Title:
PRODUCTION OF LITHIUM TETRABORATE SINGLE CRYSTAL
Document Type and Number:
Japanese Patent JPS63215599
Kind Code:
A
Abstract:
PURPOSE:To prevent occurrence of crack and improve workability, by regulating increasing rate of crystal size in head part-growing process to specific range when lithium tetraborate single crystal consisting of head part and cylindrical part is produced by a pulling-up method. CONSTITUTION:A melt 5 of raw material consisting of lithium tetraborate is housed in a crucible 1 and the surface of the raw material melt 5 is brought into contact with a seed crystal 8 and the melt is pulled up while rotating the seed crystal 8 and the crystal is gradually grown to provide the lithium tetraborate single crystal 6 consisting of head part A and cylindrical part B. Increasing rate of the crystal size is regulated within the range of 10-40mm/hr by controlling cooling rate of the melt 5 after contact with the seed crystal 8 in a growing process of the head part A having diameter corresponding to 20-95% of diameter of the cylindrical part B when the single crystal 6 is produced. Thus the lithium tetraborate single crystal reduced in occurrence of crack is obtained and time for forming the head part A can be shorten at the same time.
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Inventors:
USHIZAWA JISABURO
TAKEMURA HIROBUMI
TAKEMURA HIROBUMI
Application Number:
JP4873487A
Publication Date:
September 08, 1988
Filing Date:
March 05, 1987
Export Citation:
Assignee:
TOSHIBA CORP
International Classes:
C30B15/20; C30B29/10; C30B29/22; (IPC1-7): C30B15/20; C30B29/22
Attorney, Agent or Firm:
Noriyuki Noriyuki