Preparation And Properties Of Novel Open Cellular Foam Ceramic Materials

Foam ceramics with interconnected pore structure have broad application prospects in gas adsorption purification,sound absorption and noise reduction,and catalyst carriers.In view of the fact that most of the current foam ceramics are closed-cell structures and have low porosity and low specific surface area,this paper is based on particle-stabilized foams,using surfactants for ceramic ceramic components(hollow spheres,ceramic powders,nano-alumina and Aluminum-silica sol),modified to prepare oxide foam ceramics;and innovatively proposed the use of volatile oily substances as pore-forming agent combined with particle-stabilized foam technology to prepare high specific surface area alumina open-cell ceramics,the main achievements as follows:The porous structure diatomaceous earth powder and mesoporous silica hollow spheres were hydrophobized with a long-chain surfactant cetyltrimethylammonium bromide(CTAB)to prepare light with uniform macroscopic pores and porous structure.A diatomaceous earth foam ceramic having a bulk density of 0.225 m~3/g and a specific surface area of 5.20 m~2/g;and a three-dimensional foam structure and a high specific surface area silica foam ceramic.The long-chain surfactant sodium dodecyl sulfate(SDS)is used to modify the submicron-sized powders of cerium oxide,aluminum oxide and zirconium oxide;the nano-sol particles of aluminum sol and aluminum-silica sol are respectively modified to be hydrophobic;The foaming compound is added with a pore-forming agent to prepare an ultra-stable foam,and the open-cell foam ceramic is prepared by high-temperature sintering.The experiment found that the porosity decreased with the increase of solid content,while the compressive strength showed the opposite trend.With the increase of SDS,the expansion ratio increased from 2 to 3.Afterwards,it tends to be stable;as the sintering temperature increases,the porosity of the sample decreases,the particle size increases,and the linear shrinkage and compressive strength increase.For the choice of pore-forming agent,the pore size and morphology formed by different pore-forming agents are different,and the pore morphology can be controlled according to the choice of pore-forming agent.Innovatively using the particle-stabilized foam emulsion to prepare open-cell foam ceramics,using volatile oil phase materials as pore-forming agent,and sub-micron alumina powder and sol nanoparticles as raw materials,successfully preparing foam ceramics with open-cell structure.The alumina foam ceramic prepared by the foam emulsion has a porosity of 90.3%and a compressive strength of 5.9 MPa.The aluminum sol foam ceramic has a porosity of 89.8%and a compressive strength of 7.8 MPa.Differences in the amount of n-octane added can result in differences in open cell structure and specific surface area.When the amount of n-octane added is 20mL,the specific surface area of the sample material is as high as 54.1849m~2/g.When the n-octane is continuously increased to 30mL,the specific surface area of the sample is reduced to5.6785m~2/g,but the open porosity and opening of the material.The aperture will increase.