Intermetallics Co.

Nagoya-shi, Japan

Intermetallics Co.

Nagoya-shi, Japan
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Patent
Intermetallics Co. and Daido Steel Co. | Date: 2017-04-05

The purpose of the present invention is to provide an RFeB system sintered magnet which has a high and uniform level of coercivity over the entirety of the single magnet even if the magnet is comparatively thick. The present invention is an RFeB system sintered magnet in which a heavy rare-earth element R^(H) which is at least one kind of rare-earth element selected from the group of Dy, Tb and Ho is diffused into a base material through the grain boundaries of the same base material made of a sintered compact of an RFeB system magnet containing R^(L), Fe and B, where R^(L) represents a light rare-earth element which is at least one kind of rare-earth element selected from the group of Nd and Pr, wherein: the size of the RFeB system sintered magnet at a smallest-size portion is greater than 3 mm; the amount of heavy rare-earth element R^(H) contained in the RFeB system sintered magnet divided by the volume of the RFeB system sintered magnet is equal to or greater than 25 mg/cm^(3); and the difference between a local coercivity at the surface of the smallest-size portion and a local coercivity in the central region of the smallest-size portion is equal to or less than 15 % of the local coercivity at the surface.


Patent
Intermetallics Co. | Date: 2017-06-28

The problem addressed by the present invention is to provide an RFeB system sintered magnet which does not contain a heavy rare-earth element R^(H) (Dy, Tb and Ho) in a practically effective amount and yet is suited for applications in which the magnet undergoes a temperature increase during its use. The RFeB system sintered magnet according to the present invention is an RFeB system sintered magnet containing at least one element selected from the group consisting of Nd and Pr as a rare-earth element R in addition to Fe and B while containing none of Dy, Tb and Ho, the magnet having a temperature characteristic value t_((100-23)) which satisfies -0.58


Patent
Intermetallics Co. | Date: 2016-12-19

Disclosed is a sintered NdFeB magnet having high coercivity (H_(cJ)) a high maximum energy product ((BH)_(max)) and a high squareness ratio (SQ) even when the sintered magnet has a thickness of 5 mm or more. The sintered NdFeB magnet is produced by diffusing Dy and/or Tb in grain boundaries in a base material of the sintered NdFeB magnet by a grain boundary diffusion process. The sintered NdFeB magnet is characterized in that the amount of rare earth in a metallic state in the base material is between 12.7 and 16.0% in atomic ratio, a rare earth-rich phase continues from the surface of the base material to a depth of 2.5 mm from the surface at the grain boundaries of the base material, and the grain boundaries in which R_(H )has been diffused by the grain boundary diffusion process reach a depth of 2.5 mm from the surface.


Patent
Intermetallics Co. | Date: 2016-02-03

The present invention addresses the problem of providing a sintered magnet production method capable of suppressing the growth of the particles of alloy powder during a sintering process. Provided is a sintered magnet production method including a filling process in which the cavity of a container is filled with an alloy powder of a raw material for a sintered magnet, an orienting process in which the alloy powder in the cavity is oriented by applying an magnetic field to the alloy powder without applying a mechanical pressure, and a sintering process in which the alloy powder oriented by the orienting process is sintered by heating the alloy powder without applying a mechanical pressure, the method being characterized in that: the median D_(50) of a particle size distribution of the alloy powder measured by a laser diffraction method is 3 m or less, and a powder of a high-melting-point material having a higher melting point than the heating temperature in the sintering process is mixed in the alloy powder before or in the filling process, where the median D_(50) of the powder of the high-melting-point material is 0.3 m or less.


Patent
Intermetallics Co. and Daido Steel Co. | Date: 2016-01-27

The present invention addresses the problem of providing a grain boundary diffusion treatment jig that does not easily become fused with a base material S an R^(L)_(2)Fe_(14)B system magnet having a surface coated with an adhesion material P containing an element R^(H) (which is at least one element selected from the group of Dy, Tb and Ho) when subjected to a heating process for grain boundary diffusion treatment. The grain boundary diffusion treatment jig 10 includes a plate-shaped base 11 having a surface with a number of projections 12 arranged so that the tips 121 of the projections 12 lie in one plane, and the surfaces of the tips 121 are made of a ceramic material. Since the contact area between the adhesion material applied to the surface of the base material and the grain boundary diffusion treatment jig is reduced by the use of the projections 12 for supporting the base material S, and since a ceramic material that does not easily react with the adhesion material P is used, the fusion of the base material S and the grain boundary diffusion treatment jig 10 is less likely to occur in the aforementioned heating process.


Patent
Intermetallics Co. and Daido Steel Co. | Date: 2016-01-27

The present invention addresses the problem of providing a method for easily producing an RFeB system sintered magnet having high coercivity and being capable of suppressing the influence of eddy current during a period of use while being composed of a plurality of unit sintered magnets strongly bonded together. It is a method for producing an RFeB system sintered magnet composed of at least two unit sintered magnets 11 bonded to each other at flat bonding surfaces, each unit sintered magnet composed of crystal grains whose main phase is made of R_(2)Fe_(14)B containing, as a main rare-earth element R, a light rare-earth element R_(L) which is at least one element selected from the group of Nd and Pr. A paste 12 prepared by mixing an organic matter and a metallic powder containing at least one element selected from the heavy rare-earth elements R_(H) of Dy, Ho and Tb is sandwiched between the mutually neighboring unit sintered magnets 11, and a grain boundary diffusion treatment is performed by performing a heating process, with the paste 12 in contact with each bonding surface. The coercivity is improved by this grain boundary diffusion treatment. Furthermore, since an oxide or similar compound of R_(H) and/or R_(L) is formed at the boundary of the unit sintered magnets 11, the influence of eddy current during a period of use is suppressed, and the unit sintered magnets 11 are strongly bonded together.


The present invention is aimed at providing a method for producing, with a high degree of orientation, an RFeB system sintered magnet with the main phase grains having a grain size of 1 m or less as well as a considerably equal grain size. A method for producing an RFeB system sintered magnet including the steps of preparing a shaped body oriented by a magnetic field and sintering the shaped body, wherein the shaped body is prepared using an alloy powder of an RFeB material having a particle size distribution with an average value of 1 m or less in terms of a circle-equivalent diameter determined from a microscope image, the alloy powder obtained by pulverizing coarse particles having fine crystal grain, each coarse particle having grains of the RFeB material formed inside, the crystal grains having a crystal grain size distribution with an average value of 1 m or less in terms of the circle-equivalent diameter determined from a microscope image, and 90 % by area or more of the crystal grains being separated from each other. Since this alloy powder is pulverized to individual grains, an RFeB system sintered magnet with a high degree of orientation can be produced.


Patent
Intermetallics Co. and Daido Steel Co. | Date: 2016-05-31

A powder-filling system capable of filling a container with powder at an approximately uniform filling density has: a hopper having an opening removably and hermetically closably attached to the container, the hopper communicating with the container at the opening for supplying powder to a container; a powder supplier for supplying powder to the hopper; a gas supplier for repeatedly supplying compressed gas in a pulsed form to the hopper, with the hopper hermetically closably attached to the container; and a sieve member provided at the opening and having a smaller openings in a region near a side wall of the hopper than in its central region. The smaller openings in the region near the side wall of the hopper where the powder more easily falls from the hopper into the container impedes the fall of the powder in that region and improves the overall uniformity in the filling density.


Patent
Intermetallics Co. | Date: 2016-11-09

The objective of the present invention is to provide a mold for making a NdFeB sintered magnet by processes of: filling an inside of the mold with a powder; orienting the powder inside the mold with a magnetic field; charging the whole mold into a sintering furnace; and heating the powder in the mold without applying any mechanical pressure to the powder to obtain a sintered compact of the NdFeB sintered magnet, wherein: at least a part of the mold is made of a carbon material, said part causing friction between the carbon material and the sintered component.


The present invention addresses the problem of providing a method for producing an RFeB system magnet with high coercivity by preventing a coating material from peeling off the surface of a base material during a grain boundary diffusion treatment. Provided is a method for producing an R^(L)_(2)Fe_(14)B system magnet which is a sintered magnet or a hot-deformed magnet containing, as the main rare-earth element, a light rare-earth element R^(L) which is at least one of the two elements ofNd and Pr, the method including the steps of: applying, to a surface of a base material M of the R^(L)_(2)Fe_(14)B system magnet, a coating material 10 prepared by mixing a silicone grease 11 and an R^(H)-containing powder 14 containing a heavy rare-earth element R^(H) composed of at least one element selected from the group of Dy, Tb and Ho; and heating the base material M together with the coating material. The silicone having a siloxane bond prevents the coating material 10 from peeling off the surface of the base material M during the heating process. The improved adhesion of the coating material 10 to the base material M facilitates transfer of R^(H) into the grain boundaries of the base material M, whereby the coercivity is increased.

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