Title:
PREPARATION OF LITHIUM TETRABORATE SINGLE CRYSTAL
Document Type and Number:
Japanese Patent JPS5820797
Kind Code:
A
Abstract:
PURPOSE:To obtain lithium tetraborate single crystal without containing air bubbles, by pulling up a seed crystal from a melt of the lithium tetraborate which is a raw material filled in a crucible in an oxidizing atmosphere at a specified upper limit crucible temperature. CONSTITUTION:A commercially available lithium tetraborate of high purity is filled in a Pt crucible 1, which is heated by the high-frequency heating. The temperature of the brim of the crucible 1 is measured by a thermocouple 13, and the temperature is kept at 960 deg.C to melt the raw material and stabilize the melt 2. The temperature is then reduced to 950 deg.C thereafter, and a seed crystal in the a-axis orientation is brought into contact with and seeded in the melt 2. A lithium tetraborate single crystal is then pulled up and grown at a given pulling up rate and a number of revolutions. As a result, the colorless and transparent crystal without containing air bubbles is grown in high yield, and corrosion is scarcely found in the Pt crucible 1. In case the crucible temperature is kept at 960 deg.C or above, e.g. 1,020 deg.C, and the crystal is grown at 970 deg.C, air bubbles are contained in the pulled up crystal, and the Pt crucible shows a reduction in weight of 3% in one crystal growing step.
Inventors:
MATSUMURA SADAO
USHIZAWA JISABUROU
FUKUDA TSUGUO
USHIZAWA JISABUROU
FUKUDA TSUGUO
Application Number:
JP11527781A
Publication Date:
February 07, 1983
Filing Date:
July 24, 1981
Export Citation:
Assignee:
TOKYO SHIBAURA ELECTRIC CO
International Classes:
C01B35/00; C30B15/00; C30B29/10; (IPC1-7): C01B35/00; C30B15/00; C30B29/22
Attorney, Agent or Firm:
Noriyuki Noriyuki