High-performance aluminum nitride made by Vat photopolymerization through optimization of resin refractive index and plasticizer content

In this study, we evaluated the effects of three resins with different refractive index on the viscosity and curing behavior of aluminum nitride (AlN) ceramic suspensions. Our findings indicate that the viscosity of the AlN suspensions increased with the concentration of polyethylene glycol o-phenylphenyl ether acrylate (OPPEA). Conversely, the viscosity decreased with increasing concentrations of cyclic trimethylolpropane formal acrylate (CTFA) and ethylene glycol phenyl ether acrylate (PHEA). Regarding the curing behavior, the AlN ceramic suspension prepared with OPPEA exhibited the largest cure depth and excess width, whereas the suspension prepared with CTFA had the lowest cure depth and excess width. Further analysis of the sensitivity and critical energy revealed that the suspension containing OPPEA demonstrated the highest sensitivity in the vertical direction and the lowest sensitivity in the horizontal direction. This implies that the smallest critical energy is in the vertical direction, and the largest critical energy is in the horizontal direction. Additionally, an increase in the content of the plasticizer dibutyl phthalate (DBP) was beneficial for reducing cracks in the AlN ceramic debinding bodies. Finally, high-performance AlN ceramics were produced, exhibiting a relative density exceeding 98 %, a bending strength of 470.39 ± 6.5 MPa, and a thermal conductivity of 163.45 W/m·K.