Effect of particle size on rheology, curing kinetics, and corresponding mechanical and thermal properties of aluminum nitride (AlN) ceramic by digital light processing (DLP)-based vat photopolymerization

In this work, the influence of AlN particle size (250 nm, 1.2 mu m, and 5 mu m) on the curing behavior, stability and viscosity of ceramic suspensions was evaluated. It was revealed that an increase in the particle size of AlN powders reduced the stability and viscosity of the suspension. For curing behavior, the ceramic suspension prepared with 250 nm AlN powder exhibited the smallest curing depth and excess width, whereas the 5-mu m ceramic suspension had the largest curing depth. The analysis of the scattering length revealed that a decrease in AlN powder particle size reduced the scattering length. After sintering, both the 250-nm and 1.2-mu m samples could be sintered densely at temperatures more than 1800 degrees C with the relative density greater than 99%. Finally, following a 5 h sintering at 1850 degrees C, the 250-nm and 1.2-mu m samples obtained thermal conductivities of 171 and 174 W/mK, respectively.