PRODUCTION OF SINTERED COMPACT OF YTTRIUM OXIDE

摘要

PROBLEM TO BE SOLVED: To reduce dispersion in rectilinear transmissivity by controlling atmosphere in a reaction tank so that a definite equilibrium state is kept between carbon dioxide partial pressure in atmosphere in the reaction tank and carbon dioxide partial pressure in reaction solution while keeping a reaction solution constant within a specific temperature range and carrying out aging of yttrium carbonate. SOLUTION: The temperature of reaction solution of yttrium carbonate during aging is controlled within the range of 25-40 deg.C. Preferable temperature is 30 deg.C and the temperature is controlled within the range of±3.0 deg.C. Although a method for controlling atmosphere in a reaction tank can be carried out by providing a vent hole having a prescribed size in the upper lid of the reaction tank, forced ventilation is not usually required therefor. It is preferable so as to uniformly produce nucleus of yttrium carbonate in a definite value or above in the reaction tank. A rate enough to uniformly produce nucleus of yttrium carbonate in a definite value or above in the reaction tank and control crystal growth of yttrium carbonate is preferably selected as a stirring rate of yttrium carbonate during aging.