Structure evolution and thermal stability of La_2O_3-doped mullite fibers via sol-gel method  

作　　者：王炜 翁端 吴晓东 

机构地区：[1]State Key Laboratory of New Ceramics&Fine Process,Department of Materials Science and Engineering,Tsinghua University [2]The Second Artillery NCO Academy of PLA

出　　处：《Journal of Rare Earths》2012年第2期175-180,共6页稀土学报（英文版）

基　　金：Project supported by the Ministry of Science and Technology of China (2009AA064801)

摘　　要：The lanthana-doped mullite fibers were prepared via a sol-gel method from the aluminum isopropoxide-aluminum nitrate-tetraethyl orthosilicate system. The structure evolution and thermal stability of the mullite fibers were investigated by means of X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectroscopy, differential scanning calorimetry （DSC）, scanning electron microscopy （SEM） and trans-mission electron microscopy （TEM）. The results showed that the fibers obtained after calcination at 1000℃ was in the form of Al2O3-rich mullite, which tended to transform to stoichiometric mullite with the lanthana content increasing. The lattice parameter a exhibited a decline trend with the lanthana content increasing, while b showed an upward tendency. Correspondingly, the redshift of Si-O-Si bond from 1255 to 1245 cm-1 was observed. The grain growth was inhibited for the doped fibers, among which the 5% La2O3-doped sample presented a mini-mum crystallite size （17.2 nm） after calcination at 1000 ℃ for 1 h.The lanthana-doped mullite fibers were prepared via a sol-gel method from the aluminum isopropoxide-aluminum nitrate-tetraethyl orthosilicate system. The structure evolution and thermal stability of the mullite fibers were investigated by means of X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectroscopy, differential scanning calorimetry （DSC）, scanning electron microscopy （SEM） and trans-mission electron microscopy （TEM）. The results showed that the fibers obtained after calcination at 1000℃ was in the form of Al2O3-rich mullite, which tended to transform to stoichiometric mullite with the lanthana content increasing. The lattice parameter a exhibited a decline trend with the lanthana content increasing, while b showed an upward tendency. Correspondingly, the redshift of Si-O-Si bond from 1255 to 1245 cm-1 was observed. The grain growth was inhibited for the doped fibers, among which the 5% La2O3-doped sample presented a mini-mum crystallite size （17.2 nm） after calcination at 1000 ℃ for 1 h.

关 键 词：mullite fibers lanthana doping phase transformation grain growth rare earths 

分 类 号：TQ343[化学工程—化纤工业]