Aluminum nitride ceramic solid round rod

-Aluminium nitride has a very high thermal conductivity compared to most ceramics. In fact, AlN has one of the highest thermal conductivities of any ceramic, second only to beryllium oxide. For single-crystal AlN, this value can be as high as 285 W/(m-K). However, for polycrystalline materials, values in the range of 70-210 W/(m-K) are more common.

-The high thermal conductivity of aluminium nitride is due to its low molar mass (40.99 g/mol compared to 101.96 g/mol for aluminium oxide Al2O3), strong bonding and relatively simple crystal structure. Further properties of aluminium nitride are compared below with other similar technical ceramics.

- Aluminium nitride has a coefficient of thermal expansion of 4.8 ✕ 10 -6 1/K at 20 °C. This is very similar to silicon (3.5 ✕ 10 -6 1/K at 20 °C), which is why AlN is often used as a substrate material for silicon processing.

- Other properties of aluminium nitride relevant for use at high temperatures are high thermal shock resistance and resistance to corrosion by molten metals, chemicals and plasma at high temperatures.

- Aluminium nitride has a melting point of 2,200°C and a boiling point of 2,517°C.

Similar to other ceramics, AlN has a very high resistivity in the range of 10-16 Ω-m. This makes it an electrical insulator.

AlN also has a relatively high dielectric constant of 8.8-8.9 (pure AlN), which is similar to that of Al 2 O 3 but much lower than that of SiC.

The breakdown electric field of AlN is 1.2-1.8 x 10 6 V cm -1 .

AlN also displays piezoelectricity, which is useful in thin film applications.

The flexural strength of AlN at 20°C is 350 MPa, which is the same as Al 2 O 3 and slightly lower than SiC.

It has a high Young's modulus of 343 GPa compared to steels in the 200 GPa range. This value is just below that of Al 2 O 3 .

AlN also has a high Vickers hardness of about 1000 at 20 °C.