Chinese Optics Letters, 2016, 14 (5): 053001, Published Online: Aug. 6, 2018
Study on low-temperature heat treatment of purplish red sapphire Download: 899次
Abstract
A light purplish red sapphire is heat treated in an airtight crucible. The sample changes little in color after receiving heat treatment at 1100°C, but turns to light blue and blue after being treated at 1200°C and 1300°C, respectively. Before heating, the UV-VIS absorption spectra of the sample are dominated by the 551 nm broad absorption band contributed by the d -electron transition A 2 4 → T 2 4 of Cr 3 + . After heating, the UV-VIS absorption spectra are dominated by the 563 nm broad absorption band contributed by the intervalence charge transfer of Fe 2 + Ti 4 + . The x ray photoelectron spectroscopy test reveals that the Fe 2 + and Ti 4 + ion contents increase with increasing temperature. The sapphire changing from light purplish red to blue in the heating process is owing to the fact that the Fe 2 + and Ti 4 + contents grow and the intervalence charge transfer of Fe 2 + Ti 4 + selectively absorbs UV-VIS light.
Xiaozhen Han, Yan Kang, Xiao Wu, Xueliang Liu, Shouguo Guo. Study on low-temperature heat treatment of purplish red sapphire[J]. Chinese Optics Letters, 2016, 14(5): 053001.