3048.     ---------------.  [SCHENCK, R.]  [Chemical Equilibrium in the Reduction and Cementation of Iron.]  Ztschr. Elektrochem., vol. 24, 1918, pp. 248-255; Jour. Soc. Chem. Ind., 1918, A, p. 624; Chem. Abs., vol. 14, 1920, p. 396.

        In the interaction between Fe and CO, the Fe is carburized by C resulting from the decomposition of the CO.  This is concluded from a comparison of the temperature and pressure equilibrium involved in this reaction and those involved in the reaction C+CO₂=2 CO.  The unpublished work of Juschkewitsch on the equilibrium between 618°-718° in the reaction C+CO₂=2 CO in which metallic Co was used as a catalyzer furnishes the missing data for the temperature-pressure curve and makes possible the comparison.  The presence of the C resulting from the action Fe+CO is not shown by the usual treatment with HCl, since, having interacted with the ferrite, it is present as carbide.  The equilibrium between ferrite, carbide, and the oxides of Fe and C exist at low pressures.  The CO content of the gaseous phase is somewhat larger than that in the equilibrium C+CO₂=2 CO.  The carbide obtained in this manner is different from cementite Fe₃C in that it does not decompose into Fe+C on being heated to 400° and, according to theoretical consideration, contains less C.  This new carbide is likened to a manganese carbide, which is different from Mn₃C and contains enough C to correspond to Mn₇C or Mn₆C.  The new Fe carbide is named bunsenite after Robert Bunsen.