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The diffusivity of tritium in rutile single crystals has been measured parallel to the a and c axes in the temperature range 250–900 °C. Raman-scattering measurements were also made to aid in identifying a nonpolar tritium species involved in the diffusion process. Two species, OT− ions and T2 molecules, are involved in tritium migration. The OT− ions dissociate preceding each tritium jump. Along the a axis the T2 molecules diffuse four orders of magnitude slower than the T+ ions associated with OT−. No dependency of the tritium diffusivity upon the rutile defect structure was observed.

A study was made of the structural details of thin oxide films formed on the (100), (111), (110), and (311) of nickel. Oxidation temperatures ranged from 400° to 600°C, and the oxide films produced were between 25 and 500Aå thick. An x‐ray technique was utilized to measure the average strain in the films, the mosaic spread, the thickness, and the epitaxial relationships between oxide and metal. The oxide films on all crystal planes studied were observed to contain large numbers of short circuit diffusion paths. A change in the extent of these diffusion paths in the oxide on a given crystal plane produced a corresponding change in the oxidation rate. Furthermore, there was a variation in the extent and efficiency of the short circuit diffusion paths as a function of crystallographic orientation of the substrate, and this variation correlated directly with the marked oxidation rate anisotropy exhibited by nickel.

The kinetics of oxidation of Zircaloy-4 in steam were examined under isothermal conditions from 900 ~ to 1500~C. Rate curves describing the growth of the reaction product layers, oxide-and oxygen-stabilized alpha, were obtained at 50~ intervals under carefully defined and documented experimental, conditions. The early stages of oxidation for temperatures above 1000~ were shown to be virtually ideally parabolic; below 1000~ the growth of the oxide layer was nonparabolic. Statistical evaluations of the data in terms of the rate constants and their Arrhenius parameters established the high degree of self-consistency of these measurements. The features of the experimental apparatus and techniques that were necessary to insure accurate measurements are discussed.