Diffusion du fer radioactif dans le volume et les joints de grains du cobalt, massif ou poreux

Abstract

The diffusion coefficient of radioactive Fe 59 in volume and in grain boundaries of both porous and solid cobalt were compared. It leads to following conclusions: —The volume diffusion coefficients of iron in cobalt corresponds to the equation D = 0.2 exp (−55500/ RT) cm 2/sec for the whole range of temperature of 930 to 1240°C. —The presence of pores in the sintered metal promotes volume- and intergranular diffusion. A rapid review of the method enabling the simultaneous measure of volume- and intergranular diffusions by radiation counting on a same sample is included in this paper. By using autoradiograph, it was possible to show some phenomena of the structure, particularly the structural “heredity” occurring in the transformation of β cubic face centred to a hexagonal cobalt.