Abstract: An alloy cast strip preparation method includes a melting process and a casting cooling process. The melting process includes controlling a power of an induction melting furnace to perform a cyclic heat treatment to completely melt an alloy raw material before a surface temperature of a melt obtained by melting the alloy raw material is raised to 1300° C., and, after the alloy raw material is melted, adjusting the power of the induction melting furnace to stabilize the surface temperature of the melt at a temperature in a range from 1400° C. to 1500° C. The casting cooling process includes performing casting cooling on the melt arranged on a surface of a rotary cooling roll to obtain an alloy cast strip while controlling a surface linear velocity of the rotary cooling roll to be from 1.5 m/s to 2.25 m/s.

Abstract: Disclosed herein is a method for manufacturing an R-T-B permanent magnet and the magnet made with the method. The method may include preparation of strip pieces by melting and casting, preparing coarse powder by hydrogen decrepitation of the strip pieces; milling the powder into fine powder; pressing the fine powder is pressed to form a compact, pre-sintering the compact in vacuum or inert gas, machining the pre-sintered block to a desired shape; and dispersing the heavy rare earth compound powder into an organic solvent to prepare a slurry and a second sintering step.

Abstract: An alloy cast strip includes grains having R2Fe14B-type compound as main phase, where R denotes a rare earth element, Fe denotes iron, and B denotes boron. The grains include non-columnar grains having an aspect ratio in a range from 0.3 to 2 and columnar grains having an aspect ratio equal to or larger than 3. A ratio of an area of the non-columnar grains to a total area of the grains is equal to or larger than 60% and a ratio of a number of the non-columnar grains to a total number of the grains is equal to or larger than 75%. A ratio of an area of the columnar grains to the total area of the grains is equal to or smaller than 15% and a ratio of a number of the columnar grains to the total number of the grains is equal to or smaller than 10%.

Abstract: Disclosed herein is a method for manufacturing an R-T-B permanent magnet and the magnet made with the method. The method may include preparation of strip pieces by melting and casting, preparing coarse powder by hydrogen decrepitation of the strip pieces; milling the powder into fine powder; pressing the fine powder is pressed to form a compact, pre-sintering the compact in vacuum or inert gas, machining the pre-sintered block to a desired shape; and dispersing the heavy rare earth compound powder into an organic solvent to prepare a slurry and a second sintering step.