3757.     YOSHISAKI, H.  [Velocity of Decomposition of Cementite.]  Sci. Repts. Tôhoku Imp. Univ., Ser. A, vol. 1, No. 1, 1949, p. 63-70; Chem. Abs., vol. 44, 1950, p. 9887.

        In the conversion of white cast Fe to gray, namely, decomposition of cementite to Fe and graphite, it is assumed that:  (1) The reaction occurs selectively at the surfaces of a number of singular points, as reaction nuclei; (2) the number of reaction nuclei diminishes as the reaction continues; and (3) the velocity of movement of a reaction zone in a fixed direction in a homogeneous crystal grain of the reactant does not vary at constant temperature.  On the basis of these assumptions, the following empirical equation was derived for the reaction velocity constant as a function of temperature, C, and Si contents:  K=5.8 x 10²⁰ C^4.0 Si^4.3_ T^1/2 e^_40000/T.

        YOUNG, D. W.  See abs. 3238.

        YUGUCHI, M.  See abs. 1119, 1120.

        YUKIO, U.  See abs. 2019.

        ZABOLOTSKIĬ, T. V.  See abs. 2913.