Preparation of high porous silicon nitride foams with ultra-thin walls and excellent mechanical performance for heat exchanger application by using a protein foaming method

Ceramic foam with excellent mechanical performance, high thermal conductivity and high surface area-to-volume ratio is thought to have great potential in heat exchanger application. In this study, silicon nitride (Si 3 N 4 ) foams with ultrathin cell walls were prepared by using a protein foaming method via increasing the air fraction of foamed slurry. Cell thickness of these Si 3 N 4 foams was only 2–3   µm and the pores in the Si 3 N 4 foams fabricated here exhibited polyhedral shapes. Thermal conductivities of these Si 3 N 4 foams ranged from 2.427   W   m −1   K −1 to 3.154   W   m −1   K −1 , whereas compressive strengths of these Si 3 N 4 foams are in the range from 12.85   MPa to 19.99   MPa. Moreover, compressive load–displacement curves of the Si 3 N 4 foams generally exhibit cellular behavior.