关键词: 碳纤维, 氧化, 拉伸性能, 微观结构, 碳纤维, 氧化, 拉伸性能, 微观结构

Abstract: The changes of the properties and microstructure of carbon fibers made in our laboratory were studied in strong oxidation agents，including concentrated nitric acid and the mixtures of concentrated sulfuric acid and concentrated nitric acid. The results showed that when carbon fibers were oxidized by concentrated nitric acid，tensile strength of carbon fibers increased more than that of the untreated sample，meanwhile modulus had little change. When the carbon fibers are oxidized by the mixture，the strength and the modulus of carbon fibers decreased with the increase of oxidation time，and decreased rapidly with the increase of volume fraction of concentrated sulfuric acid. Results of XRD suggested that oxidation of concentrated nitric acid affect the microstructure size in the direction paralleled to fiber axis，and oxidation of concentrated sulfuric acid had effect on that in the lamellar stacking direction of carbon fibers.

Key words: carbon fibers, oxidation, tensile strength, microstructure, carbon fiber, oxidation, tensile strength, microstructure