3663. ---------------. [WERT, C. A.] Diffusion Coefficient of Carbon in Alpha-Iron. Phys. Rev., vol. 79, 1950, pp. 601-605; Chem. Abs., vol. 44, 1950, p. 9760.
Equation of the form D=Doe-∆H/RT is developed for interstitial diffusion in cubic lattices. This development uses a classical statistical mechanical treatment. Measurements of D for C in a-Fe were made, -35° to 200°. Combined with earlier data they extend the knowledge of D in this system from D=10-20 to D=10-6 cm.2 per sec. The values of Do and ∆H obtained by fitting this equation to the experimental points give Do=0.02 cm.2 per sec. and ∆H=20,100 cal. per mol.