Abstract: In an electrochemical gas sensor (10), a first sensing element (21) is stored in a first storage portion (31). A moisture permeable film (24) is disposed in a first introduction inlet (31A) of the first storage portion (31). The moisture permeable film (24) substantially prevents a to-be-detected gas from permeating therethrough. A second sensing element (22) is disposed in a space into which water vapor and the to-be-detected gas contained in a target gas flow. In such a configuration, the electrochemical gas sensor (10) is capable of detecting a to-be-detected gas having a concentration of 0 or more and 1 ppm or less.

Abstract: A spark plug wherein least one of a center electrode and a 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 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: The object of the present invention is to provide a spark plug having a discharge portion formed of a noble-metal chip increased in the Ir content while reducing the content of expensive Rh, which can be restrained from generation of unusual wear in the form of eroding the circumferential side surface of the noble-metal chip and exhibits excellent wear resistance. In the present invention, the discharge portion (31) in the center electrode (3) side is formed of a noble-metal chip (31?) comprising an Ir-based alloy and the noble-metal chip (31?) contains 90% by weight or more of Ir as the main component and further contains 0.5% by weight or more of Rh and from 0.5 to 8% by weight of Ni, whereby the noble-metal chip (31?) [discharge portion (31)] can be ensured with good wear resistance, the generation of unusual wear which readily occurs on decreasing the Rh content can be prevented by the addition of Ni and in turn, a spark plug having high performance can be fabricated at a low cost.

Abstract: A spark plug having a center electrode 2 formed from an electrode base material 2n, which is made of an Ni alloy containing an alloy component (e.g., Cr) capable of forming an oxide semiconductor having a resistivity of negative temperature coefficient. Thus, a corrosion suppression layer originating from the components of the electrode base material is formed on the surface of a tip end portion of the insulator 3, so that corrosion (channeling) of the surface of the tip end portion of the insulator 3 due to creeping spark discharge can be effectively suppressed. In addition, when the constituent metal of the electrode base material 2n has a coefficient of thermal conductivity of 17 to 30 W/m·K, the heat transfer performance of the electrode is enhanced, so that durability against electrode consumption can be greatly improved.

Abstract: A spark plug of the present invention is made of an Ir alloy including a specific amount of (1) Rh, (2) Pt, or (3) Rh and Pt or Rh and Ru. The spark plug comprises tips for a center electrode and for a ground electrode that are each 0.6 to 1.8 mm in diameter and 0.2 to 0.7 mm in thickness and for an interlayer made of an Ir alloy including Ni of 40 mass % that has a diameter slightly larger or smaller than that of each tip for the center electrode and for the ground electrode and has a thickness of 0.1 to 0.6 mm. These tips can be manufactured according to the powder processing method, the dissolution method, and so on. The tip for the center electrode is joined to the end surface of the basic body of the center electrode, which is made of a Ni alloy (Inconel 600), according to laser welding. The tip for the interlayer and the tip for the ground electrode are brought into contact with a predetermined position of the ground electrode, and are joined while being pressed according to electric resistance welding.

Abstract: The object of the present invention is to provide a spark plug having a discharge portion formed of a noble-metal chip increased in the Ir content while reducing the content of expensive Rh, which can be restrained from generation of unusual wear in the form of eroding the circumferential side surface of the noble-metal chip and exhibits excellent wear resistance.

Abstract: A spark plug having a discharge portion formed of a noble-metal chip, the spark plug being capable of restraining wear observed on a slenderized discharge portion in particular. Discharge portion (31) includes noble-metal chip (31′). Dimension D is 0.3-0.8 mm; and H is 0.4-2 mm, where D (mm) is a diameter representing the outside diameter of the noble-metal chip, and H (mm) is a discharge portion thickness representing the shortest distance between the periphery of a discharge face (31t) and a corresponding end edge of a weld zone W where a center electrode (3) and the noble-metal chip (31′) are welded. Further, the noble-metal chip (31′) contains a predominant amount of Ir and 0.5-8% by weight Ni.

Abstract: A spark plug having a discharge portion formed of a noble-metal chip, the spark plug being capable of restraining wear observed on a slenderized discharge portion in particular. Discharge portion 31 includes noble-metal chip 31′. Dimension D is 0.3-0.8 mm; and H is 0.4-2 mm, where D (mm) is a diameter representing the outside diameter of the noble-metal chip, and H (mm) is a discharge portion thickness representing the shortest distance between the periphery of a discharge face 31t and a corresponding end edge of a weld zone W where a center electrode 3 and the noble-metal chip 31′ are welded. Further, the noble-metal chip 31′ contains a predominant amount of Ir and 0.5-8% by weight Ni.

Abstract: A spark plug of the present invention is made of an Ir alloy including a specific amount of (1)Rh, (2)Pt, or (3) Rh and Pt or Rh and Ru. The spark plug comprises tips for a center electrode and for a ground electrode that are each 0.6 to 1.8 mm in diameter and 0.2 to 0.7 mm in thickness and for an interlayer made of an Ir alloy including Ni of 40 mass % that has a diameter slightly larger or smaller than that of each tip for the center electrode and for the ground electrode and has a thickness of 0.1 to 0.6 mm. These tips can be manufactured according to the powder processing method, the dissolution method, and so on. The tip for the center electrode is joined to the end surface of the basic body of the center electrode, which is made of a Ni alloy (Inconel 600), according to laser welding. The tip for the interlayer and the tip for the ground electrode are brought into contact with a predetermined position of the ground electrode, and are joined while being pressed according to electric resistance welding.

Abstract: A spark plug having a center electrode 2 formed from an electrode base material 2n, which is made of an Ni alloy containing an alloy component (e.g., Cr) capable of forming an oxide semiconductor having a resistivity of negative temperature coefficient. Thus, a corrosion suppression layer originating from the components of the electrode base material is formed on the surface of a tip end portion of the insulator 3, so that corrosion (channeling) of the surface of the tip end portion of the insulator 3 due to creeping spark discharge can be effectively suppressed. In addition, when the constituent metal of the electrode base material 2n has a coefficient of thermal conductivity of 17 to 30 W/m·K, the heat transfer performance of the electrode is enhanced, so that durability against electrode consumption can be greatly improved.

Abstract: A twin-hull boat equipped with a pair of transverse hydrofoils 4 and 5 which are respectively secured to the bottom surface of twin-hull structures 3A and 3B adjacent the stem and stern. A pair of auxiliary wings 6A and 6B are installed opposite to each other at predetermined positions on the internal wall surfaces of the twin-hull structures 3A and 3B mutually facing the hull center line and at a predetermined height between the upper water line formed in the course of low-speed cruising and the lower water line formed in the course of high-speed cruising. The twin-hull boat incorporates a postural angle regulating device 15 to properly regulate the postural angle of the auxiliary wings 6A and 6B by causing them to pivot about a horizontal axis.