山东蓝宝石(刚玉)热处理改善研究

Heat Treating Enhancement of Sapphires from Shandong

本文采用高温热处理法，对山东蓝宝石进行改善实验，其内容主要涉及消除色斑，消除丝状包裹体，减轻蓝宝石发黑（色太深）现象。在此基础上对蓝宝石高温热处理改善机理进行探讨，研究认为：（１）高温环境下通过缺陷传递使晶格中Ｆｅ２＋变为Ｆｅ３＋；（２）恒温时间的变化率为粒径变化率的两倍；（３）降温速率极限为：φ＝ＲＳｆ（Ｔ）ｒ２；（４）改善后蓝宝石总带灰色色调的主要原因是Ｆｅ２＋－Ｆｅ３＋荷移加强和纳米级包裹体数量增加所致。

In this paper, heat treatment experiments on sapphires from Shandong province, China, have been undertaken.It mainly includes removing taxtic colors or needle inclusions, and lightening deep blue hues. On these bases, study on heat treatment theory has been going on. In the end, it reach the following results: A. With chain transfer of point defect in the sapphire crystal, divalent irons can be changed into trivalent irons in the oxidixing atmosphere; B. The relationship between lasting time at maximum temperature( t )and radius ( r ) of sapphire is:d t t =2d r r ;C. Rate of decreasing temperature is less than φ= RSf(T) r 2; and D. Besides intensification of transfer transition between di_ and trivalence irons, increasing of population of liquid or gas inclusions in nanometer scale are account for gray hues in treated sapphires.