Abstract: A polishing composition for a substrate to be used for a memory hard disk, which comprises the following components (a) to (d): (a) water, (b) at least one compound selected from the group consisting of a polyoxyethylene polyoxypropylene alkyl ether and a polyoxyethylene polyoxypropylene copolymer, (c) at least one compound selected from the group consisting of nitric acid, nitrous acid, sulfuric acid, hydrochloric acid, molybdic acid, sulfamic acid, glycine, glyceric acid, mandelic acid, malonic acid, ascorbic acid, glutamic acid, glyoxylic acid, malic acid, glycolic acid, lactic acid, gluconic acid, succinic acid, tartaric acid, maleic acid and citric acid, and their salts, and (d) at least one abrasive selected from the group consisting of aluminum oxide, silicon dioxide, cerium oxide, zirconium oxide, titanium oxide, silicon nitride and silicon carbide.

Abstract: A polishing composition for a substrate to be used for a memory hard disk, which comprises the following components (a) to (d):

Abstract: A polishing composition for magnetic disk substrates to be used for memory hard disks, which comprises: (a) water; (b) at least one phosphate. compound selected from the group consisting of a phosphate ester of ethoxylated alkylalcohol and a phosphate ester of ethoxylated arylalcohol; (c) at least one polishing accelerator selected from the group consisting of an inorganic acid and an organic acid, and their salts, other than the phosphate compound of component (b); (d) at least one abrasive selected from the group consisting of aluminum oxide, silicon dioxide, cerium oxide, zirconium oxide, titanium oxide, silicon nitride and manganese dioxide.

Abstract: The invention intends to simplify the connecting operation of an insulated wire and a pin terminal, and to reduce the cost of connection. A spiral part of the insulated wire having a spiral end according to the invention is formed by removing an insulation at an end of the insulated wire to expose a conductor, and winding the exposed conductor into a spiral form by 1.5 folds or more to produce a spiral part. The insulated wire and the pin terminal are connected in such a manner that the pin terminal is inserted into the central opening of the spiral part, and the spiral part and the pin terminal are fixed with a fixing material, such as solder, or binding agent having a high conductivity. When a solder coating is formed on the conductor in the spiral part, it is possible to fix the spiral part and the pin terminal only by heating the spiral part to melt the coating solder.