| 초록 |
Metal impurities atoms such as iron and titanium often replace aluminum atoms in the crystal lattice of sapphire. The color formation in sapphire is well known to occur as a result of inter-valence charge transfer (IVCT) in the sapphire crystals. Iron impurities are generally either in Fe2+ or Fe3+ state in the sapphire crystal. The presence of titanium in sapphire does not produce color by itself. If both iron and titanium are present together in the crystal, sapphire tends to have a deep blue color. In the study, we investigated the color changes and spectral characteristic of sapphire which were classified tin to dark blue, yellow, green following heat treatment. The treatment was performed at 800~1600℃. The sapphire samples were investigated before and after heat treatment by UV-Vis, FT-IR, and WD-XRF spectroscopy. Based on the results, the causes of the color changes of the various colors of sapphire samples as a result of heat treatment were investigated. |
