property degradation
Processing Advantage:
OFC is the preferred copper for vacuum furnaces
and hydrogen atmospheres.
Available Forms
Rods and bars
Sheets and plates
Strips and coils
Wires (solid and stranded)
Tubes and pipes
Foils
Busbars
Precision forgings
Sizes range from ultra-thin foils to large cross-section conductors.
Key Characteristics
✔ Extremely high electrical conductivity
✔ Excellent thermal conductivity
✔ No hydrogen embrittlement
✔ Superior ductility and toughness
✔ Low outgassing (vacuum compatible)
✔ High purity and chemical stability
✔ Non-magnetic and antimicrobial
Applications
Electrical & Electronics
High-end power cables, busbars,
semiconductor equipment,
RF and microwave components
Vacuum & Cryogenic
Vacuum chambers,
particle accelerators,
cryogenic pipelines,
fusion facilities
Aerospace & Defense
Satellite components,
avionics conductors,
radar and communication systems
Energy & Medical
MRI systems,
particle beam equipment,
high-purity heat exchangers
Audio & Precision Systems
High-end audio cables,
precision signal transmission
Advantages
✔ Higher purity than ETP copper
✔ Superior reliability at high temperatures
✔ Safe for hydrogen and vacuum environments
✔ Longer service life
✔ Minimal electrical losses
✔ High consistency and performance stability
Why Choose Oxygen-Free Copper?
OFC is selected when applications demand maximum electrical and thermal conductivity, operation in vacuum or hydrogen atmospheres, extreme reliability and purity, and precision electrical performance.
Industry Rule:
When failure is not an option and purity matters,
Oxygen-Free Copper is the gold standard.