Electrical and Thermal Conductivity of Pure Copper

Pure copper, often referred to as commercially pure copper or oxygen‑free high‑conductivity (OFHC) copper, is globally recognized as the benchmark material for electrical and thermal conductivity among all commonly used industrial metals. Its outstanding conductive performance has made it irreplaceable in power transmission, electronics, heat exchange, and many other high‑tech fields.

The standard measurement for conductivity is the International Annealed Copper Standard (IACS), where 100% IACS is defined as the conductivity of pure copper under specified conditions. Well‑processed pure copper typically achieves 97%–100% IACS, and high‑purity oxygen‑free copper can even exceed 100% IACS. This extremely high conductivity means that pure copper allows electric current to pass through with very low resistance, minimizing energy loss in the form of heat. Compared with other common metals, pure copper's conductivity is far higher than aluminum, steel, iron, and most alloys. Only silver has slightly better electrical conductivity, but silver is too expensive for large‑scale industrial applications. Therefore, pure copper is the most economical and practical choice for high‑efficiency electrical conduction. The high conductivity of pure copper mainly comes from its simple face‑centered cubic crystal structure and high purity. Impurities such as oxygen, phosphorus, iron, and lead will disrupt the crystal lattice and impede the movement of free electrons, significantly reducing conductivity. This explains why strictly controlled purity is critical in the production of conductive copper materials.

In terms of thermal conductivity, pure copper also performs exceptionally well. 

Its thermal conductivity is approximately 380–401 W/m·K at room temperature, making it one of the best metallic heat conductors. This property allows pure copper to quickly absorb, transfer, and dissipate heat. High thermal conductivity is essential in applications requiring rapid heat exchange or temperature control. For example, pure copper is widely used in heat exchangers, radiators, cooling pipes, engine components, and soldering materials. Unlike many alloys whose thermal conductivity drops sharply with increasing impurity content, pure copper maintains stable and efficient thermal transfer performance due to its high purity. Its excellent thermal conductivity matches its electrical conductivity very well, which is a rare advantage among metallic materials.

Although conductivity decreases slightly as temperature rises, pure copper still outperforms most alternative metals. After proper annealing treatment, pure copper can restore high conductivity even after cold working. This combination of high electrical conductivity, high thermal conductivity, good ductility, and processability gives pure copper a unique competitive advantage.

In summary, pure copper has excellent electrical conductivity close to 100% IACS and ultra‑high thermal conductivity of 380–401 W/m·K, making it the preferred material in applications requiring efficient conduction of electricity or heat.