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 (Si3N4) 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 Si3N4 foams was only 2-3 µm and the pores in the Si3N4 foams fabricated here exhibited polyhedral shapes. Thermal conductivities of these Si3N4 foams ranged from 2.427 W m−1 K−1 to 3.154 W m−1 K−1, whereas compressive strengths of these Si3N4 foams are in the range from 12.85 MPa to 19.99 MPa. Moreover, compressive load-displacement curves of the Si3N4 foams generally exhibit cellular behavior.