Research On Preparation And Sound Absorption Properties Of Novel Foam Aluminum

Foam aluminum is a new type of structural and functional material,which has unique structural characteristics determine that has many excellent properties and widely used in sound field.Firstly,this paper shows a new technology for the preparation of porous aluminum materials with CaO granules as a infiltrating agent(This method was authorized national patent,and the patent application number 201610242168).Three new kinds of aluminum foam materials with different pore structure size(0.90~1.43 mm,1.43~2.00 mm,2.00~2.50mm)were prepared with tailor-made low-pressure infiltration device.Then pay attention to the defects appeared in the process of preparation and deal with them by analyzing,combined with the preparation quality in the process and parameters to adjust and find optimum technique parameters which could produce accepted foamed aluminum.Under the conditions that the preheat temperature 630?,580?and 550?;the infiltrated temperature 720 ?,710 ? and 700 ?;the infiltrated pressure 0.05 MPa,0.04 MPa and0.03MPa;the dwell time 45 s,30s and 25 s,the new type of foam aluminum with different pore size can be prepared respectively.Secondly,CaO granules removal process using the designed automatic removal equipment,aimed at removing process parameters such as temperature,stirring rate,the concentration to achieve accurate control,especially Removing efficient,removing effect and the materials structural can be ensured by control the temperature 50?,stirring rate100r/min,concentration 33%.Finally,the sound absorption of three new kind samples was tested by transfer function method.Test results indicated that:(1)Samples with three apertures all have good sound absorption performance in the high-frequency range(1600 ~ 6200 Hz),and the sound absorption coefficients of the three aperture samples with the thickness of 16 mm can beyond 0.8 in the range of 4000-4400 Hz.(2)Three kinds samples can adjust the optimal sound absorption frequency range of high-frequency band by changing the thickness.By increasing the thickness,the lowfrequency absorption coefficient can be increased.The change of frequency range has little effect on the peak absorption coefficient in the low-frequency.(3)In the low frequency range(250 ~ 1600Hz),the foamed aluminum sample with the aperture of 0.90 ~ 1.43 mm has the best sound absorption performance,and the soundabsorption coefficient of the sample with the thickness of 24 mm can beyond 0.7 in the frequency range of 1450 ~ 1500 Hz.