The capillary and thermal performance of the porous silicon nitride ceramics with nearly spherical pore structure

Abstract

AbstractThe 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.