R-FE-B-based sintered magnet with low B content and preparation method therefor

A method for preparing an R—Fe—B-based sintered magnet with a low B content, containing an R2Fe14B-type main phase, the R being at least one rare earth element comprising Nd, wherein:

• the R—Fe—B-based sintered magnet comprises the following components:
• 28.5 wt %-31.5 wt % of R,
• 0.86 wt %-0.94 wt % of B,
• 0.2 wt %-1 wt % of Co,
• 0.2 wt %-0.45 wt % of Cu,
• 0.3 wt %-0.5 wt % of Ga,
• 0.02 wt %-0.2 wt % of Ti, and
• 61 wt %-69.5 wt % of Fe,
• the content of each of Dy, Tb, Gd, or Ho in R is 1 wt % or below, and
• the method comprises:
• preparing a molten raw material component liquid of the R—Fe—B-based sintered magnet at a cooling rate of 102° C./sec-104° C./sec into an alloy for the R—Fe—B-based sintered magnet;
• crushing the alloy by alloy hydrogen absorption;
• micro-pulverizing the crushed alloy into a fine powder;
• acquiring a formed body using a magnetic field forming method;
• sintering the formed body in a vacuum or inert gas at a temperature of 900° C.-1100° C.;
• and
• performing a heat treatment on the sintered formed body to acquire a product.