The differences between oxygen-free copper, low-oxygen copper, and electrolytic copper are as follows:
I. purity: Oxygen-free copper has extremely high purity, typically with an oxygen content of less than 20ppm and minimal impurity content, with copper content reaching over 99.99%.
Low-oxygen copper: Its oxygen content is generally around 200 – 400ppm, and its purity is slightly lower than that of oxygen-free copper.
Electrolytic copper: It has a high purity, reaching 99.95% – 99.98%, but still contains a certain amount of oxygen and other impurities such as lead, bismuth, and antimony.
II. Production Process of Oxygen-Free Copper: It is typically produced using the up-drawing method or continuous casting and rolling process. During the production process, the oxygen content needs to be strictly controlled, and special melting equipment and processes are employed to ensure the purity and performance of the copper.
Low-oxygen copper: It is generally produced using continuous casting and rolling processes, where the control of oxygen content during production is relatively loose. The required performance requirements are achieved by regulating the oxygen content and additive usage during melting.
Electrolytic copper: Produced through electrolytic refining, where crude copper is used as the anode and pure copper as the cathode. It is electrolyzed in a copper sulfate electrolyte, allowing impurities in the crude copper to be removed during the electrolysis process, thereby obtaining high-purity electrolytic copper.
III. Performance Characteristics
1) Electrical Conductivity: Oxygen-free copper exhibits the best electrical conductivity, followed by low-oxygen copper, with electrolytic copper being relatively inferior. This is due to the presence of oxygen and other impurities, which increase electron scattering and lead to an increase in resistance.
2) Mechanical properties: Oxygen-free copper exhibits good ductility and toughness, and possesses a soft texture.
The mechanical properties of low-oxygen copper are similar to those of oxygen-free copper, but slightly inferior.
The mechanical properties of electrolytic copper vary depending on the type and content of impurities. Generally speaking, when the content of impurities is high, its strength may increase, but its toughness and ductility will decrease.
3) Corrosion resistance: Oxygen-free copper and low-oxygen copper exhibit good corrosion resistance due to their low oxygen content, making them less prone to oxidation reactions. However, electrolytic copper, which contains a certain amount of impurities, may have its corrosion resistance compromised in certain specific environments.