Effect of Yttrium Nitrate Coating on the Vat Photopolymerization Forming Process and Sintering Properties of Aluminum Nitride Ceramics

In this study, a ball-milling method was successfully used to coat yttrium nitrate on the surface of aluminum nitride (AlN) powder and the effects of yttrium nitrate content on the AlN powder particle size, viscosity and curing behavior of the AlN suspension, and performance and microstructure of the sintered AlN bodies were investigated. The results indicated that the AlN powder surface coating significantly reduced the viscosity of the suspension and enhanced the cure depth while increasing the powder particle size, which in turn reduced the stability of the suspension. By studying the performance of sintered bodies, it was found that as the yttrium nitrate content increased, the AlN thermal conductivity and flexural strength initially increased and then decreased. Microstructural analysis results revealed that the second phase in samples with 9.23 and 14.49wt% yttrium nitrate exhibited an island-like distribution, whereas in samples with 19.18wt% yttrium nitrate, the second phase exhibited a continuous distribution. Finally, the heat-dissipation performance of AlN components with different structures was also studied, and testing was conducted on the driving chip of a 3D printing device. The results indicated that complex-structured AlN ceramic components exhibited an excellent heat-dissipation performance.