CONCENTRATION DEPENDENCE OF DIFFUSION OF COBALT IN NICKEL-COBALT ALLOYS

In the present paper the results of measuring the self-diffusion coefficients for Co in Ni-Co alloy in the composition interval 20-100 at. % Co, and in the temperature range 1057-1306°C are given. The measurements were carried out by the Gruzin method using the radioisotope Co-60. On the curves indicating the concentration dependence of the diffusion coefficient arid of the diffusion characteristics log D0 and ΔAH, extrema appear in the neighbourhood of the compositions 70at.% Co and 25at.% Co. The existence of these extrema is discussed from the point of view of the equilibrium diagram Ni-Co, the extremum near 25at.% Co is explained by means of the Cohen-Fine model for short range order. © 1969.