Conductivity is the fundamental characteristic determining the efficiency of electrical current transmission in metals. The measure of the conductivity of a metal material is its electrical resistivity (ρ), where a lower resistivity indicates lower resistance and better conductivity of the metal.
Metals are known for easily losing outer shell electrons to form free electrons that create metallic bonds with metal ions, influencing their properties. However, conductivity strength is not solely determined by this characteristic. Factors like crystal structure, lattice arrangement, and other elements play significant roles in conductivity, regardless of the material type.
Three factors that affect the strength of metallic bonds
- The greater the atomic number, the farther the outermost electrons are from the atomic nucleus, leading to weaker binding of metal ions to free electrons, resulting in lower resistance and better conductivity.
The arrangement of outer electrons around the metal atomic nucleus.
Relativistic effects, caused by high-speed electron movement, impact outer electrons' orbital energy. As atomic number increases, electron energy and speed rise, intensifying these effects. This increases mass and energy consumption, ultimately reducing outer electron energy, contracting orbitals, strengthening metallic bonds, and decreasing conductivity.
The best conductor of electricity ranking of materials based on electrical conductivity from high to low：
Material | Resistivity (Ω·m) | Conductivity (S/m) |
Silver | 1.59×10-8 | 63×106 |
Copper | 1.68×10-8 | 59.6×106 |
Gold | 2.44×10-8 | 41×106 |
Aluminum | 2.82×10-8 | 35×106 |
5.60×10-8 | 17.9×106 | |
Zinc | 5.90×10-8 | 16.9×106 |
Nickel | 6.99×10-8 | 14.3×106 |
Lithium | 9.28×10-8 | 10.8×106 |
Iron | 1.0×10-7 | 10×106 |
Platinum | 1.06×10-7 | 9.43×106 |
Tin | 1.09×10-7 | 9.17×10>6 |
Stainless steel | 6.9×10-7 | 1.45×106 |
Mercury | 9.8×10-7 | 1.02×106 |
Silicon | 6.40×102 | 1.56×10-3 |
The advantages and applications of metals with good conductivity are as follows：
- Silver: Known for its exceptional electrical conductivity, silver is often used in high-end electronics and specialized applications where maximum conductivity is required. It is also highly ductile and corrosion-resistant.
- Copper: Widely used in electrical wiring and transmission due to its excellent conductivity, copper is relatively more affordable than silver and offers good overall performance in various applications.
- Gold: While expensive, gold boasts excellent electrical conductivity and is prized for its corrosion resistance, making it suitable for specific applications where these properties are crucial.
- Aluminum: With good conductivity and a lower cost compared to copper, aluminum is commonly used in power transmission lines, heat exchangers, and other applications where weight reduction is a priority.
- Tungsten: High melting point and good conductivity, used in electrical contacts, heating elements, and as an alloying agent.
Which metals are the best conductor of electricity?
As we explore materials science and engineering further, identifying the most optimal metal conductors is increasingly vital. Researchers and engineers are developing new alloy compositions and structures to enhance conductivity, strength, and corrosion resistance. By adjusting alloy properties, such as adding specific elements or modifying microstructures, they can create alloys with improved electrical performance for applications in electronics, aerospace, and automotive industries.
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