3437.    ---------------.  [TRAVERS, A., AND DIEBOLD, R.]  [Isolation of Pure Cementite by Acid Attack of Ferrous Materials and Some of Its Physical Properties.]  Compt. rend., vol. 205, 1937, pp. 797-799; Chem. Abs., vol. 32, 1938, p. 895.

        Pure cementite, Fe3C, was isolated from a white cast Fe (C, 3.4%; Si, 0.3; Mn, trace) by anodic attack is an acid medium or by simple acid (AcOH) attack (abs. 89) and separated from C by treatment with C2HCl3 (d. 1.47), washing with EtOH and Et2O and drying in N2.  Thus obtained, it forms fine grains, greasy to the touch, Curie point 210.  The electrolytic potential relative to the calomel electrode (saturated KCl) is -0.3200 for pH 2.3, -0.500 for pH 7.3. The potential of the couple Fe3C-Fe is 0.230 at 18 in a neutral medium, but increases if the pH increases beyond 7.5.