Preparation and Sound Absorption Property of Alumina Ceramic Foam for Sound Insulation and Noise Reduction in Transformers

Alumina ceramic foams for sound insulation and noise reduction in transformers were prepared through gel foaming method. The optimum additional amounts of gelling agent and foaming agent were obtained through experiment. The effects of thickness of samples and cavity in the rear on sound absorption property were discussed. Results show that, when the additive amounts of foaming agent and gelling agent both are 1.00wt%, the porosity, average pore diameter, flexural strength and compressive strength of the obtained ceramic foam were 75.2%, 150 μm, 8.13 MPa and 5.41 MPa, respectively. When the thickness of the sample was 15 mm and cavity in the rear of the sample was 20 mm, the maximum sound absorption coefficient of the ceramic foam was 0.8, the sound absorption coefficient in the frequency range of 100-500 Hz was 0.12-0.65.