Fabrication and application of metal fiber absorbers and metal foams
There exist different methods for the fabrication of metal fibers, for instance cutting or melting extraction. The latter one can be considered as a particularly low-cost method. By sintering of the metal fiber packages, the solidness can be further increased.
Metal foams can be considered as an alternative for applying metal fibre absorbers. The airflow resistance and thus the spectral sound absorption coefficient can be optimized by varying the pore size and the pore number per volume unit respectively.
In the case of a very high porosity, the metal foam loses its sound absorbing properties. However, by applying a suitable metal alloy possessing a high heat-resistivity in combination with an additional coating, such metal foams can be efficiently installed as a catalytic structure. They can be streamed by an airflow but causing only a low pressure drop.