摘要
Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry （LA-ICP- MS）, electron spin resonance （ESR） and ultraviolet-visible （UV-vis） spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous （Fe^2＋） and ferric （Fe^3＋） is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3＋ ions before and after Be-treated heat treatments.
Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry （LA-ICP- MS）, electron spin resonance （ESR） and ultraviolet-visible （UV-vis） spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous （Fe^2＋） and ferric （Fe^3＋） is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3＋ ions before and after Be-treated heat treatments.
