B-Si掺杂沥青基炭材料的制备及其氧化行为研究

On the Preparation and Oxidation Behavior of B-Si Doped Pitch Based on Carbon Materials

以煤沥青甲苯可溶组分、聚碳硅烷和吡啶硼烷为原料合成了B-Si掺杂沥青,B-Si掺杂沥青经炭化处理得到了B-Si掺杂炭材料。研究结果表明,炭化温度对B-Si掺杂炭材料的物相组成、微观结构和抗氧化性能有重要影响。1200℃炭化处理得到的B-Si掺杂炭材料中含有无定形B4C和Si C微晶,在空气气氛中容易快速氧化形成B2O3和Si O2,Si O2可以进一步在B2O3中溶解形成固溶体,从而提高炭材料表面形成的氧化膜的热稳定性。与在800℃、1000℃、1400℃和1600℃炭化得到的B-Si掺杂炭材料相比,在相同氧化条件下,1200℃炭化得到的B-Si掺杂炭材料显示了较好的抗氧化性能,它在1000℃空气气氛中氧化1 h,失重率仅为5.7 wt%,比其它B-Si掺杂炭材料的失重率小很多。

Pitch doped with B and Si was prepared using toluene soluble fraction of coal tar pitch, polycarbosilane and pyridine borane as raw materials. The B and Si doped carbon materials was obtained by carbonization of the doped pitches at different temperatures. The results indicate that the carbonization temperature has a significant influence on the phase composition, microstructure and oxidation resistance of B and Si carbon materials. B and Si doped carbon materials obtained by carbonization at 1200 ℃ contains amorphous B4 C and Si C crystallite, which could be oxidized quickly to form B2O3 and Si O2 in air. The formed Si O2 further dissolves in B2O3 to form a solid solution, which improves the thermal stability of the oxide coating formed on the surface of the B and Si doped carbon materials. Among the B and Si doped carbon materials obtained by carbonization at different temperatures, the B and Si carbon materials obtained by carbonization at 1200 ℃ shows good oxidation resistance under the same oxidation condition. It loses 5.7 wt% of its initial weight after oxidation at 1000 ℃ in air for 1h, much less than the weight loss of other B and Si carbon materials.