Material for ceramic ball and method of manufacturing ceramic ball

Abstract

In material for ceramic ball that has a spherical portion of approximate sphere at both ends thereof and a belt-like portion at a center thereof over an entire circumferential direction, 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 preferable to be 1 mm or less. A width of the belt-like portion is preferable to be 5 mm or less. The material for ceramic ball can be used for material for bearing balls for instance. When applying in such a usage, the material for ceramic ball essentially consists of silicon nitride, Vickers hardness thereof being preferable to be 1400 or more. In the material for ceramic ball of the present invention, a difference between a diagonal diameter of a belt-like portion and a polar diameter of a spherical portion is set at 100 μm or less. As a result, the material is formed in a shape where the belt-like portion does not project from the spherical portion. Thereby, the belt-like portion of the material for ceramic ball and polar diameter of the spherical portion come into average contact with abrasives or the like. Accordingly, different from the case of the existing material, the belt-like portion can be suppressed from wearing and damaging the abrasives due to the contact.

Dependencies are inferred from the claim text.