Why is Machining Aluminum Nitride Ceramics Challenging?
Aluminum nitride ceramics , composed mainly of aluminum nitride, possess remarkable properties such as high thermal conductivity, excellent insulation, and low dielectric constant. The crystal structure of aluminum nitride consists of tetrahedral units forming a covalent-bonded compound, exhibiting a spinel-type structure within the hexagonal crystal system. With a chemical composition of 65.81% aluminum and 34.19% nitrogen, and a density of 3.261g/cm3, aluminum nitride ceramics appear white or gray-white, with single crystals being transparent and colorless. These ceramics boast a sublimation decomposition temperature of 2450°C under standard pressure, making them ideal for high-temperature applications. Additionally, their coefficient of thermal expansion ranges from 4.0 to 6.0 * 10^-6/°C, and their polycrystalline form exhibits a thermal conductivity of up to 260W/(m·K), surpassing that of aluminum oxide by 5-8 times, thus demonstrating excellent resistance to thermal shock up to 22...