Underwater acoustic absorption of air-saturated open-celled silicon carbide foam

Silicon carbide (SiC) foam prepared by polymer pyrolysis combined with molten silicon reactive infiltration (MRI) process was experimentally studied for the first time regarding its underwater acoustic absorption coefficient (a) mainly over low and middle frequency range (200-4000 Hz). The relationship between a and the pore structure of SiC foam including pore size (d) and foam thickness (t) was studied. The results indicated that a increased with the decrease of pore size from 3 to 1 mm in most frequencies measured. a also increased with sample thickness at both low and medium frequency, but in general it was more sensitive to pore size than to sample thickness. The existing models built for air-filled porous material under atmospheric circumstance were not valid to describe the underwater acoustic absorption behavior of SiC foam materials. (C) 2015 Elsevier B.V. All rights reserved.