Investigation of oxygen diffusion behavior in terbium using 18O2 isotopic tracking by high resolution SIMS

• The first time that the oxidation process of Tb can be displayed by NanoSIMS.
• 18O diffusion coefficient in Tb between 1.4×10−19 and 1.22×10−18 m2/s is proposed.
• We detected the localized defects nucleation and uniform growth stage.

High resolution secondary ion mass spectrometry (SIMS) analysis has been used to study the oxidation mechanisms when high purity terbium (Tb) metal is exposed to corroding environments containing 18O2 isotope. The diffusion coefficients for 18O in Tb at a natural atmosphere can be calculated, which plays an important role in subsequent purification and application in industry. Clear evidence has been shown for the characteristic distributions of 18O after the kinetic transitions. The migration behavior is correlated with the existence of defects in the metal which allow the corrosions occur as localized nucleation. A set of ionization model has been developed to describe the oxidation process.

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