“…Indeed, there are different quantities of residual carbon content in the specimens, which accounted for the deviation of the slope from the value predicted by the chemical reaction leading to the product of CO. The other factor that led to such a deviation was that the residual carbon contents for the specimens thermally treated in N 2 -3%H 2 were lower than those counterparts in N 2 , caused by the reaction between carbon and hydrogen (Trefilov et al, 1996;Trefilov and Morozova, 2003).…”