| 摘要 |
PURPOSE:To obtain high silencing efficiency in a wide frequency band from a low frequency to a high frequency by combining specific double-layered materials and aluminum base materials having many bored pores. CONSTITUTION:A double-layered material 12 constituted by forming a film 11 having the micropores consisting of ceramic powder by plasma thermal spraying on the surface of the aluminum base material 10 and the aluminum base material 13 having the many bored pores are joined in multiple layers. The silencing materials A, B formed by laminating and welding the aluminum base materials 13, 13a having the pores of respectively different diameters on the double-layered materials 12, 12a are further superposed on each other and are welded to obtain the double-layered silencing material. The microporous ceramic films 11 and 11 a are constituted so as to respectively vary the micropore sizes thereof, by which the sound waves of different short wavelengths are absorbed by these micoporous ceramic film layers. The sound waves of different long wavelengths are absorbed by the aluminum base materials 13, 13a having the pores of respectively different diameters and, therefore, the effect as the silencing material is exhibited. |
