Metals are known to be a good conductor of heat and as such they are widely integrated in electronic devices as well as printed circuit boards. While some metals don’t really perform well, some metals have low thermal conductivity. Materials with low thermal conductivity are known to be a good insulator.
In addition, metals that feature a high rate of thermal conductivity transmit heat rapidly. On the other hand, some metals with low thermal conductivity function as thermal insulators and as such, prevent heat transfer.
What is Thermal Conductivity?
Thermal conductivity is one of the properties of metal. It is a property that evaluates the capability of a metal to conduct heat. Thermal conductivity of a metal varies based on the type of metal. Therefore, it is important to consider the thermal conductivity of the metal type in applications where there are high operating temperatures.
Thermal conductivity always remain the same in pure metals most times. It doesn’t really changes with increase in temperature. However, there are some metal types like alloys that experiences increase in thermal conductivity in response to temperature.
Also, the thermal conductivity of metal is a basic property. Regulating the transfer of heat is a crucial design consideration in printed circuit boards and electronic devices.
What is the Thermal Conductivity of Metals?
The thermal conductivity of a metal defines its capability to transfer or conduct heat. Metal have a good thermal conductivity. However, temperature can have an impact on the thermal conductivities of metals. The presence of free electrons in metal contributes to its heat conductivity. A pure metal’s electrical conductivity reduces when temperature increases.
Metals are materials with high thermal conductivity. Therefore, they conduct heat faster. In metals, there are free electrons and this results in the conduction which results in electronic conduction. Free electrons can move throughout metals and as such can quickly transfer thermal energy compared to insulators. Also, metals with the simplest electrical conductors have the best thermal conductivity.
In metals, thermal conduction is in three different categories for various forms. These are conduction electrons for metals, molecular collisions for gas or liquid forms, and lattice vibrations for solids. There are various process of metal s’ thermal conduction. These include lattice vibrations and conducting electrons for metals and molecular collisions combined with the conduction electrons for metals. What really makes metal a good conductor is the presence of conduction electrons.
The free flow of conduction electrons contributes to metal’s ability to conduct heat. Metal atoms offer valence electrons while still reacting with non-metal atoms chemically. Therefore, metal ions perform well when used in some applications. The special metallic bonding of metals and metal alloys makes them good conductors. Metals are known to be very ductile and malleable and as such they deform when exposed to stress.
Materials with low thermal conductivity prevent the transfer of heat. This helps in achieving enhanced energy efficiency and better stability of the material. For instance, the lower thermal conductivity of steel makes it an ideal option for developing and designing facades, glass applications, etc.
The Thermal Conductivity of Different Types of Metals
There are different types of metals and each of these metals feature different thermal conductivity. Metals serve a lot of functions in different applications. They are widely used in the manufacturing of printed circuit boards.
Thermal conductivity of aluminum
Aluminum in its pure form features a thermal conductivity of almost 235 watts for each Kelvin per meter. However, aluminum alloys feature lower thermal conductivity. Aluminum is a good metal option for electronic heat sinks. This is because of its good thermal conductivity.
Thermal conductivity of stainless steel
Stainless steel is a metal with low thermal conductivity. Therefore, this material prevents the transfer of heat. The thermal conductivity of stainless steel is said to be 15 watts per Kelvin for each meter. Stainless steel is a type of metal commonly used for structures in corrosive environments.
Thermal conductivity of carbon steel
Carbon steel is another type of metal. This metal has a lower thermal conductivity compared to aluminum. The thermal conductivity of carbon steel is measured at 45 W/mK. Carbon steel is a cost-effective option for developing structural components. This steel type has small traces of other elements asides from iron and carbon. This steel type is the more commonly used than other types of steel.
Thermal conductivity of Bronze
Bronze is an alloy that comprises nickel, aluminum, and copper. It is known for its exceptional thermal conductivity. Bronze’s thermal conductivity ranges from 50 -120 W/mK. However, this depends on the content of copper present in bronze.
Metals with Low Thermal Conductivity
Metals serve a lot of functions in different applications. They are widely used in the manufacturing of printed circuit boards. Also, these materials are a great building material option. Metals are known for their crucial roles in electronics manufacturing. The thermal conductivity of metals varies based on their type. Here, we will be discussing metals with low thermal conductivity.
Steel
Steel features the lowest thermal conductivity and as such it is a great option for applications in high-temperature environments. As the lowest thermal conductivity metal, steel has about 45 W/mK. This is much lower than other metals like aluminum and copper which has about 235 W/mK and 398 W/mK respectively.
There are different types of steel. Steel’s versatility and its thermal properties make it a popular metal that has dominated several industries. Steel as one of the lowest thermal conductivity metals is commonly integrated for the production of medical devices, kitchen equipment, and more. There are four different types of steel. These are stainless steel, copper steel, alloying steel, and tool steel
Out of all these types of steel, stainless steel the lowest thermal conductivity metal with a thermal conductivity of 15 W/mK. Therefore, this metal can absorb more energy which stabilizes the temperature of the environment. Stainless steel has the lowest thermal conductivity amongst other types of steel. The thermal conductivity of this material doesn’t change in response to variation in temperature.
Bronze
Bronze is one of the lowest thermal conductivity metal. Bronze’s thermal conductivity ranges from 50 -120 W/mK. However, this depends on the content of copper present in bronze.
Benefits of Metals with Low Thermal Conductivity
Metals with low thermal conductivity offer a lot of benefits. Due to their ability to retain heat, these metals have found their use in different applications. Lowest thermal conductivity metals are commonly integrated for the production of medical devices, kitchen equipment, and more.
Materials with low thermal conductivity prevent the transfer of heat. This helps in achieving enhanced energy efficiency and better stability of the material. For instance, the lower thermal conductivity of steel makes it an ideal option for developing and designing facades, glass applications and more. Also, low thermal conductivity metals maintain their stability when they come in contact with heat, like during food processing equipment like ovens.
Furthermore, lowest thermal conductivity metals make it crucial for designing any structure. These metals play an integral role in the security and new innovations within several industries. Metals with low thermal conductivity are known for transferring heat slowly. Therefore, these types of materials are usually integrated in applications that are exposed to a high level of temperature.
Metals with low thermal conductivity are known to be a good insulator. PCBs used in high frequency and high performance applications usually require lowest thermal conductivity metal. Also, metals with low thermal conductivity offer improved thermal performance.
Applications that Require High Thermal Conductivity Metals
Not all applications require low thermal conductivity, some applications require an exceptional thermal conductivity. Some examples are below
Heat exchanger
A heat exchanger transfers heat in order to achieve cooling or heating. Copper is the main metal used in heat exchangers. However, aluminum is also an alternative. Both copper and aluminum conduct heat faster. A car radiator is an example of a heat exchanger. The radiator comprises layers of metal sheets stacked with aluminum core.
Furthermore, heat exchangers are widely integrated in aircraft engines. They help to get rid of excess heat in power supplies and military equipment. Hot water tanks, air conditioning, and refrigeration need heat exchangers.
Heat sinks
Heat sinks are designed to transmit heat produced by a mechanical or electronic device in a moving fluid. Metals like aluminum alloys are commonly used in heat sinks. Computers have heat sinks to help them cool the CPU or graphic processors. Also, high power devices like light emitting diodes (LEDs) and power transistors have heat sinks.
Cookware
Cookware makes use of metal with exceptional thermal conductivity. Also, copper is a high thermal conductivity metal used in the bottom of cookware since it conducts heat faster.
Conclusion
Thermal conductivity is an important property of metals. While some metals have a low thermal conductivity, some have high thermal conductivity. In this article, we focused mainly on metals with low thermal conductivity. Also, from this article, we realized that steel and bronze are a good example of metals with low thermal conductivity. These metals are known to be good insulators due to their low thermal conductivity.
