Guides/Comparisons
Aluminium nitride vs alumina
aluminium-nitride-vs-aluminaAluminium nitride (AlN) and Alumina (Al2O3) at a glance
This page compares Aluminium nitride (AlN) and Alumina (Al2O3) using only values that carry a source, a test condition and an evidence level. Ranges run across temper, heat treatment and product form, measured at room temperature where the source says so.
- Density: alumina is higher (AlN 3.25 to 3.3 g/cm³; alumina 3.72 to 3.9 g/cm³), about 1.2 times the midpoint of AlN.
- Young's modulus: alumina is higher (AlN 276 to 330 GPa; alumina 370 GPa), about 1.2 times the midpoint of AlN.
- Thermal conductivity: AlN is higher (AlN 140 to 180 W/(m·K); alumina 30 W/(m·K)), about 5.3 times the midpoint of alumina.
- Thermal expansion: alumina is higher (AlN 4.5 ppm/K; alumina 8.2 ppm/K), about 1.8 times the midpoint of AlN.
"Higher" means the whole range is higher, not just one value. Where a value is a specified minimum, the table says "at least".
Side by side
| Property | Aluminium nitride (AlN) | Alumina (Al2O3) |
|---|---|---|
| Density | 3.25 to 3.3 g/cm³ | 3.72 to 3.9 g/cm³ |
| Young's modulus | 276 to 330 GPa | 370 GPa |
| Thermal conductivity | 140 to 180 W/(m·K) | 30 W/(m·K) |
| Melting point | no data | 2,030 to 2,072 °C |
| Service temperature | no data | 1,750 °C |
| Thermal expansion | 4.5 ppm/K | 8.2 ppm/K |
Composition
| Element | Aluminium nitride (AlN) | Alumina (Al2O3) |
|---|---|---|
| Aluminium | not listed | 52.9% |
| Oxygen | not listed | 47.1% |
Shares are as printed in the sources, by weight.
When to use which
| Material | Best for | Weakest at |
|---|---|---|
| Aluminium nitride (AlN) | Electronic substrates, packages and heat spreaders where heat must leave a part without conducting electricity. | Water and humid storage: it hydrolyzes slowly, and the sources print no moisture limit. Thermal values also differ by grade. |
| Alumina (Al2O3) | Hard, stiff, electrically insulating parts that must stay stable at high temperature (CoorsTek chart: AD-995 volume resistivity above 10^14 ohm-cm at 25 °C) | Brittle fracture and sudden temperature change (fracture toughness 4 to 5 MPa·m½ for AD-995; thermal shock temperature difference of 200 °C for Kyocera's 99% grade) |
Where each is used
| Material | Use |
|---|---|
| Aluminium nitride (AlN) | Substrates for electronic packages, IC packages and power transistor bases |
| Aluminium nitride (AlN) | Heat sinks |
| Aluminium nitride (AlN) | Semiconductor heater plates and chucks |
| Alumina (Al2O3) | Semiconductor process chambers, wafer handling, laser devices and power tubes (ground industrial use) |
| Alumina (Al2O3) | Heat, corrosion and wear resistant parts (ground industrial use) |
| Alumina (Al2O3) | Sheath insulator layers for a thermionic space power system (ground reactor test, not flown) |
| Alumina (Al2O3) | Charge cup of the NASA standard initiator (thermal modelling, ground) |