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 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 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: A glow plug includes a sleeve secured by press-fitting to a housing with a ceramic heater held therein. A lead wire exposed from the heater is electrically connected to an inside surface of the sleeve to form a joint portion. The joint portion and a press-fit portion formed between the sleeve and the housing are offset in position relative to each other along an axial direction of the housing. The joint portion is thus kept free from the influence of a load or pressure applied during press-fitting operation to form the press-fit portion. A method of producing such glow plug is also disclosed.

Abstract: A glow plug and related manufacturing method are disclosed. The glow plug includes a heating section for heating a combustion chamber of an engine for promoting an ignition. The heating section includes a ceramic heating element developing a heat when applied with electric power, a ceramic insulating support body embedded with the heating element, and a pair of lead wires connected to the heating element and having terminal portions exposed to a surface of the insulating body. The heating element has a positive temperature coefficient of resistance and includes: (a) initial resistance R20 equal to or greater than 0.3? and equal to or less than 0.65?; (b) heating resistance R1200 equal to or greater than 0.7? and equal to or less than 1.3?; and (c) temperature coefficient of resistance R1200/R20 equal to or greater than 2.0 and equal to or less than 4.0.

Abstract: A glow plug includes a sleeve secured by press-fitting to a housing with a ceramic heater held therein. A lead wire exposed from the heater is electrically connected to an inside surface of the sleeve to form a joint portion. The joint portion and a press-fit portion formed between the sleeve and the housing are offset in position relative to each other along an axial direction of the housing. The joint portion is thus kept free from the influence of a load or pressure applied during press-fitting operation to form the press-fit portion. A method of producing such glow plug is also disclosed.