Ceramic Foam Prepared By Protein Foaming Method And Its Performance

Due to their special pore structure, chemical stability and outstanding hightemperature, ceramic foams have great potentials in the application of catalystsupports, biomaterials, hot gas filters and sound-absorbing materials. Based onthe demand on sound-absorbing materials used in high temperature, Al₂O₃, ZrO₂,Si₃N₄ceramic foams were prepared via protein foaming method and their thermalinsulation and sound absorption performance were investigated.Firstly, the Al₂O₃ceramic foam was prepared via protein foaming method.The amount of D3005ceramic slurry dispersant added and the protein burnoutprocess were studied. When the dispersant was added in0.6ml/100g Al₂O₃, theslurry had the lowest viscosity. The protein burnout process was set for1℃/minheating to600℃and incubated for1hour.Subsequently, the effect of sintering additive, sintering temperature andmixture of different kinds of proteins on Al₂O₃ceramic foam were investigated.Their porosity, density and compressive strength were tested. Results showed that:Both adding sintering additive and enhancing sintering temperature can improvethe physical properties of the Al₂O₃ceramic foam. The mixture of egg white andcollagen which are in two different structures can integrate the advantages ofthem.This paper also studied the preparation process and the physical propertiesof different ceramic foam. The porosity, density and compressive strength ofAl₂O₃, ZrO₂, Si₃N₄ceramic foams were compared. The investigation revealedthat Si₃N₄ceramic foam had better performances than Al₂O₃ceramic foam andZrO₂ceramic foam in ether term of macro or micro, which had larger porosity,smaller density and better compressive strength, especially at lower solidcontents.The application performances of different ceramic foams were studded atlast. The thermal conductivity and sound absorption coefficient of Al₂O₃, Si₃N₄,ZrO₂ceramic foams were tested. Results showed that all kinds of ceramic foamhad good thermal insulation performance and their thermal conductivity increased with the decrease of porosity. Wherein, Si₃N₄ceramic foam had lowerthermal conductivity than Al₂O₃ceramic foam and ZrO₂ceramic foam. At20vol%solid content, its thermal conductivity was as low as0.13W/（m·k）. Thesound absorption coefficient of ceramic foam was less volatile with theincreasing of sound frequency. The ceramic foam with higher porosity had bettersound absorption performance. Among the three kinds of ceramic foam, Si₃N₄ceramic foam had generally higher sound absorption coefficient than Al₂O₃ceramic foam and ZrO₂ceramic foam, whose highest sound absorptioncoefficient can be up to0.73.