Due to challenges inherent in the copper-refining process, all high-conductivity coppers contain some amount of oxygen.

However, many applications require high-purity copper alloys that include little to no oxygen content. These alloys are referred to as oxygen-free coppers (OFCs). At Sequoia Brass and Copper, we use an electrically charged solution of copper sulfate and sulfuric acid to produce OFCs and oxygen-free high–thermal conductivity coppers (OFHCs). This process reduces copper-oxygen content to 0.001% or less, resulting in >99.99% pure copper alloys.

Many applications use OFCs and OFHCs, particularly in the electrical and electronics industry. OFCs and OFHCs form integral parts of semiconductors, superconductors, particle accelerators, and sputtering processes.

Properties of OFCs and OFHCs

  • Electrical Conductivity: Electronics manufacturers prize OFCs for their superior electrical conductivity. The significantly low oxygen content of this copper grade rates a minimum of 101.5% or more on the IACS (International Annealed Copper Standard) conductivity rating.

    Enhanced conductivity allows OFCs to operate at lower temperatures when subjected to electric currents. This characteristic protects electrical equipment by reducing the risk of overheating caused by insufficient or inefficient power transfer.

  • Thermal Conductivity: As their name suggests, OFHCs possess high heat conductivity properties. This heat conductivity makes OFHCs ideal materials for electron beam welding as copper can absorb considerable amounts of heat produced at the weld zone.
  • Durability and Impact Resistance: OFCs are harder and resist impact loads better than comparable copper alloys. OFCs can achieve a Vickers Hardness (Hv) of up to 115, whereas the Hv of conventional copper alloys may be as low as 40.
  • Corrosion Resistance: The high purity (99.99%) and reduced oxygen content of OFCs provide superior corrosion resistance to other copper alloys. This resistance primarily stems from OFCs’ single-phase structure and lack of impurities, which promote the formation of electrochemical cells that lead to galvanic corrosion.

Sequoia Brass and Copper supplies a broad range of C10100 oxygen-free (OFE-OFHC) copper alloy rods, bars, tubes, sheets, strips, and plates.

OFC and OFHC applications

The chemical purity and stability of OFCs and OFHCs make them ideal for plasma deposition (sputtering) as well as for manufacturing semiconductors and other sensitive electrical devices. Their low volatility under vacuum conditions also allows these copper alloys to assist with conductivity applications such as:

  • Microwave tubes
  • Vacuum capacitors
  • Vacuum interrupters
  • Vacuum seals
  • High-temperature electrode welding

Building Pure Copper Alloys with Us

At Sequoia Brass and Copper, we provide only the highest-quality OFC and OFHC products. Our quality management systems ensure that all materials undergo stringent tagging and heat-numbering procedures, ensuring top-grade purity. Mill test certificates and refinery reports help ensure that alloy chemical compositions and strength/physical properties meet ASTM standards.

Our commitment to continuous process improvement shows through in the quality of our products, their speed of delivery, and the overall service we provide. If you would like to learn more about our OFC and OFHC products and how to use them in your application, contact our sales team today!