Aluminum is a conductor of electricity, widely utilized in various electrical applications. Its ability to efficiently transmit electric current stems from its atomic structure and atomic bonding.
How Aluminum Conducts Electricity
Aluminum conducts electricity due to the presence of delocalized electrons within its metallic structure. In metals like aluminum, atoms are held together by metallic bonds, where their outermost electrons are not bound to a single atom but instead form a “sea” of electrons that can move freely throughout the material. Each aluminum atom contributes three such electrons to this electron sea.
When an electrical voltage is applied across a piece of aluminum, these free electrons are able to move in a directed manner, creating an electric current. This flow enables aluminum to transmit electricity efficiently. The crystal structure of aluminum, specifically its face-centered cubic arrangement, also facilitates the free movement of these electrons, further enhancing its conductivity.
Aluminum’s Conductivity Compared to Other Metals
Aluminum’s electrical conductivity is considerable, though it is not the highest among all metals. Silver holds the highest electrical conductivity, followed closely by copper. Aluminum typically exhibits about 61% of copper’s conductivity by volume.
The International Annealed Copper Standard (IACS), adopted in 1913, serves as a reference point, defining pure annealed copper as having 100% conductivity. However, when considering conductivity by weight, aluminum offers nearly twice the conductivity of copper due to its significantly lower density. This makes aluminum a material of choice in applications where weight reduction is a factor.
Practical Applications of Aluminum’s Conductivity
Aluminum’s electrical conductivity, combined with other properties like its low density and cost-effectiveness, makes it suitable for many practical applications. It is extensively used in overhead power transmission lines where its lightweight nature allows for longer spans between support towers, reducing infrastructure costs. The natural oxide layer that forms on aluminum also provides a degree of corrosion resistance, contributing to the durability of these lines.
In residential and commercial buildings, aluminum has been used for electrical wiring. While early forms of aluminum wiring used in homes between the mid-1960s and late 1970s presented some challenges due to material properties and connection issues, modern aluminum alloys and installation techniques have addressed these concerns.
Aluminum is also widely employed in busbars, which are rigid electrical conductors used in power distribution systems within buildings and electrical panels. Its light weight and ability to handle substantial current loads are beneficial.