Spark plug and manufacturing method therefor
AssigneeNgk Spark Plug Co., Ltd.
InventorsTakaaki KIKAI, Daisuke SUMOYAMA, Takuto NAKADA
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Abstract
A spark plug comprising: a first electrode including a tip containing Ir as a main material, and a base member to which the tip is joined; and a second electrode opposed to the tip with a spark gap therebetween. The number of crystal grains appearing in a range of 0.25 mm2 on an arbitrary cross-section of the tip in a first direction connecting the tip and the second electrode within the spark gap, is not less than 20. When a length of each of the crystal grains in the first direction is denoted by Y, and a length of each of the crystal grains in a second direction perpendicular to the first direction is denoted by X, 5 μm≤X≤100 μm and Y/X≥1.5 are satisfied.
Claims13
A spark plug comprising:
- a first electrode including a tip containing Ir as a main material, and a base member to which the tip is joined;
- and
- a second electrode opposed to the tip with a spark gap therebetween, wherein
- a number of crystal grains appearing in an area of 0.25 mm2 on an arbitrary cross-section of the tip in a first direction connecting the tip and the second electrode within the spark gap, is not less than 20 crystal grains, and
- when a length of each of the crystal grains in the first direction is denoted by Y and a length of each of the crystal grains in a second direction perpendicular to the first direction is denoted by X, 5 μm≤X≤100 μm and Y/X≥1.5 are satisfied.
Dependencies are inferred from the claim text.