Abstract: A spark plug comprising a center electrode, a ground electrode disposed on the center electrode across a gap, and a tip joined to an opposed surface of the ground electrode that is opposed to the center electrode, the tip has a discharge layer and a relieving layer, the relieving layer is formed from a Pt—Ni alloy and joined to the opposed surface via a diffusion layer, the discharge layer is formed from a Pt—Rh alloy and joined via a clad diffusion layer to a side of the relieving layer opposite to a side of the relieving layer at which the ground electrode is joined, and 0.81?A/B?1.21 is satisfied when an average cross-sectional area of the discharge layer is A mm2 and an average cross-sectional area of the relieving layer is B mm2, and a method for producing the spark plug.

Abstract: An electrode tip for a spark plug, wherein Pt is contained as a main component, 7% by mass or more of Rh is contained, and a total content of Pt and Rh is greater than or equal to 95% by mass. The electrode tip includes: a narrow portion having the same cross-sectional shape in a direction of an axis; and a wide portion which is adjacent to the narrow portion and has a cross-sectional area, in a radial direction, which is greater than the narrow portion.

Abstract: An object of the present invention is to provide a spark plug which includes, at at least one of a center electrode and a ground electrode, a tip having excellent spark wear resistance in a high temperature environment, thereby having excellent durability. A spark plug includes a center electrode and a ground electrode disposed with a gap provided between the center electrode and the ground electrode. At least one of the center electrode and the ground electrode includes a tip which defines the gap. The tip includes a metal base material containing Ir as a main component, and oxide particles containing at least one of oxides having a perovskite structure represented by general formula ABO3 (A is at least one element selected from elements in group 2 in a periodic table, and B is at least one element selected from metal elements). When a cross section of the tip is observed, an area proportion of the oxide particles is not lower than 1% and not higher than 13%.

Abstract: A spark plug comprising a center electrode, a ground electrode disposed on the center electrode across a gap, and a tip joined to an opposed surface of the ground electrode that is opposed to the center electrode, the tip has a discharge layer and a relieving layer, the relieving layer is formed from a Pt—Ni alloy and joined to the opposed surface via a diffusion layer, the discharge layer is formed from a Pt—Rh alloy and joined via a clad diffusion layer to a side of the relieving layer opposite to a side of the relieving layer at which the ground electrode is joined, and 0.81?A/B?1.21 is satisfied when an average cross-sectional area of the discharge layer is A mm2 and an average cross-sectional area of the relieving layer is B mm2, and a method for producing the spark plug.

Abstract: An object of the present invention is to provide a spark plug which includes, at at least one of a center electrode and a ground electrode, a tip having excellent spark wear resistance in a high temperature environment, thereby having excellent durability. A spark plug includes a center electrode and a ground electrode disposed with a gap provided between the center electrode and the ground electrode. At least one of the center electrode and the ground electrode includes a tip which defines the gap. The tip includes a metal base material containing Ir as a main component, and oxide particles containing at least one of oxides having a perovskite structure represented by general formula ABO3 (A is at least one element selected from elements in group 2 in a periodic table, and B is at least one element selected from metal elements). When a cross section of the tip is observed, an area proportion of the oxide particles is not lower than 1% and not higher than 13%.

Abstract: A spark plug wherein least one of a center electrode and ground electrode includes a shaft portion and an electrode tip joined to one surface of the shaft portion. The shaft portion includes a first core formed of a material containing copper and a first outer layer that is formed of a material having higher corrosion resistance than the first core and covers at least part of the first core. The electrode tip includes a second outer layer that is formed of a material containing a noble metal and forms the outer surface of the electrode tip and a second core that is formed of a material having a higher thermal conductivity than the second outer layer and is at least partially covered with the second outer layer.

Abstract: A spark plug having a tip provided on at least one of a center electrode and a ground electrode. The spark plug includes a center electrode and a ground electrode disposed providing a gap with the center electrode. At least one of the center electrode and the ground electrode includes a tip forming the gap. The tip has a main constituent of Ir. The tip contains Rh of 7 mass % or more to 31 mass % or less, Ru of 5 mass % or more to 20 mass % or less, and Pt of one-twentieth or more to one-half or less of a Ru content.

Abstract: A spark plug that includes a center electrode and a ground electrode. The center electrode is disposed providing a gap with the center electrode. At least one of the center electrode and the ground electrode includes a tip forming the gap. The tip includes a main body portion and a front surface layer. A composition of the main body portion is Pt as a main constituent and Rh of 5 mass % or more and Ni of 0 mass % or more to less than 8 mass %. The front surface layer is disposed at least at a surface radially outside of an axial line extending in a direction from a center of the main body portion to the gap. The front surface layer contains Ni of 8 mass % or more and has a thickness of 2 ?m or more.

Abstract: A spark plug having a tip provided on at least one of a center electrode and a ground electrode. The spark plug includes a center electrode and a ground electrode disposed providing a gap with the center electrode. At least one of the center electrode and the ground electrode includes a tip forming the gap. The tip has a main constituent of Ir. The tip contains Rh of 7 mass % or more to 31 mass % or less, Ru of 5 mass % or more to 20 mass % or less, and Pt of one-twentieth or more to one-half or less of a Ru content.

Abstract: In a spark plug, at least either of a center electrode and a ground electrode has a tip which defines a gap, a tip provided on at least either of a center electrode and a ground electrode contains Ir, Rh and Ru in a total amount of 95 mass % or more with respect to the whole mass amount thereof, and the contents (Rh, Ru) of Rh and Ru (mass %) lie within an area which is surrounded by a line which connects point A (6, 1), point B (6, 15), point C (33, 18), point D (33, 4) and the point A (6, 1) in this order or lie on the line. The tip satisfies 1.5?Has/Han?2.2.

Abstract: A spark plug having an insulator that can be restrained from cracking in an environment of heating and cooling cycles. The spark plug includes an insulator having an axial bore extending in the direction of the axis, and a center electrode held in one end portion of the axial bore. The center electrode has an outer layer, and a core provided within the outer layer and formed from a material higher in thermal conductivity than the outer layer. After a heat treatment, the outer layer has a high-hardness region having a hardness of 190 Hv or higher and a thickness of 30 ?m to 200 ?m, and an element supply region having a thickness of 50 ?m or more.

Abstract: A spark plug having a center electrode; a ground electrode provided so as to form a gap between the ground electrode and the center electrode; and a tip provided on at least one of a distal end portion of the ground electrode and a front end portion of the center electrode, the end portions facing each other, characterized in that the tip contains an element group M (M consists of at least one species of Pt and Rh) in an amount of 3 mass % to 35 mass %, and an element group L (L consists of at least one species of Ir, Ru, and Pd) in an amount of 0 mass % to 15 mass %; the total amount of the element group M and the element group L is at most 35 mass %; and the total amount of Ni, the element group M, and the element group L is at least 94 mass %.

Abstract: A spark plug having a center electrode; a ground electrode provided so as to form a gap between the ground electrode and the center electrode; and a tip provided on at least one of a distal end portion of the ground electrode and a front end portion of the center electrode, the end portions facing each other, characterized in that the tip contains an element group M (M consists of at least one species of Pt and Rh) in an amount of 3 mass % to 35 mass %, and an element group L (L consists of at least one species of Ir, Ru, and Pd) in an amount of 0 mass % to 15 mass %; the total amount of the element group M and the element group L is at most 35 mass %; and the total amount of Ni, the element group M, and the element group L is at least 94 mass %.

Abstract: In a spark plug, at least either of a center electrode and a ground electrode has a tip which defines a gap, a tip provided on at least either of a center electrode and a ground electrode contains Ir, Rh and Ru in a total amount of 95 mass % or more with respect to the whole mass amount thereof, and the contents (Rh, Ru) of Rh and Ru (mass %) lie within an area which is surrounded by a line which connects point A (6, 1), point B (6, 15), point C (33, 18), point D (33, 4) and the point A (6, 1) in this order or lie on the line. The tip satisfies 1.5?Has/Han?2.2.

Abstract: A spark plug includes a ceramic insulator, a center electrode, a metallic shell, and a ground electrode. The center electrode has a shoulder portion at a forward end portion, which tapers forward with respect to the axial direction. A noble metal tip is joined to the forward end portion of the center electrode through a fusion zone. A spark discharge gap is formed between the noble metal tip and the ground electrode. The shortest distance between the fusion zone and a forward end surface of the noble metal tip is 0.8-1.2 mm. The outside diameter of the fusion zone as measured at a forward end of the fusion zone is smaller than that as measured at a rear end of the fusion zone. An acute angle ?1 formed by a straight line L1 and a straight line L2 satisfies the relational expression ?1?72°.

Abstract: A spark plug 100 has a center electrode tip 90, 95 at an end portion of an electrode. The electrode tip 90, 95 contains Pd as a main component in an amount greater than 40% by weight and contains at least one element of Ir, Ni, Co, and Fe such that Ir, if contained, is contained in an amount of 0.5% by weight to 20% by weight inclusive and at least one element of Ni, Co, and Fe, if contained, is contained in an amount of 0.5% by weight to 40% by weight inclusive on an element basis.

Abstract: A spark plug includes a ceramic insulator, a center electrode, a metallic shell, and a ground electrode. The center electrode has a shoulder portion at a forward end portion, which tapers forward with respect to the axial direction. A noble metal tip is joined to the forward end portion of the center electrode through a fusion zone. A spark discharge gap is formed between the noble metal tip and the ground electrode. The shortest distance between the fusion zone and a forward end surface of the noble metal tip is 0.8-1.2 mm. The outside diameter of the fusion zone as measured at a forward end of the fusion zone is smaller than that as measured at a rear end of the fusion zone. An acute angle ?1 formed by a straight line L1 and a straight line L2 satisfies the relational expression ?1?72°.

Abstract: An electrode tip located at an distal end of an electrode of a spark plug comprises Pd as a predominant component in an amount of 40 wt. % or more; at least one element of Ir, Ni, Co, and Fe, wherein, when the tip contains Ir, the amount of Ir is 0.5 wt. % to 20 wt. %, and when the tip contains at least one element of Ni, Co, and Fe, the amount of the at least one element is 0.5 wt. % to 40 wt. %; and at least one element of Pt, Re, Rh, and Ru in a total amount of 5 wt. % to 40 wt. %, wherein when the tip contains at least one element of Re, Rh, and Ru, the amount of the at least one element is 10 wt. % or less, and when the tip contains Pt, the amount of Pt is 16 wt. % to 40 wt. %. The electrode tip, which comprises Pd as the main component, has improved resistance to spark-caused wear and reduced occurrence of separation and cracking of the tip.

Abstract: A spark plug having an insulator that can be restrained from cracking in an environment of heating and cooling cycles. The spark plug includes an insulator having an axial bore extending in the direction of the axis, and a center electrode held in one end portion of the axial bore. The center electrode has an outer layer, and a core provided within the outer layer and formed from a material higher in thermal conductivity than the outer layer. After a heat treatment, the outer layer has a high-hardness region having a hardness of 190 Hv or higher and a thickness of 30 ?m to 200 ?m, and an element supply region having a thickness of 50 ?m or more.

Abstract: A spark plug 100 has a center electrode tip 90, 95 at an end portion of an electrode. The electrode tip 90, 95 contains Pd as a main component in an amount greater than 40% by weight and contains at least one element of Ir, Ni, Co, and Fe such that Ir, if contained, is contained in an amount of 0.5% by weight to 20% by weight inclusive and at least one element of Ni, Co, and Fe, if contained, is contained in an amount of 0.5% by weight to 40% by weight inclusive on an element basis.