氮对碳纤维石墨化的影响

Effect of Nitrogen Element in the Graphitization of Carbon Fibre

用元素分析、X射线衍射和拉曼光谱等手段对不同结构成分的石墨纤维进行表征,研究了石墨结构与纤维中氮的关系。结果表明:在高温石墨化过程中,随着氮的减少,石墨微晶堆叠厚度和宽度不断增大,纤维的晶区取向度和石墨化度提高。氮含量大于0.08%时,石墨片层中有氮原子的位置会扭曲变形,不利于石墨微晶的生长,石墨微晶大小、晶区取向度及石墨化度增长比较缓慢;当氮元素含量小于0.08%时,由氮引起的石墨片层缺陷很少,石墨微晶大小、晶区取向度及石墨化度的增长速率随氮的减少而大幅度提高。脱除氮原子虽然不能引起石墨片层的生长,但是含氮石墨片层生长的控制步骤。

Graphite fibers of Different nitrogen content was prepared.The element composition and crystallite structure of resulted fibers were investigated by means of element analysis,X-ray diffraction and Raman spectroscopy.The correlation between crystallite structure and nitrogen content of these fibers was investigated.The results show that,with decrease of nitrogen content,the graphite crystallite grow, crystallite orientation degree and graphitization degree increase.Crystallite size,crystallite orientation degree and graphitization degree increase slowly because of the distortion of the graphite layer with nitrogen atom when the fibers contain more than 0.08%nitrogen element.As nitrogen content is below 0.08%,the crystallite size,crystallite orientation degree and graphitization degree increase rapidly.Denitrogenation is control step of the growth of graphite crystallite containing nitrogen atom,but can＇t lead to the growth of graphite crystallite directly.