Copper, iron and zirconium implantation into polycrystalline α-Al2O3

Abstract Polycrystalline α -Al 2 O 3 samples have been implanted by 10 17 Zr, Fe or Cu ions/cm 2 at 110 keV in order to form oxide precipitates in the near-surface region after annealing in air. A chemical and microstructural characterization has been performed on the as-implanted surface and on the samples annealed in the temperature range from 600 to 1600°C. The nature of the chemical phases and the precipitate evolution have been characterized by combining RBS, XPS, GXRD, CEMS, TEM and SEM techniques. XPX, CEMS and TEM experiments on as-implanted specimens detect copper, iron and zirconium as Cu° (small metallic precipitates), Fe° (small α-iron precipitates), Fe II (associated with FeAl 2 O 4 ), and Fe IV (metastable state), Zr° and Zr IV (ZrO 2 ) in the as-implanted region. Analyses carried out after heat treatments between 600 and 1000 °C indicate a complete surface oxidation in this temperature range. Additionally, some precipitates appear along grain boundaries. Annealing at temperatures ranging from 1000 to 1600°C leads to drastic surface composition changes. The stability and size of the different observed precipitates (ZrO 2 , AlFeO 3 , Fe 2 O 3 , Fe 3 O 4 , CuO, CuAl 2 O 4 ) strongly depend on the annealing temperature.