285.    BOERICKE, F. S.  Equilibria in the Reduction of Chromium Oxide by Carbon, and Their Relation to the Decarburization of Chromium and Ferrochrome.  Bureau of Mines Rept. of Investigations 3747, 1944, 34 pp.; Chem. Abs., vol. 38, 1944, p. 3539.

                 Reduction of Cr₂O₃ by C involves 4 distinct reversible-reaction steps:  (1) 3Cr₂O₃+13C=2Cr₃C₂+9CO; (2) 5Cr₂O₃+27Cr₃C₂=13Cr₇C₃+15CO; (3) 5Cr₂O₃+14Cr₇C₃=27Cr₄C+15CO; (4) Cr₂O₃+3Cr₄C=14Cr+3CO.  Describes apparatus and methods for measuring equilibria in these reaction steps, and thermodynamic values for each reaction are derived from equilibrium and requisite auxiliary-thermal data.  The resulting thermal properties of the Cr carbides show that each carbide is stable with respect to dissociation into the other 2 carbides.  A theoretical consideration is given of the decarburization of Cr and ferrochrome by Cr₂O₃, Fe₃O₄, H₂, and Si.  Cr₂O₃ is an effective decarburizing agent at 2,000°, particularly if means are furnished for operating under low CO partial pressures.  Magnetite, theoretically, is a more effective decarburizer than Cr₂O₃, but in practice the rapid exchange of Fe in the refining agent with Cr in the metallic phase results in about the same net effectiveness as for Cr₂O₃.  Both H₂ and Si are unsatisfactory agents for decarburizing Cr or ferrochrome.

         -------------- See abs. 1729.

                 BOGOYAVLENSKAYA, A. N.  See abs. 1806.

                 BOGROW, A.  See abs. 2174.

                 BOGUSLAVSKI, I. M.  See abs. 1671.

                 BÖHM, H.  See abs. 1711, 1713, 1717.

                 BÖKMANN, J.  See abs. 3052, 3053.

                 BOLLHORN, A.  See abs. 1504.

                 BOLTUS-GORUNEANU, M.  See abs. 659.