Vat photopolymerization of high-strength aluminum nitride ceramics through nitrate additives coating

Abstract

Aluminum nitride ceramics are widely used in electronic devices, but their applications are hindered by relatively low mechanical strength. A multicomponent sintering additive approach was employed to address it. Yttrium hexahydrate nitrate, samarium hexahydrate nitrate, and scandium monohydrate nitrate were incorporated to develop AlN ceramics with mechanical properties via vat photopolymerization comparable to those of Si₃N₄ ceramics. The influence of different nitrate contents on the viscosity and curing behavior of AlN suspensions was investigated. The results show that curing performance of AlN suspensions used for printing was optimized. Furthermore, dense AlN ceramics were fabricated through pressureless sintering at 1800 °C for 4 hours. The samples incorporating ternary sintering additives exhibited the highest comprehensive performance with a flexural strength and thermal conductivity of 616.6 MPa and 74.09 W/(m·k). This represents a significant advancement in the development of digital light processing-printed AlN ceramics with mechanical performance levels approaching those of Si₃N₄ ceramics.