Sintered silicon nitride member and ceramic ball
AssigneeNgk Spark Plug Co., Ltd.
InventorTomonori Niwa
Life of this patent
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Abstract
A sintered silicon nitride member formed predominantly of silicon nitride, wherein at least a surface of the sintered member has a lightness VS of 3.0 to 9.0 and/or a chroma CS of not greater than 3.0. The sintered member facilitates identification of defects such as pore and/or foreign matter of different color formed at the surface and is capable of enhancing inspection accuracy. Also disclosed is a sintered silicon nitride member in the form of a ceramic ball having such a lightness on its surface.
Claims16
A sintered silicon nitride member formed predominantly of silicon nitride, wherein at least a surface of the sintered member has a lightness VS of 3.0 to 9.0 and at least a surface-layer portion of the sintered member contains a cation of a transition metal element in an amount of 0.1% by weight to 3% by weight.
A sintered silicon nitride member formed predominantly of silicon nitride, wherein at least a surface of the sintered member has a lightness VS of 3.0 to 9.0, at least a surface-layer portion of the sintered member contains-a cation of a transition metal element in an amount of 0.1% by weight to 3% by weight, and a carbon-thickened layer having a carbon concentration higher than that of an inner-layer portion of the sintered member is formed in a surface-layer portion of the sintered member.
A sintered silicon nitride member formed predominantly of silicon nitride, wherein at least a surface of the sintered member has a lightness VS of 3.0 to 9.0, and said surface has a peak ratio of 0.05-0.5 represented by X2/X1, where X1 is an intensity of a peak appearing at 206±10 cm−1 and X2 is an intensity of a peak appearing at 1584±20 cm−1, respectively, obtained through Raman spectroscopy.
Dependencies are inferred from the claim text.