澳大利亚深蓝色蓝宝石的热处理工艺

Heat Treatment of Dark Blue Sapphire from Australia

通过改变恒温温度、热处理气氛以及添加剂等热处理参数条件对澳大利亚深蓝色调蓝宝石进行热处理改色工艺研究,结果显示,在还原环境下600~800℃恒温12小时不利于改善蓝宝石的深蓝色调;在添加碳粉或开放环境下600~1300℃恒温12小时可以不同程度地改善蓝宝石的深蓝色调,当热处理温度高于1400℃时,蓝宝石深蓝色调增强,但碳粉创造的气氛环境难以掌控;在开放环境下添加Al(OH)3和TiO2粉末以1300℃恒温12小时后的改善效果最为明显,蓝宝石的深蓝色调明显减弱且颜色变得更加明亮。相关谱学测试表明,晶格中Fe^2+、Fe^3+、Ti^4+等致色微量元素离子的种类、含量及晶格位置的变化与澳大利亚蓝宝石的颜色改变相关,但紫外-可见光谱中吸收峰和吸收带的变化与热处理时气氛和温度的变化关系复杂。

In this paper,by changing the condition of heat treatment parameters,such as temperature,atmosphere and additives,the process of heat treatment of dark blue sapphire from Australia is studied.The heat treatment results show that the temperature of 600-800℃under reduced environment for 12 hours is not efficient for improving the dark blue tone of sapphire.The dark blue tone of the sapphire can be improved at the temperature of 600-1300℃for 12 hours under the environment with addition of carbon powder or open environment.When the temperature is higher than 1400℃,the dark blue tone of sapphire can be enhanced,but the atmosphere environment created by carbon powder is difficult to control.The improvement effect of adding Al(OH)3 and TiO2 powder at the temperature of 1300℃for 12 hours in open environment is the most obvious.Under that circumstances,sapphire’s dark blue tone has weakened and the colour has brightened.The variety,content and lattice position of Fe^2+,Fe^3+,Ti^4+and other colorized trace elements in the lattice are related to the colour change of Australian sapphire.However,the relationship between the change of absorption peak and band in UV-Vis spectrum is complicated.