Abstract: A method for producing a sintered R-iron (Fe)-boron (B) magnet, the method including: (1) producing a sintered magnet R1-Fe—B-M, where R1 is neodymium (Nd), praseodymium (Pr), terbium (Tb), dysprosium (Dy), gadolinium (Gd), holmium (Ho), or a combination thereof; M is titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), gallium (Ga), calcium (Ca), copper (Cu), Zinc (Zn), silicon (Si), aluminum (Al), magnesium (Mg), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), tungsten (W), molybdenum (Mo), or a combination thereof; (2) removing oil, washing using an acid solution, activating, and washing using deionized water the sintered magnet, successively; (3) mixing a superfine terbium powder, an organic solvent, and an antioxidant to yield a homogeneous slurry, coating the homogeneous slurry on the surface of the sintered magnet; and (4) sintering and aging the sintered magnet.

Abstract: A method for preparing an R—Fe—B based sintered magnet. The method includes: 1) preparing a R1—Fe—B-M alloy, pulverizing the R1—Fe—B-M alloy to yield a R1—Fe—B-M alloy powder, adding a heavy rare earth powder of R2 or R2X and subsequently adding a lubricant to the R1—Fe—B-M alloy powder and uniformly stirring to form a mixture, where R1 being Nd, Pr, Tb, Dy, La, Gd, Ho, or a mixture thereof; M being Ti, V, Cr, Mn, Co, Ga, Cu, Si, Al, Zr, Nb, W, Mo, or a mixture thereof; R2 being at least one from Tb, Dy, and Ho; X being at least one from O, F, and Cl; 2) pressing the mixture obtained in step 1) to form a compact, and sintering the compact in a pressure sintering device in vacuum or in an inactive gas atmosphere to obtain a magnet; and 3) aging the magnet obtained in step 2).

Abstract: A method for preparing an R—Fe—B based sintered magnet, including: preparing a R1—Fe—B-M sintered magnet having a thickness of between 1 and 10 mm; spraying a layer of Tb or Dy having a thickness of between 10 and 200 ?m on each surface of the sintered magnet in a sealed box under an Ar atmosphere by hot spraying method; and transferring the sintered magnet coated with the layer of Tb or Dy to a vacuum sintering furnace, heating the sintered magnet at the temperature of between 750 and 1000° C. in a vacuum condition or under the Ar atmosphere, and allowing heavy rare earth element Tb or Dy to enter an inner part of the sintered magnet via grain boundary diffusion.

Abstract: A method for preparing an R—Fe—B based sintered magnet, including: preparing a R1—Fe—B-M sintered magnet having a thickness of between 1 and 10 mm; spraying a layer of Tb or Dy having a thickness of between 10 and 200 ?m on each surface of the sintered magnet in a sealed box under an Ar atmosphere by hot spraying method; and transferring the sintered magnet coated with the layer of Tb or Dy to a vacuum sintering furnace, heating the sintered magnet at the temperature of between 750 and 1000° C. in a vacuum condition or under the Ar atmosphere, and allowing heavy rare earth element Tb or Dy to enter an inner part of the sintered magnet via grain boundary diffusion.

Abstract: A method for preparing an R—Fe—B based sintered magnet. The method includes: 1) preparing a R1—Fe—B-M alloy, pulverizing the R1—Fe—B-M alloy to yield a R1—Fe—B-M alloy powder, adding a heavy rare earth powder of R2 or R2X and subsequently adding a lubricant to the R1—Fe—B-M alloy powder and uniformly stirring to form a mixture, where R1 being Nd, Pr, Tb, Dy, La, Gd, Ho, or a mixture thereof; M being Ti, V, Cr, Mn, Co, Ga, Cu, Si, Al, Zr, Nb, W, Mo, or a mixture thereof; R2 being at least one from Tb, Dy, and Ho; X being at least one from O, F, and Cl; 2) pressing the mixture obtained in step 1) to form a compact, and sintering the compact in a pressure sintering device in vacuum or in an inactive gas atmosphere to obtain a magnet; and 3) aging the magnet obtained in step 2).