| 摘要 |
PURPOSE:To obtain a core tube for a metal vapor laser having a long life and excellent characteristics, by using a specified alumina ceramics polycrystalline material. CONSTITUTION:An alumina ceramics polycrystalline material is used, wherein the total amount of impurity except magnesia or magnesium compounds is smaller than or equal to 1000 ppm, and the density is more than or equal to 3.95 g/cm<3>. Magnesia is an effective additive as a crystal growth inhibitor for alumina ceramics. As to the correlation between the total amount of impurity except magnesia and characteristics of a metal vapor laser tube, the smaller amount of impurity the preferable, and the value less than or equal to 1000 ppm is satisfactory. When the density is more than or equal to 3.95 g/cm<3>, the plastic deformation speed is small at a temperature higher than or equal to 1500 deg.C, operating temperature of the metal vapor laser tube. Therefore, a laser alumina core tube having excellent characteristics and a long life can be obtained. |
