Preparation Of Alumina And Mullite Porous Ceramic Fiber Via Electrospinning

Alumina fibers and mullite fibers are known for excellent properties such as low density,high temperature oxidation resistance,chemical stability and other characteristics.They are widely used in industrial furnace,electronics,aerospace industry and so on.With the development of military and civilian technology,porous ceramic fibers with high specific surface area,adjustable pore diameter become the hot research topic area.In this study,alumina porous fibers and mullite porous fibers using uniaxial and coaxial electrostatic spinning were prepared.Firstly,the optimal parameters of alumina porous fibers prepared by uniaxial electrospinning are discussed.When the gel formed at 80°C,the gel concentration was 0.187 mol/L,the adding amount of CTAB and liquid paraffin were 0.37 g and 0.75 ml,respectively.The fiber forming process were investigated by DSC-TG,XRD,FTIR,SEM and BET analyses.Results show that after calcined at 600°C,the tiny hole in fiber form,when the calcination temperature was increased to 1000°C,γ-Al₂O₃ fiber formed,with heat treatment temperature increasing to 1200°C,α-Al₂O₃ porous fiber were obtained.Secondly,the process parameters of alumina porous fiber prepared by the coaxial electrospinning is studied.The internal flow rate was 0.1ml/h,external flow rate was 1.0ml/h and PVP dosage was 0.5g.The fiber forming process were investigated by DSCTG,XRD,FTIR,SEM and BET analyses.The results showed that the liquid paraffin and PVP partly decompose,and that the pores appear in the fibers calcined at 600 °C;After calcined at 800 °C,the number of pores increased,and fiber transformed into α-Al₂O₃.Additionally,the optimal process parameters of mullite porous fibers prepared by uniaxial and coaxial electrospinning methods were studied.It was difficult to prepare mullite porous fibers via uniaxial method using CTAB,liquid paraffin or P123 as phase separated agent;the internal flow rate was 0.1ml/h,external flow rate was 1.0ml/h,and PVP was 0.5g.The fiber forming process were investigated by DSC-TG,XRD,FTIR,SEM and BET analyses.The tiny hole appeared in fiber calcined at 600 °C;Mullite porous fibers with pore diameter in the range of 80¹20nm were obtained after 1200°C.