A material’s ability to conduct heat essentially reflects how quickly it can absorb heat from areas of high temperature and move it towards areas of lower temperature. Also known as thermal conductivity, this property is important for many different applications, including cookware, heat exchanges, and heat sinks.
Conversely, the quick transfer of heat is not always welcome, and therefore materials with a lower propensity for heat conduction can come in handy too. These heat conducting materials play a vital role in how electronic cabinets and vortex cooler systems work.
Here’s an overview of some from highest to lowest of the most common heat conducting materials.
Silver has the highest thermal conductivity of any element. Due to silver’s valance and crystal structure, the electrons of silver are freer to move than those of other elements. These heat conducting materials are also very expensive and not very resistant.
Although silver is one of the best heat conducting materials, copper and gold are used more often in electrical applications because copper is less expensive, and gold has a much higher corrosion resistance. Silver is also inclined to tarnish, and it loses some of its conductive power during this process.
Much cheaper and more readily available than silver, copper also has a very high thermal conductivity. Thanks also to its ability to resist corrosion and biofouling, copper is considered the best overall material for conducting heat. These properties also make it ideal for any function that involves water, moisture, or changes in humidity, including: solar water heaters, gas water heaters, and industrial heat exchangers, refrigerators, air conditioners, and heat pumps.
Not quite up to par with copper in terms of its ability to conduct heat, aluminum does have the advantage of being very light, easy to work with, and more economical. The fact that it is more easily pliable also makes it preferable for some applications.
One of the most recent and innovative uses for aluminum as a conductor of heat includes microelectronics such as LEDs and laser diodes. These heat conducting materials use tiny heat sinks with aluminum fins that project into the air. The heat generated by the electronics transfers from the chip to the aluminum and then to the air, either passively or with the help of forced airflow convection or a thermoelectric cooler.
4. Copper brass
Brass is an alloy of copper and zinc, the proportions of which can vary and therefore produce brasses with different properties. Overall, brass has excellent thermal conductivity and is a common choice for heat exchangers. Brass also acts as a standard by which the machinability of other materials is judged, as it does not become brittle at low temperatures like mild steel.
Interestingly, brass also offers the unique quality of disinfection, as common pathogens die on its surface within hours.
Like brass, bronze is an alloy of copper and usually tin. With tin as the main additive, it is much harder and more brittle than brass. In general, the term “bronze” is used interchangeably for different types of copper alloys, but the most common typically refers to a mix of about 90% copper and 10% tin in its “pure” form.
An additive such as lead can also be used to make bronze more castable, whereas phosphorous will harden it. Due to the fact that bronze creates very little friction and does not spark, these heat conducting materials are ideal for metal on metal contact applications such as gears.
With just a slightly lower conductivity rating than bronze, iron is still the most frequently encountered metal in daily life. We see iron most commonly in the form of manufactured objects, and usually covered with a protective coating or buried deep within the object. Iron interiors often needed to be coated due to the metal’s propensity to rust. Another shortcoming is its weight.
Lead is very soft, highly malleable, ductile, and therefore is a relatively poor conductor of electricity and heat. A strength is that it is very resistant to corrosion, but it also tarnishes upon exposure to air. Despite its low thermal conductivity, lead has many applications, including being used as a coloring element in ceramic glazes, as projectiles, and in some candles to threat the wick.
Other uses for lead include sheeting, cables, solders, lead crystal glassware, ammunitions, bearings and as weight in sport equipment.
8. Stainless Steel
With one of the lowest thermal conductivities for a metal alloy, stainless steel takes significantly longer to conduct heat away from a source than an alternative like copper. This means that a pot made of stainless steel would take much longer to heat up food than a copper-bottom pot.
Nevertheless, stainless steel offers other benefits, and steam and gas turbines in power plants actually use stainless steel because of its heat resistance, among other properties. Its low thermal conductivity also comes in handy in architecture, as stainless-steel cladding can resist high temperatures longer, it is able to keep buildings cooler even in direct sunlight.