Abstract: A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.

Abstract: A method for producing a bonded permanent magnet by additive manufacturing, comprising: (i) incorporating components of a solid precursor material into at least one deposition head of at least one multi-axis robotic arm of a big area additive manufacturing (BAAM) system, the components of the solid precursor material comprising a thermoplastic polymer and hard magnetic powder; said deposition head performs melting, compounding, and extruding functions; and said BAAM system has an unbounded open-air build space; and (ii) depositing an extrudate of said solid precursor material layer-by-layer from said deposition head until an object constructed of said extrudate is formed, and allowing the extrudate to cool and harden after each deposition, to produce the bonded permanent magnet. The resulting bonded permanent magnet and articles made thereof are also described.

Abstract: A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.

Abstract: This invention relates to a process for producing a non-pyrophoric, corrosion resistant rare earth-containing material capable of being formed into a polymer bonded permanent magnet comprising forming particles from a rare earth-containing alloy, and treating the alloy with a passivating gas comprised of nitrogen, carbon dioxide or a combination of nitrogen and carbon dioxide at a temperature below the phase transformation temperature of the alloy, and heat treating the alloy to produce material having a coercivity of at least 1,000 Oersteds. Rare earth-containing alloys suitable for use in producing magnets, such as Nd--Fe--B and Sm--Co alloys, can be used. If nitrogen is used as the passivating gas, the resultant powder particles have a nitrogen surface concentration of from about 0.4 to about 26.8 atomic percent. Moreover, if carbon dioxide is used as the passivating gas, the resultant powder particles have a carbon surface concentration of from about 0.02 to about 15 atomic percent.