Dowa Mining Co., Ltd.

Hirofumi Takei

Kiyoshi Yamada

Masami Kamada

Toshinori Eba

Hiroshi Miyazawa

Kentaro Asai

Nobuo Otake

There is provided a tin-plated product which has a small deterioration of contact resistance with age, an excellent wear resistance and a low coefficient of friction. A coating of a composite material, which contains 0.1 to 1.0 wt % of carbon particles dispersed in a tin layer and which has a thickness of 0.5 to 10.0 &#x3bc;m, preferably 1.0 to 5.0 &#x3bc;m, is formed as the outermost layer of a substrate. Thus, the coefficient of dynamic friction between the tin-plated products of the same kind is 0.20 or less, and the coefficient of dynamic friction between the tin-plated product and a reflow tin-plated product is 0.20 or less, while the contact resistance is 1 m&#x3a9; or less.

Tin-plated product

A surface grinding machine for a sintered rare earth magnetic alloy wafer comprises a pair of disk-shaped grindstones that face each other across a prescribed gap to be rotatable in opposite directions about their center axes. The grinding surfaces of the pair of grindstones and the center axe inclination of one grinding stone are configured to form a planar grinding region A wherein a portion of both of the grinding surfaces of the pair of grindstones lie parallel with a constant intervening gap therebetween. Other portions of the grinding surfaces of the grindstones constitute a wedge-like opening region B that becomes more narrow toward the planar grinding surface A. A feeder to feed the wafers from the wedge-like opening region B toward the planar grinding region A is provided in order to grind both surfaces of the wafers at the planar grinding.

Sintered rare earth magnetic alloy wafer surface grinding machine

A method of producing a sintered rare earth magnetic alloy wafer comprises a step of using a cutter to slice a wafer of a thickness of not greater than 3 mm from a sintered rare earth magnetic alloy having ferromagnetic crystal grains surrounded by a more readily grindable grain boundary phase and a step of surface-grinding at least one cut surface of the obtained wafer with a grindstone to form at a surface layer thereof flat ferromagnetic crystal grain cross-sections lying parallel to the wafer planar surface. The method enables high-yield production of a sintered rare earth magnetic alloy wafer having flat surfaces.

Sintered rare earth magnetic alloy wafer and wafer surface growing machine

Method of producing sintered rare earth magnetic alloy wafer

When a work W is cut by moving a wire in an axial direction thereof while the wire is pressed onto the work and an abrasive liquid which is made by dispersing abrasive grains in a dispersion medium is interposed between the work and the wire, a flow of the wire is formed, and the wire is pressed onto the work while moving under the liquid level of the abrasive liquid whose flow is formed. The work is cut in the abrasive liquid so that a sufficient amount of the abrasive grains can be supplied between the work and the wire for a long time.

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Honjou, Japan

Hirofumi Takei