基于3D打印构筑的高面间热导率氮化硼陶瓷的制备.

Boron nitride（BN） ceramics have excellent properties such as high aspect ratio, high temperature resistance, high thermal conductivity and electrical insulation, widely used in electronic information, aerospace, metallurgy, machinery and other fields. 3D printing technology has low cost and time-saving compared with traditional processing methods, and is an important molding technology for the preparation of ceramic parts with complex three-dimensional structure. To this end, in this paper, based on the self-developed pneumatic new direct-write 3D printing material forming platform, ceramic slurries with different BN contents were prepared using BN and polyvinyl alcohol（PVA） as raw materials and binder, and ceramic preforms with different 3D structures were designed and prepared using the layer-by-layer stacking principle. By changing the rheological properties of the slurries, the BN 2D nanosheets were realized in the printing process under the shear. By changing the rheological properties of the slurry, the orientation of BN 2D nanosheets under the action of shear force was achieved during the printing process, and ceramic materials with high interplanar thermal conductivity were obtained. The effect of BN content on the molding quality of the ceramic parts was investigated, and the structure and microscopic morphology of the printed ceramic materials were characterized by XRD and SEM. The results show that the BN/PVA 85 slurry has good shear thinning and viscoelastic properties, and the yield stress in the linear viscoelastic region reaches 240 Pa, which is suitable for direct-writing 3D printing technology. the increased horizontal orientation of BN inside the part contributes to the enhanced interfacial thermal conductivity of the ceramic material, where the interfacial thermal conductivity of the BN/PVA 85 ceramic part is about 4.3 W/（m·K）. [ABSTRACT FROM AUTHOR]