The Analysis And Research Of Sintered Fecral Fibrous Porous Materials' Performance In Sound Absorption

Sintered FeCrAl fibrous porous materials used in sound absorption field is a new study orientation in metal fibrous technology area. Sintered FeCrAl fibrous porous materials have the characteristics of FeCrAl alloy and porous structure, and they possess lots of special advantages, such as high temperature resistance, anti-oxidation, hot corrosion resistant, good performance of flow impact resistant, long service life, easily forming, higher effective porosity, stable performance, designable of the structure, above all, sintered FeCrAl fibrous porous materials have stable and excellent properties to absorb the high intensity noise. Therefore, sintered FeCrAl fibrous porous materials can be used as high temperature liners in the turbofan cavity of aero-engine. Compared with other materials, sintered FeCrAl fibrous porous materials have excellent performance in sound absorption. It is suitable for absorbing high intense noise in special environment of space and defense area.In this dissertation, sintered FeCrAl fibrous porous materials with different porosity were prepared by using vacuum sintering technology. Parameters of pore structure were effectively controlled during this process and component volatilization in FeCrAl fibrous porous materials can be also avoided. This paper aimed at studing sound absorption performance of sintered FeCrAl fibrous porous materials. The parameters of acoustics character and sound absorption performance were analyzed in detail. The results indicated that porosity, thickness and cavity play an important role in sound absorption under ordinary acoustic pressure and high sound intensity conditions. In order to improve the sound absorption characteristics for sintered FeCrAl fibrous porous materials under low and middle frequency, the composite structure with 2-3 layers were redesigned. The results show that the arrangement of composite structure in porosity order from high to low is the best. The thicker the every layer thickness of the structure is, the better the sound absorption performance is. The sound absorption characteristics of monolayer and gradient composite structure under ordinary acoustic pressure and high sound intensity conditions (100-140dB) show that the sound absorption characteristic was constant with the change of acoustic pressure levels. It shows that sintered FeCrAl fibrous porous materials have good ability to absorb high intensity noise. The research of this dissertation is funded by National 973 of China (project No. 2006CB601200).