Aluminum Nitride (AlN) is an atomic crystal belonging to diamond-like nitrides, which can maintain stability up to 2200°C. It exhibits high strength at room temperature, and its strength decreases relatively slowly with the increase in temperature. Boasting excellent thermal conductivity and low thermal expansion coefficient, AlN is an outstanding material for thermal shock resistance. Its strong resistance to molten metal erosion makes it an ideal crucible material for melting and casting pure iron, aluminum, or aluminum alloys. Additionally, AlN is an electrical insulator with good dielectric properties, showing promising potential for use as electrical components. An AlN coating on gallium arsenide surfaces can protect it from ion implantation during annealing.
Furthermore, AlN serves as a catalyst for the transformation from hexagonal boron nitride to cubic boron nitride. At room temperature, it reacts slowly with water. AlN can be synthesized by reacting aluminum powder in an ammonia or nitrogen atmosphere at 800-1000°C, resulting in a white to gray-blue powder. Alternatively, it can be synthesized from the Al2O3-C-N2 system at 1600-1750°C, yielding a gray-white powder. It can also be obtained through a gas-phase reaction between aluminum chloride and ammonia. Coatings can be synthesized by the gas-phase deposition method using the AlCl3-NH3 system.
Properties
High thermal conductivity (approximately 20 W/m·K), comparable to BeO and SiC, and over 5 times that of Al2O3.
Thermal expansion coefficient (4.5×10-6°C) that matches well with Si (3.5-4×10-6°C) and GaAs (6×10-6°C).
Excellent electrical properties, including dielectric constant, dielectric loss, bulk resistivity, and dielectric strength.
Superior mechanical properties, with higher flexural strength than Al2O3 and BeO ceramics, allowing for sintering at atmospheric pressure.
High purity.
Excellent optical transmission characteristics.
Suitable for tape casting process, making it a promising substrate and packaging material for high-power integrated circuits.
Applications
AlN finds applications in optoelectronics, including as a dielectric layer in optical storage interfaces and electronic substrates, as a chip carrier due to its high thermal conductivity, and for military purposes.
Leveraging its piezoelectric effect, the epitaxial extension of AlN crystals is used in surface acoustic wave detectors, which are placed on silicon wafers. Only a few locations can reliably produce these thin films.
Utilizing its high room and high-temperature strength, low expansion coefficient, and good thermal conductivity, AlN ceramics can be used as high-temperature structural components and heat exchanger materials.
Given its resistance to corrosion by metals and alloys such as iron and aluminum, AlN ceramics can serve as crucibles and casting molds for melting and casting metals like Al, Cu, Ag, and Pb.
Hot Tags: aluminum nitride powder, China aluminum nitride powder manufacturers, suppliers, factory, Boron Nitride Continuous Casting Separation Ring, Boron Nitride Ceramic Precision Parts, Precision Ceramics, Hexagonal Boron Carbide, Boron Carbide Ceramic Disc
