2923.     ---------------.  [RUFF, O.]  [Phase-Rule Diagrams of Carbon With Nickel, Iron, Cobalt, and Manganese.]  Ber. deut. chem. Gesell., vol. 45, 1912, pp. 3139-3148; Chem. Abs., vol. 7, 1913, p. 581.

        In his electric vacuum furnace, Ruff has succeeded in maintaining temperatures up to above 2,700°.  Thus the melting-point diagram of the V-C system has been followed to about 2,750°.  In the Fe-C system, the probable existence of Fe₃C has been revealed, and in the Ni-C system, the compound Ni₃C was found.  The melting point and vapor pressure diagrams of these systems are reproduced, together with those of Mn-C and Co-C, worked out with the help of Gersten and Keilig.  In the Mn-C system the compound Mn₃C appears to be more stable than any of the above mentioned compounds.  Unlike the other carbides, Mn₃C forms a continuous series of mixed crystals with Mn.  In the Co-C series, the formation of fumes at high temperatures caused so much trouble that the work is to be repeated.  The melting point-diagram is very similar to that of Ni-C, although no transition point could be detected in the liquid before the boiling point was reached.  (See also abs. 2924 and 2933.)

                    RUFF, O., AND BORMANN, W.  [Investigations at Higher Temperatures.  VII.  Iron and Carbon.]  See abs. 2931.

        ----------.  [Investigations at Higher Temperatures.  V.  Manganese and Carbon.]  See abs. 2929.

        ----------.  [Investigations at Higher-Temperatures.  VI.  Nickel and Carbon.]  See abs. 2930.