How Thermal Conductivity Materials Are Measured

Aerospace materials must meet stringent requirements regarding thermal conductivity. These include high-level insulation, low coefficient of thermal expansion (CTE), and fire resistance. They must also have high conductivity in order to manage heat within the insulation layer and provide rapid cooling.

Understanding Thermal Conductivity Materials depends on the type of material and the structure in which it is formed. The crystalline structure and the size of the crystal atoms affect the material’s conductivity, with larger crystals having higher conductivity than smaller ones. The chemical inertness of a material is also an important factor. For example, tungsten has very high conductivity but has a very low melting point and vapor pressure. This makes it useful in arcs used in light bulbs and cathode ray tubes, where there is no possibility of the metal melting or reacting with other chemicals present.

Copper is one of the most commonly employed conductive metals because it has high thermal conductivity and a relatively low cost. It can withstand harsh environmental conditions and corrodes very little, making it ideal for pans and pipes. Other metals with high thermal conductivity include silver, gold, and tungsten.

In addition to a material’s size and crystal structure, the porosity of a material can also affect its thermal conductivity. The presence of voids within a material can reduce its overall thermal conductivity because they act as barriers to the flow of free electrons.

Another important consideration is the fact that a material’s thermal conductivity can change with temperature. This can make it difficult to predict how a material will perform in certain applications. A material’s thermal conductivity will also vary depending on the direction in which it is measured.

A new method has been developed for measuring the thermal conductivity of a material using a laser. The process involves a laser beam being directed over the surface of the material while the temperature of the material is monitored with an infrared detector. The result is a measurement of the thermal conductivity of the material in the form of a graph.

While many different factors influence a material’s thermal conductivity, there are some general rules that can be applied. The thermal conductivity of a material increases as the thickness and density of the material decreases, but it is not proportional. A thinner, denser material will have a lower thermal conductivity than a thicker, sturdier one.

For aerospace applications, thermal interface materials (TIMs) must be very high in thermal conductivity and have a low CTE to ensure the proper transfer of heat from the printed circuit board (PCB) to the substrate. Without the correct TIMs, thermal stress can lead to performance and reliability issues. Ideally, the TIM should be as close to the CTE of the PCB as possible.