Sound absorption properties of ceramic hollow sphere structures with micro-sized open cell

Porous structure with micro-sized open cell was tailored for the sound absorption, and ceramic hollow sphere structures (CHSS) were prepared by low temperature pre-bonding and curing process. Micro-sized open cells of CHSS, which demonstrated normal/bimodal distribution, were mainly observed in the interstitial gaps of fly ashes. The CHSS with micro-sized open cells demonstrated a broadband sound absorption above 500 Hz, and its acoustics behavior was affected significantly by the porous structure. The calculated values of sound absorption based on the Pride-Allard model demonstrated similar trends as experimental results with the increase of frequency.