The effect of diffusion and bulk gas flow on the thermal oxidation of porous carbons—II. Diffusional effects in graphite at high temperatures

Penetration depth and transient oxidation of graphite by oxygen and water vapor

“…Experiments conducted on British nuclear graphites [3][4][5], lead to a tentative form for the effective diffusivity,…”

“…The numerical value for activation energy was determined by empirical fit of oxidation rate data as reported in [8]. D gas for H 2 O in He was taken as 2.74 cm 2 /s at 673 K [5]. As above, a T 1.5 temperature dependency of D gas was assumed.…”

Note on Graphite Oxidation by Oxygen and Moisture

“…Between 2% and 3% burnoff, there was gradual rise in m from 0.01 to about 0.013. Hawtin and Gibson (1966) measured D eff in oxidized "Pile A" British graphite in the temperature range 550 -675°C. O 2 concentrations ranged from 2.5 -20.8%.…”

“…Table 3 shows the computed results, assuming the unoxidized density to be 1.8 g/cm 3 . (Hawtin and Gibson, 1966) % Burnoff m x 100 0 0.4 5 0.5 10 1 15 1.6 20 2.4…”

Effective gaseous diffusion coefficients of select ultra-fine, super-fine and medium grain nuclear graphite

“…The limited studies that do exist are mostly from U.K researchers in the 1960s. These studies primarily investigated grades using large grain sizes for filler material [15][16][17][18][19][20][21][22][23][24][25] and are considerably different from current nuclear graphite grades of interest. In order to predict the effects of damage and degradation from oxidation, one must know how deep the oxidizing reactants penetrate into pore structures as well as how much oxidation has occurred locally within an exposed pore structure.…”