The thermal conductivity of any physical material is a measure of its potential to conduct heat. In materials of low thermal conductivity, heat transfer occurs at a lower rate than in materials of high thermal conductivity. For example, metals typically have high thermal conductivity and are very efficient at conducting heat, while the other is true for insulating materials like Styrofoam. Let us study the Thermal Conductivity of Metals in detail.
What is the Thermal Conductivity of Metals?
In the case of metals, there are a high amount of free electrons, and hence heat conduction primarily leads to electronic conduction. In metals, the free electrons can move freely throughout the solid and thus transfers the thermal energy at a very high rate as compared to insulators. Also among the metals, the simplest electrical conductors also exhibit the best thermal conductivity.
Modes of Warmth Transfer of Metals
Thermal conduction is further divided into three categories for different forms: molecular collisions occurs in the case of gas/liquid forms, lattice vibrations for solids and conduction electrons for metals. The various process of thermal conduction of metals includes molecular collisions + conduction electrons for metals in the gas state, and lattice vibrations + conducting electrons for metals in solid-state. Conduction electrons are essentially what makes a metal a fantastic conductor.
Why Metals are Good Thermal Conductors?
What makes a metal an honest thermal conductor are the free-flowing conduction electrons. Metal atoms give out valence electrons while chemically reacting with non-metal atoms, like forming oxides and salts. Thus, metal ions are cations in a solution. What makes metals and metal alloys good conductors is that the special metallic bonding.
Metal solids have bonded atoms that share their valence electrons. This sharing of electrons creates a sea of freely moving conduction electrons which carry both heat and electrical charge. So, unlike electrons in covalent bonds, the valence electrons within a metal can freely flow through the metal lattices, efficiently carrying heat without being locked to a private atomic core.
Uses of Metals as a Conductor
- Metals and alloys (materials made from a mixture of metals) are useful as building materials in several industries like electronics, engineering, laboratory equipment, medical devices, household products, and construction.
- Silver has the highest thermal conductivity value among metals. It is -429 W/m•K, Copper is -398 W/m•K and Gold is -315 W/m•K.
- Metals are highly important in making electronics as they are good conductors of electricity. Copper, aluminium, tin, lead, magnesium and plastic are often useful in making parts of phones, laptops, computers and automotive electronics.
- Copper is cost-efficient and useful for electrical wiring.
- Lead is useful for cable sheathing and making batteries. The thermal conductivity of metal is extremely important for designing any structure. It’s very much integral for the security, efficiency and new innovations within industries.
- The conductor electrons are the mechanism behind the high conductivity of metals as compared to non-metal materials.
FAQs about Thermal Conductivity of Metals
Q.1. What is the effect of temperature on the thermal conductivity of metals?
Answer: In the case of pure metals and alloys, the thermal conductivity predominantly depends on the electronic effect. As temperature increases, both the number of free electrons and lattice vibrations increase. Thus the thermal conductivity of the metal is expected to increase.