Materials Performance: Conductivity

Understanding Conductivity

Conductivity is the property of a material that allows it to transmit heat or electricity.
It is typically measured in terms of thermal conductivity (for heat) and electrical conductivity (for electricity).
All materials have a degree of conductivity, but some are specifically chosen for their ability to conduct or resist heat or electricity.

Thermal Conductivity: This term refers to the amount of heat a particular material can conduct. For example, metals typically have high thermal conductivities because of their closely packed atomic structures.
Electrical Conductivity: This measures the extent to which a material can conduct an electric charge. Again, metals tend to be excellent conductors because of their free-moving electrons.
Insulators: These are materials with low conductivities that are designed to slow or stop the flow of heat or electricity, like foam or rubber.
Ohm’s Law: This law states that the current through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance.

Metals such as copper, silver, and gold are traditionally used for their high electrical conductivity.
Ceramics contain atoms bonded with ionic and covalent bonds, giving them high thermal resistance, making them good insulators.
Certain types of plastics, like polyethylene and polypropylene, are generally good thermal and electrical insulators but can be modified to conduct electricity (conductive polymers).

Generally, for most conductors, conductivity tends to decrease as temperature increases.
However, semiconductors, such as silicon, show an increase in conductivity with increasing temperature.
Understanding the relationship between temperature and conductivity is crucial when choosing materials for applications where heat or electrical currents are involved.

Conductivity is considered in the design and manufacturing of a wide range of products, spanning sectors such as electronics, building, automotive, and more.
For example, the high electrical conductivity of copper and gold makes them ideal for electrical wiring, while the low thermal conductivity of insulation materials like foam makes them suitable for insulating homes.
On the other side, a high thermal conductivity is desired for materials used in cooling elements or heat sinks.