Production method for rare-earth sintered magnet, and wet-molding device
AssigneeProterial, Ltd.
InventorTakashi Tsukada
Life of this patent
Estimating the term…
Abstract
The production method for a rare-earth sintered magnet according to the present disclosure comprises: a step for producing a molded article by compression-molding a slurry containing a rare-earth element-containing alloy powder and a dispersion medium using a wet-molding device; and a step for sintering the molded article. When the slurry is being poured into the inside of a space forming a cavity of the wet-molding device, a magnetic field is not applied. By pressing of the slurry, the dispersion medium contained in the slurry starts to be removed from the inside of the space.
Claims7
A method for producing a sintered rare-earth-based magnet, the method comprising the steps of:
- preparing a wet pressing apparatus including:
- a die having a through-hole,
- a lower punch movable upward and downward with respect to the die in a state where at least a tip of the lower punch is inserted into the through-hole, and
- an upper punch movable upward and downward with respect to the lower punch,
- wherein the upper punch has a bottom end having a plurality of discharge holes formed therein, the plurality of discharge holes allowing a liquid to pass therethrough;
- a top end of the lower punch and the bottom end of the upper punch form a cavity inside the through-hole;
- and a distance between the top end of the lower punch and the bottom end of the upper punch is shortened to decrease a volume of the cavity;
- preparing a slurry containing an alloy powder, containing a rare-earth element, and a dispersant;
- forming a space by an inner wall of the through-hole of the wet pressing apparatus and the top end of the lower punch of the wet pressing apparatus, and injecting the slurry into the space to fill the space with the slurry;
- closing the space by the bottom end of the upper punch to form the cavity filled with the slurry;
- shortening the distance between the bottom end of the upper punch and the top end of the lower punch in a state where a transverse magnetic field, in a direction perpendicular to a direction in which the lower punch is movable upward and downward, is applied to the cavity, and discharging the dispersant contained in the slurry through the plurality of discharge holes of the upper punch to produce a compact of the alloy powder;
- and
- sintering the compact, wherein
- while the slurry is injected into the space, no magnetic field is applied to the space and the space is temporarily or intermittently covered with a non-magnetic lid,
- before the transverse magnetic field is applied to the cavity, the non-magnetic lid is retracted from a position at which the non-magnetic lid covers the space, and
- the non-magnetic lid does not include a through-hole for introducing or discharging the slurry.
Dependencies are inferred from the claim text.