RATE AND HEAT OF VAPORIZATION OF GRAPHITE ABOVE 3000 DEGREES K

The rate of vaporization of graphite filaments has been measured from 2500 to 3400°K in vacuum and in He by pulse heating techniques. At 3400°K, the rate of vaporization was sufficiently high that a direct determination of the heat of vaporization could be obtained. The experimental results have been correlated with thermodynamic data obtained at lower temperatures on graphite and its vapor species; the predominance of C2 in vaporizing graphite is shown to satisfy the experimental results. The specific surface area of the filaments was measured and interpreted.