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The diffusion of oxygen in zirconium and dilute zirconium alloys has been studied in the temperature range of 400° to 5857deg;C by observing the rates of dissolution of anodically deposited interference oxide films. The diffusion coefficient of oxygen in zirconium depends on the grain orientation and varies by a factor of two among different orientations. Macroscopically observed average values obey the equation D,cm2/sec=9.4exp][ )(−51,780±220/RTwhere the activation energy for the diffusion of oxygen in zirconium is 51.78 kcal/mole. No macroscopic differences were observed in the diffusion coefficients of the various dilute alloys. Oxidation and corrosion rates have been observed to have an orientation dependence similar to that observed in the diffusion study. The mechanism of oxidation and corrosion is discussed in terms of diffusion of oxygen and adherence of oxide films.

Anodization of tantalum in electrolytes containing phosphorus or fluorine ions resulted in the incorporation of a quantity of these elements into the anodic film. While phosphorus was concentrated in the outer portions of such films, fluorine was attracted to the oxide/metal interface. We employed an ion microprobe mass spectrometer to examine the concentration profiles of these elements in films formed by a variety of anodization procedures. These experiments demonstrated the usefulness of the IMMS as a tool for such work and, in addition, furnished information on the characteristics of both film growth and the distribution and movement of these impurities. The influence of fluorine‐rich layers at the oxide/metal interface on the adherence of the anodic films was also shown.

Average of 5 results. 6 Based on 5-ppm standard; integration time of 40 sec; premeasurement time 40 sec.