| 摘要 |
The present invention provides a rolling element capable of ensuring excellent corrosion resistance, and capable of maintaining a stable performance for a long time even in a case where a slight amount of a solution intrudes into the inside, with no occurrence of dry friction and the like between a rolling element and a raceway groove. For this purpose, the rolling element is comprised of an alumina sintered body with an alumina content of 99.5 mass % or more. The alumina sintered body has a bending strength by a three point bending test according to JIS-R 1601 of 320 MPa or more. The crystal particle constituting the alumina sintered body has an average grain size of less than 2 mum and a ratio of a standard deviation to the average grain size of 0.4 or less. The inner ring and the outer ring are comprised of the alumina sintered body, zirconia sintered body or synthetic resin.
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