| α-Al2O3 specimens were irradiated at room temperature (RT) and 1000°C to fluences of 1 × 10 17 B+/cm2, 3 × 1016 N+/cm2 and 1 × 1017 Fe +/cm2 with 150 keV of energy. Following irradiation, the structures were examined using the transmission electron microscopy (TEM), Rutherford backscattering-ion channeling (RBS-C) spectroscopy, optical absorption measurements, x-ray diffraction (XRD) technique, and x-ray photoelectron spectroscopy (XPS). The samples implanted at room temperature were then annealed for one hour at 1000°C in Ar-4%H2 and the microstructures examined.; The RT boron-implanted microstructure consists of the typical “black spot” radiation damage, which differs from the microstructural features observed at 1000°C. Cross-sectional TEM micrograph for the nitrogen-implanted at RT reveals a band of bubbles or voids; whereas the 1000°C N-implanted specimen exhibits “black spot” radiation damage generally ascribed to defect clusters. The microstructure of the iron-implanted sapphire at RT contains “black spot damage” clusters and small precipitates. The sample implanted with iron at 1000°C contains particles of iron as large as 50 nm and no evidence of “black spot” radiation damage. These iron particles were identified as α-Fe. The annealed microstructures were quite different from the as-implanted ones. None contained “black-spot damage” or interstitial defect clusters, but all contained evidence for small second phase particles. The annealing promoted the recombination of point defects and defect clusters and allowed the system to move toward the equilibrium phase compositions.; The lattice disorder as measured by RBS-C was greater far iron and boron implantation at RT than at 1000°C, but higher for nitrogen implanted at 1000°C. The optical absorption measurements indicate the presence of oxygen vacancies and defect clusters involving oxygen vacancies.; The depth-dependent microstructures of the irradiated specimens, the energy deposited (elastic and inelastic) as a function of depth from the surface, the range of implanted species, and the defect production were modeled using the transport and range of ions in materials (TRIM) program. The results of the model showed that the ionizing component of the irradiation did not noticeably affect the microstructures. |
