To optimize the preparation of Al2O3 aerogels,the sol-gel method was combined with supercriti-cal drying,using aluminum isopropoxide(AIP)as precursor,ethanol(EtOH)as solvent,and acetic acid(HAc)as catalyst.The effects of the ethanol addition[n(AIP)∶n(EtOH)∶n(H2O)∶n(HAc)=1∶8∶0.8∶2,1∶12∶0.8∶2,1∶16∶0.8∶2,and 1∶20∶0.8∶2]and acetic acid addition[n(AIP)∶n(EtOH)∶n(H2O)∶n(HAc)=1∶16∶0.8∶1,1∶16∶0.8∶2,1∶16∶0.8∶3,and 1∶16∶0.8∶4]on the pore structure and specific surface area of Al2O3 aerogels were studied.The results show that ethanol affects the pore structure of Al2O3 aerogels by affecting the condensation probability of Al—OH groups,and acetic acid affects the pore structure of Al2O3 aerogels by affecting the reaction rate;when n(AIP)∶n(EtOH)∶n(H2O):n(HAc)=1∶16∶0.8∶2,the Al2O3 aerogel has a porous microstructure,and its internal pore diameter is generally smaller than the average free path of air molecules,showing e×cellent thermal insulation characteristics,low density of 0.20 g·cm-3,and the specific surface area of 458,102,and 51 m2·g-1 at 25,1 000,and 1 200 ℃,respectively.
alumina aerogelthermal insulation materialspecific surface areapore size distribution
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