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.