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

Abstract

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