Open‐cell porous sound‐absorbing ceramics prepared by a new procedure that combines foamed and templated methods.

Low‐grade nonmetal ore, mainly magmatic soil and tuff, was used to prepare porous sound‐absorbing ceramics. A new processing method that combines the foaming and templating methods was used to produce open‐cell porous ceramics. Silicon carbide and carbon powders were used as the foaming agent and template agent, respectively, and their effects on open‐cell preparation and sound‐absorption properties were also investigated. The results showed that sound‐absorption performance was closely related to the apparent porosity (H). Compared with either foaming or template methods, the new method incorporating both processes increased the sound‐absorption coefficient (α) and H by 51%‐258% and 69%‐728%, respectively. Optimum sound absorption of the ceramics, that is, α = 0.68, noise reduction coefficient (NRC) = 0.48, and H = 50.22%, were obtained at foaming agent contents (FACs) of 1.5 wt% and template agent contents (TACs) of 4 wt%. The Delany‐Bazley and Voronina models were selected to simulate the sound‐absorption coefficients and the latter one fitted well with our experimental results. [ABSTRACT FROM AUTHOR]