用X射线小角散射法研究裂解温度对碳化硅纤维微孔孔径分布的影响

EFFECT OF PYROLYSIS TEMPERATURE ON MICROPORE SIZE DISTRIBUTION IN SILICON CARBIDE FIBERS BY THE SMALL ANGLE X-RAY SCATTERING

用X射线小角散射技术研究了600,700,900,1200,1300℃制备的碳化硅(SiC)纤维中在0.5～20nm范围的孔径分布和孔体积分布。结果表明:SiC纤维中的孔不具有明锐的界面,界面的明锐程度会随着制备温度有规律地变化。SiC纤维中的孔径分布并不连续,并且随制备温度不同孔径分布明显变化,其变化与聚碳硅烷预氧化纤维的裂解过程有关。SiC纤维中,孔半径在0.5～2nm范围的微孔体积在所研究的0.5～20nm的微孔中所占比例较大,超过30%。

Silicon carbide （SIC） fibers, pyrolysed at 600, 700, 900, 1 200 ℃, and 1 300 ℃ were synthesized, and micropore size distribution within 0.5-20 nm in fibers was studied using the small angle X-ray scattering technique. It is found that the interface of pores in SiC fibers is not sharp and the sharpness of the interface changes with pyrolysis temperature; the pore size distribution in SiC fibers is not continous and changes obviously with pyrolysis temperature, attribute to the pyrolysis process of cured polycarbosilane （PCS） fibers; the pores of 0.5-2 nm in radius have high volume ratio within the studied pores of 0.5-20 nm in radius, above 30%.