Sumitomo Special Metals Co., Ltd.

Hitachi Metals, Ltd.

Masao Noumi

Osamu Yamashita

Tomoori Odaka

Hideyuki Morimoto

Ken Makita

Tsunekazu Saigo

Nobuhiro Sadatomi

First, an R&#x2014;Fe&#x2014;B based rare-earth sintered magnet body including, as a main phase, crystal grains of an RFeB type compound that includes a light rare-earth element RL, which is at least one of Nd and Pr, as a major rare-earth element R is provided. Next, an M layer, including a metallic element M that is at least one element selected from the group consisting of Al, Ga, In, Sn, Pb, Bi, Zn and Ag, is deposited on the surface of the sintered magnet body and then an RH layer, including a heavy rare-earth element RH that is at least one element selected from the group consisting of Dy, Ho and Tb, is deposited on the M layer. Thereafter, the sintered magnet body is heated, thereby diffusing the metallic element M and the heavy rare-earth element RH from the surface of the magnet body deeper inside the magnet.

R-F	e-B rare-earth sintered magnet and process for producing the same

R-Fe-B rare-earth sintered magnet and process for producing the same

A thermoelectric conversion material is formed of a polycrystal structure of crystal grains composed of a silicon-rich phase, and an added element-rich phase in which at least one type of added element is deposited at the grain boundary thereof, the result of which is an extremely large Seebeck coefficient and low thermal conductivity, allowing the thermoelectric conversion rate to be raised dramatically, and affording a silicon-based thermoelectric conversion material composed chiefly of silicon, which is an abundant resource, and which causes extremely low environmental pollution.

Thermoelectric conversion material and method of producing the same

Manufacture by rolling silicon steel having a silicon content of 3 wt % or greater and by rolling thin sendust sheet is implemented by powder metallurgical fabrication using powder as the starting raw material, and the average crystal grain size of the sheet-form sintered body or quick-cooled steel sheet is made 300 pm or less, whereby intra-grain slip transformation occurs after slip transformation in the grain boundaries, wherefore cold rolling is rendered possible. In addition, a mixture powder wherein pure iron powder and Fe&mdash;Si powder are mixed together in a prescribed proportion is fabricated with a powder metallurgy technique, and an iron-rich phase is caused to remain in the sintered body, whereby cold rolling is possible using the plastic transformation of those crystal grains. Furthermore, when a minute amount of a non-magnetic metal element such as Ti, V, or Al, etc., is added beforehand, it becomes easy to make the iron-rich phase and silicon-rich phase enter into solid solution during annealing, crystal grain growth can be promoted, the magnetic properties of the fabricated steel sheet become roughly equivalent to those of conventional ingot material, and silicon steel sheet exhibiting outstanding magnetic properties can be fabricated.

Method for producing high silicon steel, and silicon steel

A forming apparatus comprises a die formed with a through hole for provision of a cavity. A feeder box stored with a raw material powder having an average grain diameter of 0.1 &mgr;m&tilde;500 &mgr;m is positioned above the cavity of the die, and the raw material powder is allowed to fall into the cavity while an inside of the feeder box and an inside of the cavity are each maintained at a pressure not greater than 10 kPa. During the supply of the raw material powder, the feeder box may be vibrated, or the supply may be made via a hose. The raw material powder may be a granulated powder or a rare-earth alloy powder. The raw material powder supplied in the cavity is pressed by an upper punch and a lower punch into a compact.

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Kawanishi, Japan

Masao Noumi