In one aspect, the present disclosure provides a method for producing an aluminum platter, which can improve the smoothness of the substrate surface before a magnetic layer is formed thereon and can provide a hard disk substrate that can be processed into a medium with a high yield. In another aspect, the present disclosure relates to a method for producing an aluminum platter, including the following steps 1 and 2: step 1: bringing a composition containing a compound (component A) that has at least one structure represented by the following formula (I) and has a molecular weight between 50 and 100,000 inclusive into contact with a substrate surface of a NiP plated aluminum alloy substrate; and step 2: forming a magnetic layer on the substrate obtained in the step 1.

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A method is provided to remove a selective amount of material from a metal component fabricated by additive manufacturing in a self-terminating manner. The method can be used to remove support structures and trapped powder from a metal component as well as to smooth surfaces of a 3D printed metal component. In some embodiments, selected surfaces of the metal component are treated to make the selected surfaces at least one of mechanically and chemically unstable. The unstable portion of the metal support can then be removed chemically, electrochemically, or through vapor-phase etching. The method can be used for processing any fluid or vapor-accessible regions and surfaces of a 3D printed metal component.

A method is provided to remove a selective amount of material from a metal component fabricated by additive manufacturing in a self-terminating manner. The method can be used to remove support structures and trapped powder from a metal component as well as to smooth surfaces of a 3D printed metal component. In some embodiments, selected surfaces of the metal component are treated to make the selected surfaces at least one of mechanically and chemically unstable. The unstable portion of the metal support can then be removed chemically, electrochemically, or through vapor-phase etching. The method can be used for processing any fluid or vapor-accessible regions and surfaces of a 3D printed metal component.

An aluminum alloy article having improved surface contrast and an associated method are provided. The method includes grinding a surface of the article, diamond polishing the surface of the article, and removing -aluminum matrix material from the surface by fine polishing the surface with a suspension containing colloidal silica and a caustic substance, wherein the caustic substance has a higher pH value than the pH value of colloidal silica.

The present invention provides a composition for etching treatment of a resin material, the composition comprising an aqueous solution having a permanganate ion concentration of 0.2 mmol/L or more and a total acid concentration of 10 mol/L or more, and the aqueous solution satisfying at least one of the following conditions (1) to (3): (1) containing an organic sulfonic acid in an amount of 1.5 mol/L or more, (2) setting the divalent manganese ion molar concentration to 15 or more times higher than the permanganate ion molar concentration, and (3) setting the addition amount of an anhydrous magnesium salt to 0.1 to 1 mol/L. The composition for etching treatment of the present invention is a composition containing no hexavalent chromium and having excellent etching performance and good bath stability.

The present invention provides a composition for etching treatment of a resin material, the composition comprising an aqueous solution having a permanganate ion concentration of 0.2 mmol/L or more and a total acid concentration of 10 mol/L or more, and the aqueous solution satisfying at least one of the following conditions (1) to (3): (1) containing an organic sulfonic acid in an amount of 1.5 mol/L or more, (2) setting the divalent manganese ion molar concentration to 15 or more times higher than the permanganate ion molar concentration, and (3) setting the addition amount of an anhydrous magnesium salt to 0.1 to 1 mol/L. The composition for etching treatment of the present invention is a composition containing no hexavalent chromium and having excellent etching performance and good bath stability.