Abstract: The purposes of the present invention are to provide a substrate for a magnetic disk and a disk capable of maintaining long-term reliability of a hard disk while dealing with an increase in capacity of the hard disk and to provide a manufacturing method by which a magnetic disk (substrate therefor) having the above-mentioned characteristic can be manufactured. The present invention pertains to: a magnetic disk (substrate therefor) having a pair of main surfaces, wherein a 0.4 to 5.0 mm cutoff wavelength of at least one of the main surfaces of the magnetic disk (substrate therefor) at 25° C. after a predetermined thermal shock test has long wavelength waviness Wa of 2.0 nm or less, especially 0.5 to 2.0 nm, and a 0.08 to 0.45 mm cutoff wavelength thereof has short wavelength waviness ?Wa of 0.15 nm or less, especially 0.05 to 0.15 nm; and a manufacturing method thereof.

Abstract: A magnetic disk substrate having a pair of front and back principal surfaces, containing fixed portions that are in contact with fixing jigs when the magnetic disk substrate configured as a magnetic disk is incorporated in a hard disk device on the respective front and back principal surfaces, wherein a root mean square deviation Rq of surface roughnesses of the fixed portions on the respective front and back principal surfaces is from 0.01 to 0.44 ?m.; and a magnetic disk using the same.

Abstract: An aluminum alloy sheet material for a lithium-ion battery can significantly reduce the number of welding defects (e.g., bead non-uniformity and underfill) that occur during laser welding. The aluminum alloy sheet material includes 0.8 to 1.5 mass % of Mn, 0.6 mass % or less of Si, 0.7 mass % or less of Fe, 0.2 mass % or less of Cu, and 0.2 mass % or less of Zn, with the balance being Al and unavoidable impurities, Al—Mn—Si-based intermetallic compounds having a maximum length of less than 1.0 ?m being distributed in a matrix of the aluminum alloy sheet material in a number equal to or larger than 0.25 per ?m2, and the area ratio of the intermetallic compounds being 3.0% or more when a field of view having an area of 5000 ?m2 is subjected to image analysis.

Abstract: An aluminum alloy sheet material for a lithium-ion battery can significantly reduce the number of welding defects (e.g., bead non-uniformity and underfill) that occur during laser welding. The aluminum alloy sheet material includes 0.8 to 1.5 mass % of Mn, 0.6 mass % or less of Si, 0.7 mass % or less of Fe, 0.2 mass % or less of Cu, and 0.2 mass % or less of Zn, with the balance being Al and unavoidable impurities, Al—Mn—Si-based intermetallic compounds having a maximum length of less than 1.0 ?m being distributed in a matrix of the aluminum alloy sheet material in a number equal to or larger than 0.25 per ?m2, and the area ratio of the intermetallic compounds being 3.0% or more when a field of view having an area of 5000 ?m2 is subjected to image analysis.