How Does The Thermal Expansion Coefficient Of Aluminium Nitride Compare To Other Materials?

Aluminum nitride has a relatively low coefficient of thermal expansion (CTE) compared to many other materials. The CTE of a material is a measure of how much it expands or contracts when its temperature changes. Aluminum nitride has a CTE of approximately 4.5 ppm/K at room temperature, which means that for every degree increase in temperature, it will expand by about 4.5 parts per million (ppm) of its original size.

In contrast, some other common materials have much higher CTEs. For example, the CTE of steel is around 12 ppm/K, while the CTE of copper is around 17 ppm/K. This means that these materials will expand or contract much more than aluminum nitride for a given change in temperature.

However, there are also materials with lower CTEs than aluminum nitride. For example, some ceramics and glasses have CTEs as low as 1-2 ppm/K. In addition, some composite materials can be engineered to have even lower CTEs.

Overall, while aluminum nitride may not have the lowest CTE of all materials, its relatively low value makes it useful for applications where thermal stability is important, such as in electronic components and substrates used in high-power electronics.