Oxidation Properties of Vapor Grown Graphite Fibers

摘要

The oxidation behavior of a novel carbon fiber has been determined using a Thermogravimetric Analysis (TGA) technique in flowing air (52 ml/min) at temperatures ranging from 500 to 1100 C. The oxidation rates of three preparations of vapor grown carbon fiber (VGCF) are compared to PAN fiber. At 500 C, the oxidation rate of the as-grown fiber is comparable to PAN fiber, and the oxidation rate of the as-grown carbon fiber is higher than that of the PAN fiber at all temperatures above 500 C. The oxidation behavior of annealed VGCF is very much different from that of the as-grown fibers. There is essentially no oxidation observed for the annealed fiber at 500 C in air. The oxidation rate of the annealed fiber at 700 - 1100 C is much lower than that of the as-grown fiber. Boronated VGCF shows even higher oxidation resistance compared to PAN fiber, as-grown VGCF, and annealed VGCF at 500 C to 700 C. Experimental results demonstrate the feasibility of VGCF-reinforced composites for operating temperatures up to 900 K.