Provided are a CaMg.sub.2-based alloy hydride material for hydrolysis production of hydrogen, a preparation method therefor and a use thereof. The material has a general formula of CaMg.sub.xM.sub.yH.sub.z, wherein M is Ni, Co or Fe, 1.5≦x<2.0, 0<y≦0.5, and 3≦z<6. The preparation method for the material comprises the following steps: (1) stacking three pure metal block materials in a crucible, wherein a metal block material M is placed at the top; (2) installing the crucible in a high-frequency induction melting furnace, evacuating and introducing an argon gas; (3) starting the high-frequency induction melting furnace to heat at a low power first, then increasing the power to uniformly fuse same; and thereafter cooling with the furnace to obtain an alloy ingot, and hammer-milling to obtain a hydrogen storage alloy based on CaMg.sub.2; and (4) hydrogenating the hammer-milled hydrogen storage alloy to obtain the material for hydrolysis production of hydrogen. The preparation method is simple and low in cost. The material can absorb hydrogen at normal temperature with a good hydrogen absorption performance The prepared hydrogen is pure, and can be directly introduced into and used in a hydrogen fuel battery.

Provided are a CaMg.sub.2-based alloy hydride material for hydrolysis production of hydrogen, a preparation method therefor and a use thereof. The material has a general formula of CaMg.sub.xM.sub.yH.sub.z, wherein M is Ni, Co or Fe, 1.5≦x<2.0, 0<y≦0.5, and 3≦z<6. The preparation method for the material comprises the following steps: (1) stacking three pure metal block materials in a crucible, wherein a metal block material M is placed at the top; (2) installing the crucible in a high-frequency induction melting furnace, evacuating and introducing an argon gas; (3) starting the high-frequency induction melting furnace to heat at a low power first, then increasing the power to uniformly fuse same; and thereafter cooling with the furnace to obtain an alloy ingot, and hammer-milling to obtain a hydrogen storage alloy based on CaMg.sub.2; and (4) hydrogenating the hammer-milled hydrogen storage alloy to obtain the material for hydrolysis production of hydrogen. The preparation method is simple and low in cost. The material can absorb hydrogen at normal temperature with a good hydrogen absorption performance The prepared hydrogen is pure, and can be directly introduced into and used in a hydrogen fuel battery.

Disclosed are a rare-earth permanent magnet having improved magnetic properties and a method of manufacturing the same. A method of manufacturing a rare-earth permanent magnet may include: preparing a mixed powder including i) a first alloy represented by R1.sub.aR2.sub.bB.sub.cM.sub.dFe.sub.bal and ii) a second alloy represented by R2.sub.bB.sub.cM.sub.dFe.sub.bal where R1 is one or two or more of La, Ce, and Y; R2 is a rare-earth element except for La, Ce, and Y; and M is a metal element; press-forming and sintering the prepared mixed powder in a magnetic field to prepare a sintered body; and performing a heat treatment based on diffusion temperature conditions of an R1 component and an R2 component contained in the prepared sintered body.

Disclosed are a rare-earth permanent magnet having improved magnetic properties and a method of manufacturing the same. A method of manufacturing a rare-earth permanent magnet may include: preparing a mixed powder including i) a first alloy represented by R1.sub.aR2.sub.bB.sub.cM.sub.dFe.sub.bal and ii) a second alloy represented by R2.sub.bB.sub.cM.sub.dFe.sub.bal where R1 is one or two or more of La, Ce, and Y; R2 is a rare-earth element except for La, Ce, and Y; and M is a metal element; press-forming and sintering the prepared mixed powder in a magnetic field to prepare a sintered body; and performing a heat treatment based on diffusion temperature conditions of an R1 component and an R2 component contained in the prepared sintered body.

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.

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.

There is provided a compact for a magnet which can produce a magnetic member having high coercive force. The compact for a magnet is produced by compression-molding a rare earth-iron-based alloy powder containing a plurality of particles of a rare earth-iron-based alloy containing a rare earth element and iron, wherein the rare earth-iron-based alloy satisfies configurations (a) to (c) below and has 5% by volume or more and 20% by volume or less of voids formed therein. (a) Having a structure containing 10% by mass or more and 30% by mass or less of Sm, 10% by mass or less of Mn, and the balance consisting of Fe and inevitable impurities. (b) A composition, Sm.sub.2MN.sub.xFe.sub.17-x (x=0.1 or more and 2.5 or less). (c) An average crystal grain diameter of 700 nm or less.

A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr.sub.2Fe.sub.14B and Ho.sub.2Fe.sub.14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtains high coercivity.

Disclosed is a method of manufacturing a rare earth permanent magnet with substantially improved magnetic property. The method comprises: preparing a magnet master alloy by melting an R-T-B based alloy; pulverizing the magnet master alloy to provide a magnet powder; pressurizing the magnet powder as applying magnetic field to the magnet powder under an inert atmosphere to form a magnet molded body; sintering the magnet molded body under a vacuum atmosphere to obtain a sintered magnet molded body having oxygen content of about 0.1 wt % or less based on the total weight of the sintered magnet molded body; and treating the sintered magnet molded body with Dy and Tb.

Disclosed is a method of manufacturing a rare earth permanent magnet with substantially improved magnetic property. The method comprises: preparing a magnet master alloy by melting an R-T-B based alloy; pulverizing the magnet master alloy to provide a magnet powder; pressurizing the magnet powder as applying magnetic field to the magnet powder under an inert atmosphere to form a magnet molded body; sintering the magnet molded body under a vacuum atmosphere to obtain a sintered magnet molded body having oxygen content of about 0.1 wt % or less based on the total weight of the sintered magnet molded body; and treating the sintered magnet molded body with Dy and Tb.