About Aluminum Nitride
Aluminum Nitride (AlN) is an excellent material to use if high thermal conductivity and electrical insulation properties are required; making it an ideal material for use in thermal management and electrical applications. Additionally, Aluminum Nitride is common alternative to Beryllium Oxide (BeO) in the semiconductor industry as it is not a health hazard when machined. Aluminum Nitride has a coefficient of thermal expansion and electrical insulation properties that closely matches that of Silicon wafer material, making it an useful material for electronics applications where high temperatures and heat dissipation is often a problem.
AlN commonly comes in substrates up to 1 mm thick which can easily be laser cut. It can also come in thicker forms, however, it can be difficult/costly to manufacture in small quantities if the part requires custom material or significant machining. Shapal Hi-M Soft is often used as an alternative to pure aluminum nitride because it also offers high thermal conductivity and can be machined into complex geometries.
Aluminum Nitride Properties
- High thermal conductivity
- Low coefficient of thermal expansion
- Good electrical insulation and resistivity
- Low dielectric constant
- High mechanical strength under compression load
- Corrosion resistant (gas)
- Good thermal shock resistance
Aluminum Nitride Engineering Properties
|Modulus of Elasticity||GPa||310|
|Fracture toughness||Mpa x m^1/2||3.5|
|Hardness (Knoop 100 g)||Kg/mm2||1170|
|Maximum Temperature *|
|Thermal Shock Resistance ΔT||°C||400|
|Coefficient of Expansion|
|CTE 25°C ➞ 100°C||10^-6/°C||3.6|
|CTE 25°C ➞ 300°C||10^-6/°C||4.6|
|CTE 25°C ➞ 500°C||10^-6/°C||5.2|
|CTE 25°C ➞ 1000°C||10^-6/°C||5.6|
|Dielectric Constant||1 MHz||8.6|
|Loss Tangent||1 MHz||5x10^-4|
* Note – Aluminum Nitride is susceptible to surface oxidization. When this happens, a layer of Aluminum Oxide forms. This does help to protect the material, however, it impacts the thermal conductivity (Alumina is ~30 W/m.K). In oxidizing atmospheres, this happens around 700°C. In inert atmospheres this layer protects the AlN up to ~1350°C. Bulk oxidation will occur at temperatures above this.
Aluminum Nitride Applications
- Heat sinks & heat spreaders
- Electrical insulators for lasers
- Chucks, clamp rings for semiconductor processing equipment
- Electrical insulators
- Silicon wafer handling and processing
- Substrates & insulators for microelectronic devices & opto electronic devices
- Substrates for electronic packages
- Chip carriers for sensors and detectors
- Laser heat management components
- Molten metal fixtures
- Packages for microwave devices
Aluminum Nitride for Thermal Management of Electronic Devices
Aluminum Nitride is one of the few materials that offers electrical insulation and high thermal conductivity. This makes AlN extremely useful in high power electronic applications in heat sink and heat spreader applications. Other materials that are commonly used are boron nitride, Shapal Hi-M Soft, beryllium oxide, and sometimes alumina.
Aluminum Nitride Machining & Grinding
Aluminum Nitride can be machined in green, biscuit, or fully dense states. While in the green or biscuit form it can be machined relatively easily into complex geometries. However, the sintering process that is required to fully densify the material causes the Aluminum Nitride body to shrink approximately 20%. This shrinkage means that it is impossible to hold very tight tolerances when machining Aluminum Nitride pre-sintering.
In order to achieve very tight tolerances, fully sintered material must be machined/ground with diamond tools. In this process a very precise diamond coated tool/wheel is used to abrade away the material until the desired form is created. Due to the inherant toughness and hardness of the material, this can be a time consuming and costly process. Shapal Hi-M Soft is often used as a substitute for pure AlN because it also offers high thermal conductivity, electrical insulation, and can be machined into complex geometries with tight tolerances.
Buy Custom Aluminum Nitride Components
Precision Ceramics is your Aluminum Nitride machining specialist for your technical ceramic prototyping & manufacturing needs; we are always happy to use our many years of advanced ceramics experience to provide advice on materials, design, and application. If you would like to buy Aluminum Nitride plates, rods, tubes or custom machined components, or need more information, please contact us and one of our experts will be happy to assist you.