Abstract: A friction stir welding apparatus includes a FSW tool that is held by a housing and welds to-be-welded members to each other by friction stir, and a gradual cooling device that gradually cools a weld site of the to-be-welded members welded by the FSW tool. The gradual cooling device is a contactless heat source that heats the weld site without coming into contact with the weld site. The contactless heat source is a high-frequency heat source.

Abstract: Provided is a piston for an internal combustion engine, the piston enabling both an improvement in heat efficiency and a reduction in emissions, and enabling the prevention of overheating of the piston to prevent the occurrence of knocking, pre-ignition, and a drop in air filling efficiency. This piston (100a) for an internal combustion engine constitutes a portion of a combustion chamber (9) of an internal combustion engine (200) and includes a substrate (103), a first film (101) provided on a section of the top surface of the substrate (103) contacting the combustion chamber (9), and a second film (102) provided on another section of the top surface. The piston for the internal combustion engine is characterized in that: the first film (101) has a lower heat conductivity and heat capacity than the substrate (103), and the second film (102) has a lower heat conductivity than the substrate (103) and a higher heat capacity than the first film (101).

Abstract: Provided are a heat-resistant member provided with a heat-shielding coating suitable for stable manufacturing and excellent in heat-insulating, thermoresponsive and distortion accommodating properties, and a method for manufacturing the same. The heat-shielding coating includes a metallic portion formed of agglomerates of a plurality of metal particles, and inorganic compound particles dispersed in the metallic portion. The metal particles are diffusion-bonded each other, and the metallic portion and a base material of the heat-resistant member are diffusion-bonded each other. The manufacturing method includes the steps of depositing mixed particles of the metal particles and the inorganic compound particles on a surface of the base material in a film shape; resistance-heating the mixed particles by current-passing while pressurized in a thickness direction; diffusion-bonding the metal particles each other; and the metallic portion and the base material each other.

Abstract: A piston for an internal combustion engine has a surface treatment portion on a piston base material at a piston crown surface, the surface treatment portion including, along the direction of depth from the surface side, a first layer that is comprised of a layer of a first metal or a layer containing the first metal, a second layer that contains both a second metal containing oxygen or an oxide of the second metal and a low-thermal-conductivity material, and a third layer that is comprised of a mixture of a third metal and the low-thermal-conductivity material.

Abstract: A friction stir welding apparatus includes a FSW tool that is held by a housing and welds to-be-welded members to each other by friction stir, and a gradual cooling device that gradually cools a weld site of the to-be-welded members welded by the FSW tool. The gradual cooling device is a contactless heat source that heats the weld site without coming into contact with the weld site. The contactless heat source is a high-frequency heat source.

Abstract: Provided are a heat-resistant member provided with a heat-shielding coating suitable for stable manufacturing and excellent in heat-insulating, thermoresponsive and distortion accommodating properties, and a method for manufacturing the same. The heat-shielding coating includes a metallic portion formed of agglomerates of a plurality of metal particles, and inorganic compound particles dispersed in the metallic portion. The metal particles are diffusion-bonded each other, and the metallic portion and a base material of the heat-resistant member are diffusion-bonded each other. The manufacturing method includes the steps of depositing mixed particles of the metal particles and the inorganic compound particles on a surface of the base material in a film shape; resistance-heating the mixed particles by current-passing while pressurized in a thickness direction; diffusion-bonding the metal particles each other; and the metallic portion and the base material each other.

Abstract: A friction stir welding method for welding a member to be welded, includes a step of heating the member to be welded by an applying heat source, a step of flattening a surface of the member to be welded that has been heated, by a smoothing component, and a step of performing friction stir welding to the surface of the member to be welded that has been flattened, by a rotating tool.