Is Metal an Insulator? (+ 3 Things to Know)

No, metals are not considered insulators. Metals are known as conductors of electricity due to their ability to readily allow the flow of electrons. They have a high electrical conductivity and a low electrical resistance, making them efficient in conducting electric current. ¹

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why are metals a conductor?

Metals are excellent conductors of electricity due to their unique atomic structure and the behavior of their electrons. In a metal, the outermost electrons, known as valence electrons, are loosely bound to the atomic nuclei and are free to move throughout the metal lattice. These mobile electrons are often referred to as a “sea of electrons.” ^{2 3}

When an electric field is applied to a metal, the valence electrons respond by moving in the direction of the field. This movement creates a flow of charge, or an electric current, through the metal.

The delocalized nature of the electrons allows them to easily transfer energy and carry electrical charge from one atom to another, facilitating the conduction of electricity.

Moreover, metals have a high number of free electrons, making them good conductors of both heat and electricity. ⁴ Their dense and orderly arrangement in a metallic lattice further enhances their conductivity.

These factors contribute to metals’ ability to conduct electricity efficiently, making them vital components in electrical wiring, circuits, and various electrical devices.

How does the temperature affect the electrical conductivity of metals?

The temperature has a significant impact on the electrical conductivity of metals. As the temperature increases, the conductivity of most metals generally decreases. ⁵

This phenomenon can be explained by the interaction between temperature and the movement of electrons in the metal lattice. At lower temperatures, the lattice vibrations are minimal, and there are fewer collisions between the electrons and lattice ions. This results in a smoother flow of electrons and higher conductivity.

However, as the temperature rises, the lattice vibrations become more pronounced. These vibrations can disrupt the movement of electrons, leading to more frequent collisions. The collisions scatter the electrons, impeding their flow and reducing the overall conductivity of the metal.

Additionally, increasing temperature can cause some metals to undergo a phase transition, such as melting or transitioning from a crystalline to an amorphous state. ⁶ These transitions can further disrupt the orderly arrangement of atoms and negatively impact conductivity.

It is worth noting that the relationship between temperature and conductivity can vary depending on the specific metal and its properties.

Some metals, like semiconductors, may exhibit an increase in conductivity with temperature due to the specific behavior of their electron energy bands. However, for most metals, the general trend is a decrease in conductivity with increasing temperature.

Methods used to improve the conductivity of metals

There are several methods used to improve the conductivity of metals, including:

• Alloying: Adding small amounts of other metals or elements to the base metal can enhance its conductivity. ^{7 8} For example, copper alloys with elements like silver or phosphorus can increase its electrical conductivity while maintaining other desirable properties.
• Annealing: Annealing involves heating the metal to a specific temperature and then slowly cooling it. This process helps remove defects and dislocations in the metal’s crystal structure, improving its conductivity.
• Purification: Impurities in metals can disrupt the movement of electrons and reduce conductivity. Purification techniques, such as electrolysis or vacuum distillation, help remove impurities and enhance the metal’s conductivity.
• Cold working: Cold working refers to deforming the metal at room temperature through processes like rolling, drawing, or forging. This mechanical deformation can align the metal’s crystal structure, reducing grain boundaries and improving conductivity. ⁹
• Surface treatment: Coating the metal’s surface with a thin layer of a highly conductive material, such as silver or gold, can improve its conductivity. This is commonly used in electrical connectors or contacts.
• Electroplating: Electroplating involves depositing a layer of a more conductive metal onto the surface of the base metal. ¹⁰ This can improve conductivity while also providing additional benefits like corrosion resistance.

These methods are utilized based on the specific requirements and properties of the metal, aiming to enhance its electrical conductivity for various applications.

Further reading

Is Rubber a Conductor?
Why is Silver a Conductor?
Why is Gold a Conductor?
Why is Brass a Conductor?
Is Carbon a Conductor? 

1. Electrical conductor – Wikipedia. (2018, January 14). Electrical Conductor – Wikipedia. https://en.wikipedia.org/wiki/Electrical_conductor
2. Metallic bond | Properties, Examples, & Explanation. (n.d.). Encyclopedia Britannica. https://www.britannica.com/science/metallic-bond
3. Oregonstate.edu https://web.engr.oregonstate.edu/~traylor/ece112/beamer_lectures/electrons_and_conductors.pdf
4. Nde-ed.org https://www.nde-ed.org/Physics/Electricity/conductorsinsulators.xhtml
5. 6.8A: Electrical Conductivity and Resistivity. (2013, October 2). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Map%3A_Inorganic_Chemistry_(Housecroft)/06%3A_Structures_and_Energetics_of_Metallic_and_Ionic_solids/6.08%3A_Bonding_in_Metals_and_Semicondoctors/6.8A%3A_Electrical_Conductivity_and_Resistivity
6. Cheng, S. Z. (2008). Thermodynamics and Kinetics of Phase Transitions. Phase Transitions in Polymers, 17–59. https://doi.org/10.1016/b978-0-444-51911-5.00002-5
7. Cui, X., Wu, Y., Zhang, G., Liu, Y., & Liu, X. (2017, February). Study on the improvement of electrical conductivity and mechanical properties of low alloying electrical aluminum alloys. Composites Part B: Engineering, 110, 381–387. https://doi.org/10.1016/j.compositesb.2016.11.042
8. Abdo, H. S., Seikh, A. H., Mohammed, J. A., & Soliman, M. S. (2021, July 16). Alloying Elements Effects on Electrical Conductivity and Mechanical Properties of Newly Fabricated Al Based Alloys Produced by Conventional Casting Process. Materials, 14(14), 3971. https://doi.org/10.3390/ma14143971
9. Cold working – Wikipedia. (2021, August 1). Cold Working – Wikipedia. https://en.wikipedia.org/wiki/Cold_working
10. Electroplating. (2013, October 2). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Electrochemistry/Electrolytic_Cells/Electroplating