The invention discloses a preparation method of high-
coercivity sintered Nd-Fe-B. The preparation method comprises the following steps: preparing a main phase
alloy powder and a
grain boundary phase
alloy powder; protecting the prepared main phase
alloy powder and the
grain boundary phase alloy powder by using
nitrogen or
argon in a protective medium, and uniformly mixing, wherein the
mass percent of the added
grain boundary phase alloy powder accounts for 0.1-10 percent; carrying out orientation profiling and cold isostatic pressing on the mixed alloy powder; in a
vacuum sintering furnace,
sintering a profiled
magnet block for 2-4h at the temperature of 1000-1100 DEG C, then carrying out primary
tempering for 2-4h at the temperature of 800-950 DEG C, and carrying out secondary
tempering for 2-4h at the temperature of 450-650 DEG C to prepare the sintered Nd-Fe-B. The invention also discloses the high-
coercivity sintered Nd-Fe-B. According to the preparation method disclosed by the invention, by virtue of
low melting point auxiliary alloy, the
wetting temperature between a grain boundary phase and a main phase is lowered, the
wetting time is prolonged, the utilization ratio of heavy
rare earth is increased, the used amount of
rare earth is lowered, the process is simple, the cost is low, and the high-
coercivity sintered Nd-Fe-B is suitable for
mass production.