原丝经过预氧化后仍保持原来的微原纤结构，纤维外部表层的石墨微晶较大，所含孔隙较少，内部的微晶较小且含有大量孔隙。
The ( graphite ) crystallites in the outer layer of the carbon fibers are large with few pores , while the inner crystallites are small with many pores .
微原纤维