Why does copper conduct heat better than aluminium and iron?

[Alan Tam]

Why does copper conduct heat better than aluminium and iron? Could anyone help me answering the question? Thanks.

 

[ZapperZ]

At the simplest level, heat conductivity in metals is governed by two processes - the lattice vibrations and the transport of the free electrons. What makes a metal to be good heat conductors in general is predominantly due to these free electrons. So the rate of thermal conductivity depends on how easily they can move and "carry" the heat from one location to another (since the electron gas has very low specific heat, they absorb heat very easily and also gives off heat very easily).

At "high" temperatures (i.e. room temperature and above), the mechanism that dominates the electron transport in metals is the electron-phonon interaction. Phonons are lattice vibrations (read our FAQ in the General Physics forum if you want to learn more). The coupling between electrons and phonons in a solid is very complicated and depends on, for example, the phonon spectrum. Thus, this can vary from one material to another, and even in a material, can very in one direction versus another.

For copper, it has a relatively weaker electron-phonon coupling than, let's say, Pb and Al. So at a given temperature, the conduction electrons do not get "interfered" with the phonons as strongly as Pb and Al (or even Fe). So it can move more efficiently.

This is also the reason why Cu is also a better electrical conductor than most other metals at room temperature. Ironically, because of its weak coupling with the phonons, it doesn't have enough "glue" to form the necessary Cooper Pairs at very low temperatures and thus, it does not become a superconductor, whereas poorer conductors like Pb and Nb can, due to the stronger electron-phonon coupling strength.

Zz.

 

[charng]

Copper is a better conductor of heat than aluminium and iron due to its atomic structure. Copper has a higher number of free electrons, which are responsible for conducting heat. This is because copper has only one free electron in its outermost energy level, while aluminium has three and iron has eight. This means that copper has more free electrons available to transfer heat energy compared to aluminium and iron.

In addition, copper has a more compact and dense atomic structure compared to aluminium and iron. This allows for better contact between atoms, resulting in efficient transfer of heat energy. On the other hand, aluminium and iron have larger atomic sizes and less compact structures, which hinder the transfer of heat energy.

Furthermore, copper has a higher melting point than aluminium and iron, making it more resistant to heat damage. This allows for a consistent and efficient transfer of heat without the risk of melting or deforming.

Overall, the combination of a higher number of free electrons, compact atomic structure, and high melting point make copper a superior conductor of heat compared to aluminium and iron.