Influences of compression ratios on sound absorption performance of porous nickel- iron alloy

Abstract

The improvement of sound absorption performance of porous metal is a focus of research in the field of noise reduction. Influences of compression ratios on sound absorption performance of a porous nickel–iron (Ni–Fe) alloy were investigated. The samples were compressed with ratios from 10% to 80% at an interval of 10%. Based on the standing wave method, sound absorption coefficients of compressed samples with different thicknesses were obtained. It could be found that with the same compression ratio, sound absorption performance was improved with the increase of thickness. Based on the modified Johnson–Allard model with a correction factor, the sound absorption coefficient of the porous Ni–Fe with a thickness of 20 mm for different compression ratios was derived, whose aim was to quantificationally analyze influences of the compression ratio. The results indicated that the sample with a compression ratio of 70% exhibited optimal sound absorption performance, and its average sound absorption coefficient reached 88.97% in a frequency range of 1000–6000 Hz. Meanwhile, the section morphologies of compressed samples were investigated by a scanning electron microscope, which studied the sound absorption performance by analyzing structures of the porous Ni–Fe samples with different compression ratios. The obtained achievements will promote the application of the porous Ni–Fe alloy in the field of acoustics.