Abstract: Provided is an Ir alloy which is excellent in high temperature strength while ensuring oxidation wear resistance at high temperature. The Ir alloy consists of: 7 mass % or more, and less than 10 mass % of Rh; 0.5 mass % to 5 mass % of Ta; 0 mass % to 5 mass % of at least one kind of element selected from among Co, Cr, and Ni; and Ir as the balance, wherein a total content of the Ta and the at least one kind of element selected from among Co, Cr, and Ni is 5 mass % or less.

Abstract: Provided is an Ir alloy, which is further improved in Vickers hardness. Specifically, provided is a heat-resistant Ir alloy, including: 5 mass % to 30 mass % of Rh; 0.5 mass % to 5 mass % of Ta; and 0.003 mass % to 0.15 mass % of at least one kind selected from the group consisting of: Sc; Hf; and W, with the balance being Ir.

Abstract: Provided is an Ir alloy wire, which is further improved in oxidation wear resistance while ensuring a Vickers hardness. The Ir alloy wire includes: 5 mass % to 30 mass % of Rh; and 0.5 mass % to 5 mass % of Ta, wherein an average value A for an aspect ratio (crystal grain length/crystal grain width) of a structure of the alloy wire in a range of a depth of 0.05 mm or less from a surface of the alloy wire satisfies 1?A<6.

Abstract: Provided is an Ir alloy which is excellent in high temperature strength while ensuring oxidation wear resistance at high temperature. The Ir alloy consists of: 7 mass % or more, and less than 10 mass % of Rh; 0.5 mass % to 5 mass % of Ta; 0 mass % to 5 mass % of at least one kind of element selected from among Co, Cr, and Ni; and Ir as the balance, wherein a total content of the Ta and the at least one kind of element selected from among Co, Cr, and Ni is 5 mass % or less.

Abstract: Provided is an Ir alloy, which is further improved in Vickers hardness. Specifically, provided is a heat-resistant Ir alloy, including: 5 mass% to 30 mass% of Rh; 0.5 mass% to 5 mass% of Ta; and 0.003 mass% to 0.15 mass% of at least one kind selected from the group consisting of: Sc; Hf; and W, with the balance being Ir.

Abstract: Provided is an Ir alloy wire, which is further improved in oxidation wear resistance while ensuring a Vickers hardness. The Ir alloy wire includes: 5 mass % to 30 mass % of Rh; and 0.5 mass % to 5 mass % of Ta, wherein an average value A for an aspect ratio (crystal grain length/crystal grain width) of a structure of the alloy wire in a range of a depth of 0.05 mm or less from a surface of the alloy wire satisfies 1?A<6.

Abstract: An Ir alloy is excellent in high temperature strength while ensuring oxidation wear resistance at high temperature. The heat-resistant Ir alloy includes: 5 mass % to 30 mass % of Rh; 0.3 mass % to 5 mass % of an element group A made of at least one kind of element selected from among Ta and Re; and 0 mass % to 5 mass % of an element group B made of at least one kind of element selected from among Co, Cr, and Ni, wherein the heat-resistant Ir alloy includes 5 mass % or less of the element group A and the element group B in total, and wherein, when the at least one kind of element in the element group A includes Re, the at least one kind of element in the element group B is Co alone, Cr alone, or two or more kinds selected from Co, Cr, and Ni.

Abstract: A spark plug electrode is provided, in which an electrode member in which a total of 0.3 to 7.5 wt % of at least one of Ta and Nb is added to an IrRh alloy is provided at a discharge part.

Abstract: A spark plug electrode is provided, in which an electrode member in which a total of 0.3 to 7.5 wt % of at least one of Ta and Nb is added to an IrRh alloy is provided at a discharge part.

Abstract: A center electrode is held in insulating glass, in which a tip end portion of the center electrode protrudes. A ground electrode has a connection part connected to a housing. The ground electrode forms a spark discharge gap between the center electrode and the ground electrode. The ground electrode has a ground base material that includes the connection part and a ground protrusion part that protrudes from the ground base material toward the center electrode and forms the spark discharge gap between the center electrode and the ground electrode. An angle between a ground discharge surface of the ground protrusion part and a side surface of the ground protrusion part is a right angle or an acute angle. At least a portion of the side surface of the ground protrusion part and at least a portion of a side surface of the ground base material are flush with each other.

Abstract: A center electrode is held in insulating glass, in which a tip end portion of the center electrode protrudes. A ground electrode has a connection part connected to a housing. The ground electrode forms a spark discharge gap between the center electrode and the ground electrode. The ground electrode has a ground base material that includes the connection part and a ground protrusion part that protrudes from the ground base material toward the center electrode and forms the spark discharge gap between the center electrode and the ground electrode. An angle between a ground discharge surface of the ground protrusion part and a side surface of the ground protrusion part is a right angle or an acute angle. At least a portion of the side surface of the ground protrusion part and at least a portion of a side surface of the ground base material are flush with each other.

Abstract: An Ir alloy is excellent in high temperature strength while ensuring oxidation wear resistance at high temperature. The heat-resistant Ir alloy includes: 5 mass % to 30 mass % of Rh; 0.3 mass % to 5 mass % of an element group A made of at least one kind of element selected from among Ta and Re; and 0 mass % to 5 mass % of an element group B made of at least one kind of element selected from among Co, Cr, and Ni, wherein the heat-resistant Ir alloy includes 5 mass % or less of the element group A and the element group B in total, and wherein, when the at least one kind of element in the element group A includes Re, the at least one kind of element in the element group B is Co alone, Cr alone, or two or more kinds selected from Co, Cr, and Ni.

Abstract: Disclosed herein is a spark plug capable of suppressing electrode consumption caused by a spark discharge and a method of manufacturing the same. A section except a welded section formed by welding a tip surface of a center electrode is defined as an unwelded section in side surfaces of a center chip, and a length of the unwelded section along a center axis of the center chip is defined as an unwelded section length. Under this definition, the welded section is formed in order for an unwelded section length in a side surface opposite to an inclination direction side of the center chip in the center chip to become longer than an unwelded section length in a side surface of the inclination direction side of the center chip in the center chip.

Abstract: In the spark plug, at least one of the center chip and the ground chip is bonded with a center electrode or a ground electrode. The selected chip has a first part formed so as to linearly extend along a first center axis of an electrode bonded with the first part and a second part formed so as to extend linearly from a tip end of the first part along a second central axis inclined with respect to the first central axis.

Abstract: A spark plug has an elongated center electrode, ground electrode, convex part and noble metal coating layer. The center electrode is held in a housing. The ground electrode has a tip end opposing part opposing the center electrode. The convex part is extended from the tip end opposing part to an opposing part face in an axial direction of the spark plug. A spark discharge gap is formed between a tip end part of the center electrode and the convex part. The noble metal coating layer covers a surface of the convex part. The noble metal coating layer has an end face coating layer covering a projecting end face of the convex part and a side face coating layer covering at least a part of a side face of the convex part extended from the projecting end face. A root part of the side face coating layer is buried in the tip end opposing part. An extension is formed so that at least a part of the root part is extended to an outside of the spark plug along the opposing part face.

Abstract: In the spark plug, at least one of the center chip and the ground chip is bonded with a center electrode or a ground electrode. The selected chip has a first part formed so as to linearly extend along a first center axis of an electrode bonded with the first part and a second part formed so as to extend linearly from a tip end of the first part along a second central axis inclined with respect to the first central axis.

Abstract: A spark plug has an elongated center electrode, ground electrode, convex part and noble metal coating layer. The center electrode is held in a housing. The ground electrode has a tip end opposing part opposing the center electrode. The convex part is extended from the tip end opposing part to an opposing part face in an axial direction of the spark plug. A spark discharge gap is formed between a tip end part of the center electrode and the convex part. The noble metal coating layer covers a surface of the convex part. The noble metal coating layer has an end face coating layer covering a projecting end face of the convex part and a side face coating layer covering at least a part of a side face of the convex part extended from the projecting end face. A root part of the side face coating layer is buried in the tip end opposing part. An extension is formed so that at least a part of the root part is extended to an outside of the spark plug along the opposing part face.

Abstract: A spark plug is provided, which includes a housing, an insulation porcelain, a center electrode, a main ground electrode, a first sub ground electrode and a second sub ground electrode. The first and second sub ground electrode are arranged being opposed to each other. Requirements of Hs1<Hc+Gm, Gm<Gs1+Gg, Gm<Gs2+Gg, Hs2?Hs1 and Hc<Hs2 are satisfied, where Hc is the length of projection of the center electrode, Gm is the size of the main gap, Hs1 is the length of projection of the first sub ground electrode, Hs2 is the length of projection of the second sub ground electrode, Gs1 is the length of the first sub gap in the radial direction of the plug, Gs2 is the length of the second sub gap in the radial direction of the plug, and Gg is the distance between an outer peripheral edge portion and an inner peripheral edge portion of a porcelain tip portion in the radial direction of the plug.

Abstract: A spark plug for an internal combustion engine includes a housing, an insulation porcelain, a center electrode and a ground electrode. Both of a tip portion of the center electrode and an opposing portion of the ground electrode are provided with respective projection portions which are projected toward a spark discharge gap. At least one of the projection portions has an opposing face that confronts the spark discharge gap and is inclined with respect to a plane perpendicular to an axial direction of the plug. The spark discharge gap is configured to be gradually enlarged, in one direction perpendicular to the axial direction of the plug, from a narrow gap on one end side toward a wide gap on the other end side.

Abstract: A spark plug for an internal combustion engine is provided, which includes a housing, an insulation porcelain, a center electrode and a ground electrode. At least one of a tip portion of the center electrode and an opposing portion of the ground electrode is provided with a projection portion. At least one of the projection portions has a cross section perpendicular to the axial direction of the plug, the cross section having a minimum curvature radius portion and being in a specific shape that satisfies a predetermined requirement. The requirement is that, when a first straight line, a first line segment and a second straight line are provided, and when the cross section is divided into a first region and a second region by the second straight line, the second region has an area larger than the area of the first region.