The capillary and thermal performance of porous Si₃N₄ ceramics with nearly spherical pore structure has been investigated by altering the addition and diameter of pore-forming agent polymethyl methacrylate (PMMA) in this work. An exponential model is used to evaluate the liquid uptake capacity of porous Si₃N₄ ceramics. Porous Si₃N₄ ceramics fabricated by 5 μm PMMA with 40 wt.% addition possess the lowest capillary time constant and show the best capillary performance owing to the perfect balance between friction resistance and capillary force. The thermal conductivity of porous Si₃N₄ ceramics is significantly impacted by their porosity. Alexander model with an exponent of .96 is suitable for predicting the thermal conductivity of porous Si₃N₄ ceramics due to its R-squared up to .99. Moreover, with the addition and diameter of PMMA decrease, the flexural strength of porous Si₃N₄ ceramics increases. These results support the application of porous Si₃N₄ ceramics in the field of mass and heat transfer.

中文翻译：

---

近球形孔结构多孔氮化硅陶瓷的毛细管性能和热性能

在这项工作中，通过改变造孔剂聚甲基丙烯酸甲酯 (PMMA) 的添加量和直径，研究了具有近球形孔结构的多孔Si ₃ N ₄陶瓷的毛细管和热性能。指数模型用于评估多孔 Si ₃ N ₄陶瓷的液体吸收能力。由 5 μm PMMA 添加 40 wt.% 制备的多孔 Si ₃ N ₄陶瓷具有最低的毛细管时间常数，并且由于摩擦阻力和毛细管力之间的完美平衡而表现出最佳的毛细管性能。_{多孔Si 3} N ₄的热导率陶瓷受其孔隙率的显着影响。指数为 0.96 的亚历山大模型适用于预测多孔 Si ₃ N ₄陶瓷的热导率，因为其R平方高达 0.99。_{此外，随着PMMA的添加量和直径的减小，多孔Si 3} N ₄陶瓷的弯曲强度增加。_{这些结果支持了多孔Si 3} N ₄陶瓷在传质传热领域的应用。