含钽炭基复合材料前驱体的制备及表征

Tantalum-containing pitch as a carbon precursor was synthesized by an in situ liquid phase reaction between coal tar pitch and tantalum pentachloride. The dispersion, chemical state and transformation of tantalum during carbonization and graphitization were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction measurements. Also, the effects of the amount of tantalum pentachloride and reaction time on the softening point of the pitch were investigated. Results showed that the tantalum particles were dispersed homogeneously in the pitch precursor with sizes in the range of 20-50nm. The tantalum particles mainly existed in the form of δ-Ta2O5 when the reaction temperature was 420℃. By further heat treatment, δ-Ta2O5 was transformed into β-Ta2O5 at 900℃. Β-Ta2O5 and TaC co-existed at 1200℃. At 2800℃, all the tantalum was transformed into TaC.