Noise Absorption Properties of Nanoporous Ceramic Silica Grains

Abstract— The possibility of using the grains formed from nanosized silica powders as materials reducing acoustic vibrations was studied. Grains with sizes from several hundreds of micrometers to several millimeters were obtained by drying from aqueous suspensions of nanopowders and crushing the dry compacts with further classification by sizes. The resulting materials are characterized by open porosity with nanosized pores, whose volume attains more than 50% from the volume of grains. They were further used as an independent noise-absorbing material layer and as a modifier of foam polymer materials used, in particular, in cars. It has been shown that, for grained nanoporous materials based on nanoparticles, it is possible to find optimal configurations depending on the required band of suppressing the frequencies of acoustic vibrations. The use of a bulk layer from such a material with a thickness of 10 mm increases the noise absorption coefficient of a substrate to values above 0.5 for the frequencies from 400 to 1600 Hz. The results may be useful for the construction of new theoretical approaches in continuum mechanics, in particular, in acoustic physics.