| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing potassium niobate which enables the production of potassium niobate which hardly causes the crack generation. SOLUTION: In this method for producing potassium niobate, the original powder is charged into a cylindrical platinum crucible 20, the platinum crucible 20 is disposed in a heating furnace 10 having a temperature gradient, the original powder is melted at a high temperature to the melt state and, thereafter, at least either by moving the platinum crucible 20 or by cooling the inside of the furnace 10, the melt is solidified from one direction. In such a case, when the temperature gradient of the vertical direction in the platinum crucible 20 is made to be G deg.C/mm, the moving speed of the platinum crucible 20 is made to be V mm/hr and the cooling speed in the furnace 10 is made to be C deg.C/hr, the following relation is satisfied; C/G+V<=5.
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