Copper 101, also known as C10100 or Oxygen-Free Electronic (OFE) Copper, stands out as one of the purest commercial forms of copper available, with a minimum 99.99% purity and virtually no oxygen content. In this guide, we’ll explore everything you need to know about Copper 101: from its material properties, machinability, and yield strength to its common applications and differences between copper c101 vs c110 in terms of conductivity and cost.
What is Copper Alloy 101?
101 copper contains a minimum of 99.99% pure copper and is known for its excellent electrical and thermal conductivity, making it ideal for electrical wiring, busbars, and other applications where efficient conductivity is critical. This grade is commonly used in electronics, power generation, and transmission industries due to its high ductility, corrosion resistance, and ability to be easily fabricated or soldered. The “101” designation comes from the Unified Numbering System (UNS) for metals and alloys, where it’s listed as C11000 or UNS C10100.
Copper C101 Equivalent
If you’re sourcing or specifying C101 copper internationally, look for Cu-OF (Oxygen-Free Copper) or CW009A in Europe. While C1020 in Japan is close, it has slightly lower purity and higher oxygen content, so for critical applications, C10100 or CW009A is preferred.
| Standard/System | Equivalent Grade | Notes |
|---|---|---|
| UNS (USA) | C10100 | Official UNS designation |
| ASTM | ASTM B170 (C10100) | Specification for high-conductivity copper |
| EU / EN (Europe) | Cu-OF / CW009A | EN 13601 or EN 13599 |
| BS (UK) | C101 / Cu-OF | British Standard equivalent |
| DIN (Germany) | Cu-OF | Oxygen-free copper designation |
| JIS (Japan) | C1020 | Closest Japanese match; slightly lower purity |
| ISO | Cu-OF | Matches international oxygen-free standard |
Copper C101 Chemical Composition
| Element | Percentage |
|---|---|
| Copper (Cu) | ≥99.99% |
| Oxygen (O) | ≤0.0005% |
| Silver (Ag) | 0.015% max |
| Phosphorus (P) | 0.005% max |
| Other Elements | Trace amounts, typically less than 0.001% each of elements such as lead, arsenic, bismuth, etc. |
Copper C101 Common Applications
-Electrical Conductors & Busbars: Used in high-efficiency electrical systems where minimal resistance and power loss are essential.
-Vacuum Tubes & Electron Devices: Ideal for vacuum environments due to its lack of oxygen, preventing hydrogen embrittlement.
-Heat Exchangers & Heat Sinks: High thermal conductivity makes it perfect for managing heat in electronics and cooling systems.
-Semiconductor Manufacturing Equipment: Used in cleanroom-grade machinery where contamination from oxygen must be avoided.
-Cryogenic Applications: Performs well at extremely low temperatures, often used in superconducting systems.
-Aerospace & Defense Components: Applied in systems where reliable electrical and thermal performance under stress is required.
-RF & Microwave Systems: Excellent conductivity and purity make it suitable for minimizing signal loss at high frequencies.
Copper Alloy 101 Properties
Copper 101 is often chosen for high-performance or precision applications where typical copper grades like C110 may fall short due to oxygen content or slightly lower conductivity.
Key Advantages
Ultra-high purity
Outstanding electrical and thermal conductivity
Ideal for vacuum, cryogenic, and high-frequency electronic applications
Physical Properties
Density: 8.94 g/cm³
Melting Point: 1,083°C (1,981°F)
Thermal Conductivity: 391–400 W/m·K (at 20°C)
Electrical Conductivity: Up to 101% IACS (International Annealed Copper Standard)
Specific Heat: ~0.385 J/g·K
Coefficient of Thermal Expansion: ~16.5 µm/m·°C
Mechanical Properties (Annealed Condition)
Tensile Strength: 200–250 MPa
Yield Strength: 70–100 MPa
Elongation: ~45%
Hardness: ~50–60 Brinell (HB)
Corrosion Resistance & Fabrication
Excellent resistance to corrosion in most environments
Excellent weldability and solderability
Easily fabricated, machined, and cold-worked
Copper 101 Thermal Conductivity
Copper 101 (C10100), also known as Oxygen-Free Electronic (OFE) Copper, has exceptionally high thermal conductivity, making it one of the most efficient materials for heat transfer.
Typical Value: 391 to 400 W/m·K at room temperature (20°C)
Purity: 99.99%+
Oxygen Content: ≤ 0.0005% (essentially oxygen-free)
Copper 101 Machinability
C101 copper has poor to fair machinability, primarily due to its high purity and softness. Its oxygen-free structure makes it ideal for electrical and thermal applications, but not great for machining, especially when compared to alloys that contain small amounts of sulfur or other elements added specifically to improve machinability.
Copper 101 Machinability Overview:
Machinability Rating: ~20% (relative to free-machining brass = 100%)
Workability: Excellent for cold and hot working (forming, bending, etc.)
Soldering and Brazing: Excellent
Welding: Not recommended (can be done with caution, but may lose oxygen-free quality)
Tips for Machining Copper 101:
Use sharp tools with positive rake angles
Maintain good chip control (chips can be long and stringy)
Use plenty of lubrication to reduce tool wear and heat buildup
Opt for slow to moderate cutting speeds and light feeds
Copper 101 Yield Strength
The yield strength of Copper 101 (C10100, Oxygen-Free Electronic Copper) depends on its temper (how it’s been processed), but in its common annealed (soft) condition, the values are:
Annealed (Soft, O Temper):
~33 to 69 MPa (megapascals)
(~4.8 to 10 ksi)
Harder tempers (e.g., H02, H04):
Yield strength can increase to 100–250 MPa depending on the degree of cold working.
Yield strength is the stress at which the material begins to deform plastically. Annealed Copper 101 is very soft and ductile, which makes it easy to form and shape, but not ideal for structural load-bearing applications. For applications requiring higher strength, cold working or using an alloyed copper (like C110 or C145) may be preferred. So, if you’re using Copper 101 for high-conductivity electrical or thermal components and need it to flex or bend easily, the low yield strength is actually a benefit.
Copper Alloy C101 Purity
The purity of 101 copper (C10100) is 99.99% or higher. It is classified as Oxygen-Free Electronic (OFE) copper, meaning it contains less than 0.0005% oxygen and extremely low levels of impurities. This ultra-high purity is what gives Copper 101 its exceptional electrical and thermal conductivity, making it ideal for critical applications in electronics, aerospace, cryogenics, and vacuum systems.
Copper 101 Density
The density of Copper c101 (C10100)—also known as Oxygen-Free Electronic (OFE) Copper—is:
8.94 g/cm³ (grams per cubic centimeter)
8940 kg/m³ (kilograms per cubic meter)
0.324 lb/in³ (pounds per cubic inch)
This is the same as pure copper, since Copper 101 is ≥99.99% pure. Its high density, combined with excellent electrical and thermal properties, makes it ideal for precision electrical and thermal applications.
Copper 101 vs 110 Thermal Conducity: Which is Better
Copper 101 and Copper 110 are both high-conductivity grades of copper, but they differ slightly in purity and therefore thermal conductivity:
Copper 101 (C10100): This is Oxygen-Free Electronic (OFE) copper with a minimum purity of 99.99%. It has excellent thermal conductivity, typically around 391–400 W/m·K at 20°C. Its extremely low oxygen content makes it ideal for high-vacuum or high-temperature environments where hydrogen embrittlement must be avoided.
Copper 110 (C11000): Known as Electrolytic Tough Pitch (ETP) copper, it has a slightly lower purity of about 99.90% and contains a small amount of oxygen (~0.02–0.04%). Its thermal conductivity is slightly lower than 101, usually around 385–390 W/m·K at 20°C.
Copper 101 vs 110 Electrical Conductivity: Which Is Better
When comparing Copper 101 vs Copper 110 in terms of electrical conductivity, Copper 101 is better, but only slightly:
Copper 101 (C10100) – Oxygen-Free Electronic (OFE) Copper
Purity: 99.99%+
Electrical Conductivity: Up to 101% IACS (International Annealed Copper Standard)
Advantage: Because it’s oxygen-free, it’s ideal for applications where even trace oxygen could cause problems—like in vacuum tubes, semiconductors, or high-frequency electronics.
Copper 110 (C11000) – Electrolytic Tough Pitch (ETP) Copper
Purity: ~99.90%
Electrical Conductivity: Around 100% IACS
Advantage: More affordable and widely used in general-purpose electrical applications like wiring, motors, and busbars.
Copper 101 has slightly better electrical conductivity due to its higher purity and lack of oxygen, but Copper 110 is more commonly used because it’s cheaper and still highly conductive. If you’re working on ultra-sensitive or high-performance electronic systems, go with Copper 101. For general electrical use, Copper 110 is more than sufficient.
Copper C110 vs C101, What’s the Difference?
Copper 110 (C11000) and Copper 101 (C10100) are both high-conductivity pure coppers, but they differ slightly in purity, oxygen content, conductivity, and applications.
- Copper 110 (ETP – Electrolytic Tough Pitch) contains ~99.90% copper with a small amount of oxygen (~0.02–0.04%). It offers excellent electrical conductivity (~100% IACS), is cost-effective, and is widely used for electrical wiring, busbars, and plumbing.
- Copper 101 (OFE – Oxygen-Free Electronic) is even purer, with ≥99.99% copper and virtually no oxygen. It provides slightly better conductivity (~101% IACS), is more resistant to embrittlement in hydrogen-rich or high-vacuum environments, and is used in aerospace, electronics, and high-frequency systems.
| Property | Copper 110 (C11000) | Copper 101 (C10100) |
|---|---|---|
| Purity | ~99.90% | ≥99.99% |
| Oxygen Content | ~0.02–0.04% | ≤0.0005% (oxygen-free) |
| Electrical Conductivity | ~100% IACS | ~101% IACS |
| Thermal Conductivity | ~385–390 W/m·K | ~391–400 W/m·K |
| Density | 8.94 g/cm³ | 8.94 g/cm³ |
| Yield Strength (Annealed) | ~69 MPa | ~33–69 MPa |
| Machinability | Fair | Poor to Fair |
| Weldability | Good | Not recommended (can lose OFE) |
| Applications | Wiring, busbars, plumbing | Aerospace, electronics, cryogenics |
| Cost | Lower | Higher |