Abstract: The anti-oxidation performance of carbon fiber in high temperature atmosphere was increased greatly after it was treated with boron agents.It was shown by means of TGA,SEM,XPS and WAXD that the treatment elevated the decomposition point above 268℃, and increased the average oxidation activation energy doubly,from 98.6kJ/mol of the untreated fiber to 220.3kJ/mol of the treated fiber,with the first order of the fiber oxidation reaction under non-isothermal conditions,and increased the life-time many times.During the process,however,the mechanical properties developed slightly.

Key words: Carbon fiber, Anti-oxidation, Boron compound