| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a material for a ceramic ball capable of easy machining and suppressing wearing of an abrasive used for the machining. <P>SOLUTION: In the material for ceramic ball having a spherical portion of approximate sphere shape with a different ratio between a polar diameter and a polar diameter in the vertical direction at both ends thereof, having a belt-like portion over an entire circumferential direction formed at a center thereof, and being obtained by firing after press-molding, a difference between a diagonal diameter of the belt-like portion and a polar diameter of the spherical portion is 100 μm or less. A height of the belt-like portion from the spherical portion is 1 mm or less and a width of the belt-like portion is 5 mm or less, and the polar diameter of the spherical portion is 50 mm or less. <P>COPYRIGHT: (C)2011,JPO&INPIT |
