of the scale with sulfur pressure.The preferred orientation of the grown scale changed with sulfur pressure and the orientation differences were quantitatively determined by means of X-ray pole figures.By using the diffusion theory as well as the present observations the effect of the preferred orientation of the scale on the overall corrosion rates was disclosed,The calculated value of 1/n as a measure of the pressure dependence of the corrosion rates is about 1/5.7. This value
dependence of interdiffusion coefficients (D) on the concentration of Al. From the values of coefficients the activation energies for interdiffusion (Q) were obtained as the function of Al concentration in the alloy. D at each temperature was strongly upon temperature in the Arrhenius plot showed a good linearity, from which the activation energy for interdiffusion was calculated. The energy decreased steeply with Al concentration down to 43kcal/mol in a disorder range and increased in an ordered range in general. But the activation energy showed a high value (69kcal/mol) at the initial stage of the ordered phase. Fine alumina markers placed initially on the test piece were found in the ordered phase after annealing at each temperature to shift to higher Al concentration with increasing temperature and the intrinsic diffusion coefficient of Al was about 1.4 to 2.0 times higher than that of Fe. The mean activation energies in the range of composition of 30.5 to 42.8 at% Al of both constituents were about the same (60kcal/mol).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.