Intermetallics Co. | Date: 2013-03-08
A method for producing a sintered NdFeB magnet having high coercivity and capable of being brought into applications without lowering its residual magnetic flux density or maximum energy product and without reprocessing. The method includes applying a substance containing dysprosium (Dy) and/or terbium (Tb) to the surface of the sintered NdFeB magnet forming a base body and then heating the magnet to diffuse Dy and/or Tb through the grain boundary and thereby increase the coercivity of the magnet. This method is characterized in that: (1) the substance containing Dy or Tb to be applied to the surface of the sintered NdFeB magnet is substantially a metal powder; (2) the metal powder is composed of a rare-earth element R and an iron-group transition element T, or composed of R, T and another element X, the element X capable of forming an alloy or intermetallic compound with R and/or T; and (3) the oxygen content of the sintered NdFeB magnet forming the base body is 5000 ppm or lower. The element T may contain nickel (Ni) or cobalt (Co) to produce an anticorrosion effect.
Intermetallics Co. and Daido Steel Co. | Date: 2014-02-03
A sintered magnet production system using a press-less method capable of minimizing the distortion of a sintered magnet includes: a filling device for filling a container cavity with alloy powder for a sintered magnet; an orienting section for orienting the powder in the cavity by applying a magnetic field without applying a mechanical pressure to the powder; and a sintering section for sintering the powder oriented by the orienting section, by heating the powder without applying a mechanical pressure to the powder. The orienting section includes: an air-core coil; and two ferromagnetic members made of a ferromagnetic material arranged within the coil at respective open ends of the coil with a space for containing the container in between. The ferromagnetic members adjust the magnetic field within the coil toward a direction parallel to the axis of the coil, whereby distortion of a sintered magnet is minimized.
Intermetallics Co. | Date: 2013-03-26
The NdFeB system sintered magnet according to the present invention is a NdFeB system sintered magnet produced by diffusing Dy and/or Tb which are/is attached to a surface of a base material produced by orienting powder of a NdFeB system alloy in a magnetic field, and sintering the powder of the NdFeB system alloy, into grain boundaries inside the base material by grain boundary diffusion treatment, wherein a squareness ratio is equal to or higher than 95%. The NdFeB system sintered magnet can be produced by producing a base material of the NdFeB system sintered magnet by using a NdFeB system alloy with lamellas of a rare-earth rich phase dispersed substantially uniformly at predetermined spaces, as a starting alloy, and causing the alloy to occlude hydrogen, without performing heating for desorbing the occluded hydrogen thereafter until a sintering process, and applying grain boundary diffusion treatment to the base material.
Intermetallics Co. | Date: 2013-06-27
A method for producing a NdFeB system sintered magnet. The method includes: a hydrogen pulverization process, in which coarse powder of a NdFeB system alloy is prepared by coarsely pulverizing a lump of NdFeB system alloy by making this lump occlude hydrogen; a fine pulverization process, in which fine powder is prepared by performing fine pulverization for further pulverizing the coarse powder; a filling process, in which the fine powder is put into a filling container; an orienting process, in which the fine powder in the filling container is oriented; and a sintering process, in which the fine powder after the orienting process is sintered as held in the filling container. The processes from hydrogen pulverization through orienting are performed with neither dehydrogenation heating nor evacuation each for desorbing hydrogen occluded in the hydrogen pulverization process. The processes from hydrogen pulverization through sintering are performed in an oxygen-free atmosphere.
Intermetallics Co. | Date: 2014-06-27
A method for making a NdFeB sintered magnet, capable of enhancing the effect of increasing the coercive force and preventing the instability of the effects, and in addition, being inexpensive is provided. The method for making a NdFeB sintered magnet has processes of coating a NdFeB sintered magnet with a powder containing Dy and/or Tb, then heating the NdFeB sintered magnet, and thereby diffusing R