Question

3 Алюминий применяют для изготовления электрических проводов. Объясните, с чем связана высокая электропроводность алюминия.

Answer 1

Ответ:

Электропроводность алюминия растет с уменьшением количества примесей. Температурный коэффициент электросопротивления алюминия (0.004) приблизительно такой же, как у меди. Теплопроводность алюминия при 20 С составляет примерно 0.50 кал/см*с*С и возрастает с увеличением чистоты металла.

Answer 2

The High Electrical Conductivity of Aluminum

Aluminum is widely used in the manufacturing of electrical wires and cables due to its high electrical conductivity. The high electrical conductivity of aluminum is primarily attributed to the following factors:

1. Atomic Structure: Aluminum has a unique atomic structure that contributes to its high electrical conductivity. It has 13 electrons arranged in three energy levels or shells. The outermost shell of aluminum contains just three valence electrons, which are loosely held by the nucleus. These loosely held electrons can move freely within the metal lattice, allowing for the easy flow of electric current.

2. Metallic Bonding: Aluminum exhibits metallic bonding, which is a type of chemical bonding that occurs between metal atoms. In metallic bonding, the valence electrons are delocalized and form a "sea" of electrons that are free to move throughout the metal lattice. This delocalization of electrons enables the efficient transfer of electric charge, resulting in high electrical conductivity.

3. Low Resistivity: Aluminum has a relatively low resistivity, which is a measure of how strongly a material opposes the flow of electric current. The resistivity of aluminum is approximately 2.65 x 10^-8 ohm-meters, which is lower than many other metals commonly used in electrical applications. The low resistivity of aluminum allows for the efficient transmission of electric current through the wires and cables made from this metal.

4. Lightweight: Another advantage of aluminum is its lightweight nature. Compared to other metals like copper, aluminum has a lower density, which means that a given volume of aluminum weighs less than an equivalent volume of copper. This lightweight property makes aluminum an attractive choice for applications where weight reduction is important, such as in the aerospace industry.

It is important to note that while aluminum offers high electrical conductivity, it does have some limitations. For instance, aluminum has a lower tensile strength compared to copper, which means it is more prone to breakage under tension. Therefore, aluminum wires and cables are often reinforced with other materials or used in applications where tensile strength is not a critical factor.

In conclusion, the high electrical conductivity of aluminum is due to its atomic structure, metallic bonding, low resistivity, and lightweight nature. These properties make aluminum an excellent choice for the production of electrical wires and cables.