Hitachi Metals, Ltd.

Neomax Co., Ltd.

Sumitomo Special Metals Co., Ltd.

Nobuhiro Misumi

Yoshimi Tochishita

Takeshi Nishiuchi

Atsushi Kikugawa

Koshi Yoshimura

Masanao Kamachi

Kazuaki Okuno

Ikuo Shimamoto

An object of the present invention is to provide an R&#x2014;Fe&#x2014;B based sintered magnet that exhibits excellent corrosion resistance and maintains excellent adhesion strength to an adherend even under severe conditions, and a method for producing the same. A corrosion-resistant magnet of the present invention as a means for achieving the object is characterized by comprising a chemical conversion film containing at least Zr, V, Al, fluorine, and oxygen as constituent elements and not containing phosphorus over a surface of an R&#x2014;Fe&#x2014;B based sintered magnet with a film made of Al or an alloy thereof therebetween.

Corrosion-resistant magnet and method for producing the same

An R&#x2014;Fe&#x2014;B sinlered magnet having on the surface thereof a vapor deposited film of aluminum or an alloy thereof and a method for producing the same. The vapor deposited film of aluminum or an alloy thereof comprises a columnar crystalline structure grown broader from the surface of the R&#x2014;Fe&#x2014;B sintered magnet body outward to the outer surface, which has a part within a region defined in the thickness direction of the film as taken from the surface of the R&#x2014;Fe&#x2014;B sintered magnet to &#x2153; of the film thickness, 5 to 30 intercrystalline gaps of 0.01 &#x3bc;m to 1 &#x3bc;m in width as counted per 10 &#x3bc;m length in the lateral direction of the film. The method comprises controlling the average film formation rate such that it is slower up to a predetermined point and then is speeded up later thereon.

R-Fe-B based sintered magnet having on the surface thereof vapor deposited film of aluminum or alloy thereof, and method for producing the same

A process for treating surfaces of rare earth metal-based permanent magnets, comprising removing an oxide layer formed on a surface of each of the permanent magnets using a blasting apparatus. The apparatus comprises a tubular barrel formed of a mesh net for accommodation of work pieces and supported circumferentially outside a center axis of a support member rotatable about the center axis, and an injection nozzle disposed to inject a blast material against the work pieces from the outside of the tubular barrel, wherein at least one of the tubular barrel and the support member is detachably mounted. The process further comprises removing the tubular barrel or the support member from the blasting apparatus and attaching the tubular barrel or the support member to a vapor deposited film forming apparatus, where a metal film is formed on the surface of each of the permanent magnets by a vapor deposition process.

Method for treating surfaces of rare earth metal-based permanent magnets

A dry surface treating apparatus of the present invention comprises, within a treating chamber, a surface-treating material supply section and a tubular barrel having a porous peripheral surface for accommodating a work piece, to treat a surface of the work piece while rotating the tubular barrel horizontally arranged about a horizontal rotational axis, wherein the tubular barrel has a slide stop for stopping a slide of the accommodated work piece along an inner peripheral surface of the tubular barrel due to rotation of the tubular barrel. According to the dry surface treating apparatus of the invention, because the work piece is inverted of surfaces within the tubular barrel, the time the work piece at each surface faces the surface-treating material supply section is made equivalent. Consequently, it is possible to provide even deposited-film formation or surface treatment to the opposite surfaces of a work piece, particularly, a rare earth metal-based permanent magnet in a plate or bow form.

Dry surface treating apparatus and dry surface treating method using the same apparatus

With the blasting apparatus in which the injection nozzle is disposed to inject the blast material against the work pieces from the outside of the tubular barrel formed of the mesh net for accommodation of the work pieces and rotatable about the center axis, the work pieces can be stirred homogenously and efficiently without excessive occurrence of the collision of the work pieces against one another and without occurrence of the collision of the work pieces against one another and with a strong shock force. Therefore, the treating efficiency is enhanced and, it is possible to inhibit the occurrence of the cracking and breaking of the work pieces. Further, with the blasting apparatus in which the tubular barrel is supported circumferentially outside the center axis of the support member rotatable about the center axis, it is possible to more inhibit the occurrence of the cracking and breaking of the work pieces.

Growing community of inventors

Hyogo, Japan

Nobuhiro Misumi