What Is OFHC C10100 Copper
OFHC stands for oxygen-free high conductivity. C10100 is produced by the direct conversion of selected refined cathodes under carefully controlled conditions that prevent contamination of the pure metal during processing. The result is a copper grade with a minimum copper content of 99.99 percent and an oxygen content held at a virtually undetectable level. Because extraneous elements are so few, the inherent properties of elemental copper, especially electrical and thermal conductivity, are preserved to a very high degree.
Chemical Composition and Purity
C10100 is the highest-purity wrought copper grade in the UNS system. Copper plus silver is 99.99 percent minimum, with oxygen limited to 5 ppm and total impurities held below 100 ppm. This purity level is what distinguishes OFHC C10100 from ETP copper such as C11000, which contains oxygen and can suffer hydrogen embrittlement when heated in reducing atmospheres.
Physical and Mechanical Properties
C10100 combines the highest conductivity available in a commercial copper grade with good strength in cold-worked tempers. The table below lists typical values.
| Property | Typical Value |
|---|---|
| Density | 8.94 g/cm3 (0.323 lb/in3) |
| Electrical resistivity at 20 C | 10.3 microhm-cm |
| Electrical conductivity | 101 percent IACS |
| Melting point | 1083 C (1981 F) |
| Modulus of elasticity in tension | 117 GPa (17000 ksi) |
Mechanical values depend on temper. In the soft annealed condition, tensile strength is about 195 MPa minimum with elongation of 30 percent or more, while quarter-hard, half-hard, full-hard, and extra-hard tempers progressively raise strength to above 350 MPa.
Electronics and Electrical Engineering Applications
OFHC C10100 is specified where low-loss signal transmission and stable performance under vacuum or high-frequency conditions are required.
High-frequency conductors, waveguides, and transformer windings.
Vacuum electronic devices and glass-to-metal seals, where low gas release is essential.
Sputtering targets and support structures in semiconductor equipment.
Superconducting magnet components that rely on high-purity, stable material.
Thermal Management and Vacuum Technology
The high thermal conductivity of C10100 makes it effective for heat sinks, heat pipes, and heat-spreading components. In high-energy physics and scientific research, oxygen-free copper is preferred for vacuum chambers because it releases very little gas in a vacuum environment, helping to maintain stable operating conditions.
Fabrication and Joining
C10100 has excellent hot and cold formability. It can be drawn, rolled, bent, and deep drawn without difficulty, and it joins well by brazing, soldering, and welding when appropriate shielding is used. Because it is oxygen-free, it is not subject to hydrogen embrittlement, which makes it a reliable choice for assemblies exposed to high-temperature brazing atmospheres.
Frequently Asked Questions
Q: What does OFHC mean?
A: OFHC means oxygen-free high conductivity, a production method that delivers 99.99 percent pure copper with minimal oxygen.
Q: How does C10100 differ from C10200?
A: Both are oxygen-free grades. C10100 has a higher guaranteed purity of 99.99 percent copper, while C10200 is specified at 99.95 percent minimum.
Q: Why is C10100 used in vacuum devices?
A: Its extremely low oxygen and impurity content minimizes outgassing under vacuum and high temperature.
Q: Is C10100 resistant to hydrogen embrittlement?
A: Yes. With no cuprous oxide in the structure, C10100 does not suffer hydrogen embrittlement in reducing atmospheres.
Q: What standards cover C10100 tubing?
A>Seamless tube is supplied to ASTM B75 and B68, with rod and bar to ASTM B187 and plate and sheet to ASTM B152.
