N2 - Recently, a new class of ceramic foams with porosity levels up to 90% has been developed as a result of the association of the gelcasting process and aeration of the ceramic suspension. This paper presents and discusses original results advertising sound absorbing capabilities of such foams. The authors man- ufactured three types of alumina foams in order to investigate three porosity levels, namely: 72, 88, and 90%. The microstructure of foams was examined and typical dimensions and average sizes of cells (pores) and cell-linking windows were found for each porosity case. Then, the acoustic absorption coefficient was measured in a wide frequency range for several samples of various thickness cut out from the foams. The results were discussed and compared with the acoustic absorption of typical polyurethane foams proving that the alumina foams with high porosity of 88-90% have excellent sound absorbing properties competitive with the quality of sound absorbing PU foams of higher porosity. L1 - http://journals.pan.pl/Content/101554/PDF/07_paper.pdf L2 - http://journals.pan.pl/Content/101554 PY - 2013 IS - No 4 EP - 502 DO - 10.2478/aoa-2013-0059 KW - sound absorption KW - porous materials KW - alumina foams A1 - Zieliński, Tomasz G. A1 - Potoczek, Marek A1 - Śliwa, Romana E. A1 - Nowak, Łukasz J. PB - Polish Academy of Sciences, Institute of Fundamental Technological Research, Committee on Acoustics VL - vol. 38 DA - 2013 T1 - Acoustic Absorption of a New Class of Alumina Foams with Various High-Porosity Levels SP - 495 UR - http://journals.pan.pl/dlibra/publication/edition/101554 T2 - Archives of Acoustics