温梯法蓝宝石（Al2O3）晶体的脱碳去色退火研究

The sapphire boulegrown by TGT is a bit colorful due to the volatilization of graphite heater at high temperature and absorptions of transitional metal ions in raw material. It is light red at the shoulder and little yellow at the bottle of the sapphire boule, respectively. The as grown sapphire boule (phi 110x80mm(3)) turns out colorless and transparent after being decolourized and decarbonized in air and hydrogen successively at high temperature. The quality, optical transmissivity and homogeneity of the sapphire boule have remarkably improved.