LIGHT IMPURITIES IN OXIDIZING METAL FOILS

Distributions of implanted lithium ions and of natural boron impurities are monitored in titanium foils after isochronal annealing in high vacuum. A strong correlation between the shape of the depth profiles and the oxide growth in titanium is observed. In contrast, the depth distribution of lithium implanted into zirconium remains nearly unaltered up to high temperatures. The observed oxide growth of titanium in air at elevated temperatures is twice as fast as reported earlier. The activation energy for the oxide growth, 1.2 eV, could, however, be confirmed. Annealing in an oxygen-deficient atmosphere not only results in a retarded oxide growth rate but also exhibits a different activation energy (0.7 eV), which indicates different chemical oxidation reactions. © 1990.