Physicochemical Factors in the Dissolution of Thoria in Solid Nickel

Abstract

Measurements have been made of the thermodynamics and diffusivity of oxygen in dilute solution in nickel in the range 1050–1200° C. The dissolution of thoria in nickel was then studied by α-ray spectrometry in atmospheres of controlled oxygen partial pressure between 1295 and 1400° C. It was concluded that the rate-determining step in the dissolution process was the diffusion of thorium atoms in nickel, and that the presence of oxygen in solution in the metal enhanced this process.