Method of plating a bonded magnet and a bonded magnet carrying a metal coating
AssigneeKanegafuchi Kagaku Kogyo Kabushiki Kaisha
InventorsTakuji Nomura, Hiroshi Watanabe
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Abstract
A closely adherent metal coating having a uniform thickness and substantially free from pinholes is formed on the porous surface of a bonded magnet to improve its oxidation and corrosion resistance without lowering its magnetic properties. The coating is formed by electroplating from an aqueous solution not containing chlorine, and having a pH of 5 or above. More particularly, the solution contains mainly nickel sulfate, an electrolyte in the form of an organic acid salt not containing chlorine, and a basic electrolyte not containing chlorine, and forms a nickel coating on the magnet surface.
Claims10
A method of manufacturing a bonded magnet which comprises mixing and molding a powder of a magnetic material represented as R-T-B, where R stands for Nd or a mixture of Nd and another rare-earth element, and T stands for Fe or a mixture of Fe and a transition element, and a binder to form the bonded magnet;
- coating the magnet with a mixture of a resin and a powder of an electrically conductive material, and electroplating the coated magnet to form a metal coating thereon.
A method of manufacturing a bonded magnet which comprises mixing and molding a powder of a magnetic material represented as R-T-B, where R stands for Nd or a mixture of Nd and another rare-earth element, and T stands for Fe or a mixture of Fe and a transition element, with a resin and a powder of an electrically conductive material to form the bonded magnet, and electroplating the bonded magnet to form a metal coating thereon.
A method of manufacturing a bonded magnet which comprises mixing and molding a powder of a magnetic material represented as R-T-B, where R stands for Nd or a mixture of Nd and another rare-earth element, and T stands for Fe or a mixture of Fe and a transition element, with a binder consisting of a metal powder to form the bonded magnet, and electroplating the bonded magnet to form a metal coating thereon.
A coated bonded magnet comprising magnetic powder held together by a binder to form a bonded magnet and a plated, substantially pinhole-free nickel coating formed on the surface of the bonded magnet, wherein the nickel coating is formed at a pH of at least 5 and is substantially free of chlorine atoms or chloride ions.
Dependencies are inferred from the claim text.