Detailed Explanation of the Differences and Characteristics between Purple Copper and Oxygen-Free Copper

Red Copper and Oxygen-Free Copper: A Comparison of Two Kinds of Copper

Red copper, often referred to as red brass, gets its name because it appears in a purplish red color. Although it is often mistaken for pure copper, in reality, the theoretical copper content of pure copper strictly speaking should be close to 100%. Red copper, as a relatively pure form of copper, typically has a copper content ranging from 99.5% to 99.99%. This material not only has excellent electrical and thermal conductivity but also exhibits excellent plasticity, making it suitable for hot pressing and cold pressing processing. Therefore, red copper plays a crucial role in manufacturing products such as wires, cables, brushes for electrical purposes, and copper for electrochemical etching, which require good electrical conductivity.

The main grades of copper include T1, T2 and T3. Among them, T1 copper has a copper content exceeding 99.95% and the total impurity content does not exceed 0.05%; T2 copper has a copper content above 99.90%, with the impurity content not exceeding 0.1%; while T3 copper has a copper content of no less than 99.7% and the impurity content does not exceed 0.3%. In addition, there are international standard grades such as C11000, where the total content of copper and silver needs to reach or exceed 99.90%.

On the other hand, oxygen-free copper, although its name does not contain oxygen, actually still contains trace amounts of oxygen and some impurities, but the content is extremely low. According to the standard, its oxygen content does not exceed 0.003%, the total impurity content does not exceed 0.05%, and the purity of copper is over 99.95%. Due to its extremely low oxygen content, oxygen-free copper exhibits outstanding electrical conductivity, thermal conductivity, corrosion resistance and processing performance. In the manufacturing of parts for electrical vacuum instruments and meters, such as busbars, conductive strips, waveguides, etc., oxygen-free copper plays a crucial role. Its excellent processing performance also makes it suitable for fine processing. It can be said that oxygen-free copper is a special type of copper.

The main grades of non-oxidized copper include TU1, TU2, C10100 and C10200. Among them, TU1 non-oxidized copper, with a purity of up to 99.97% and excellent comprehensive performance, plays an indispensable role in the fields of electronics and electrical engineering.

TU2 non-oxidized copper has a copper content greater than 99.95%, with the oxygen content strictly controlled within 0.003% and the total impurity content not exceeding 0.05%. This high-purity copper material not only has excellent electrical conductivity but also exhibits outstanding cold and hot processing performance and welding performance. Its forgeability is excellent, enabling TU2 non-oxidized copper to play an indispensable role in the production and processing of components and equipment where the requirements for conductivity and extensibility are extremely strict.

C10100 oxygen-free copper typically has a copper content of over 99.99%, with an oxygen content lower than 0.001%, ensuring the high purity of the material. This high-purity oxygen-free copper not only has excellent electrical and thermal conductivity, but also possesses corrosion resistance, low porosity, and outstanding forming processing performance. In various industries such as electronics, electrical appliances, aerospace, and automotive manufacturing, C10100 has demonstrated broad application prospects.

C10200 oxygen-free copper has a copper content of no less than 99.95%, with the total impurities controlled within 0.05%, meeting the strict requirements of electric vacuum devices and instruments, and meters and other fields.

In appearance, purple copper usually appears in a purplish red color, earning its name for its vivid and lustrous characteristics. However, due to its tendency to oxidize in the air, a layer of dark red or dark black copper oxide film may gradually form on the surface of purple copper. Nevertheless, the base color of purple copper remains clearly visible. In contrast, non-oxygenated copper presents a purer copper color, close to silver white or pale yellow. Its extremely low oxygen content makes it relatively stable in the air, with an oxidation rate much lower than that of purple copper, so the surface color changes less and it can maintain its bright metallic luster for a long time.

Furthermore, in terms of surface finish, due to its relatively soft nature, copper alloy is prone to scratches and abrasions during processing and usage, resulting in damage to the surface finish. In contrast, oxygen-free copper, with its high purity and uniform composition, is easier to achieve high-quality surface quality during processing, presenting a smooth and fine appearance characteristic.

Of course, although appearance can be used to distinguish copper alloy from oxygen-free copper to some extent, this method is not absolutely accurate. In practical applications, such as for more accurate judgment of the differences between the two materials, other methods such as chemical analysis and physical performance testing need to be combined.

Copper alloy, with its relatively lower strength and hardness and softer texture, is prone to deformation during processing and usage. Especially when making thin-walled parts, this characteristic of copper alloy needs to be specially considered to prevent deformation or damage. However, oxygen-free copper has undergone special treatment and has higher strength and hardness, which makes it perform well in situations that require pressure and wear resistance. For example, in the aerospace field, the high strength and hardness of oxygen-free copper fully meet the strict requirements of aircraft materials.

Not only that, but oxygen-free copper also outperforms red copper in terms of corrosion resistance, being able to better withstand the erosion of various corrosive environments.

In terms of resistivity, although red copper has good electrical conductivity, ranking second only to silver, it is slightly inferior to oxygen-free copper in terms of electrical conductivity. Especially in the electrical field, although red copper wires can effectively transmit current, in environments with high requirements for conductivity, their performance may not fully meet the needs. In contrast, the resistivity of oxygen-free copper is lower, and its conductivity is over 100% IACS, giving it significant advantages in the fields of electronics and electrical engineering. For example, in high-fidelity audio cables, oxygen-free copper can ensure the high-quality transmission of audio signals and effectively reduce signal loss.

At the same time, the thermal conductivity of oxygen-free copper is also slightly higher than that of red copper, which further enhances its application advantages in high-end electronic devices. Its high thermal conductivity helps with heat dissipation, thus ensuring the stable operation of the equipment.

In terms of application and price, red copper plays a significant role in various fields such as electrical, electronic and industrial due to its wide applicability. On the other hand, oxygen-free copper, with its excellent conductivity and signal transmission capabilities, as well as its applications in high-end electronic products and aerospace and other fields, has a relatively higher price.

Oxygen-free copper indeed demonstrates superiority over ordinary red copper in certain performance aspects, but this does not mean that oxygen-free copper is inherently more advanced than red copper. The choice of which copper material to use actually depends on specific application scenarios and requirements. In various applications, both red copper and oxygen-free copper showcase their unique advantages.

Broadly speaking, oxygen-free copper can be regarded as a type of copper material within the larger category of red copper that possesses specific properties and specialized uses. Therefore, the production process of oxygen-free copper is more complex compared to red copper, and its production cost is accordingly higher. As a result, in the market, the price of oxygen-free copper is usually several thousand yuan per ton higher than that of red copper.