Magnetic Nanoparticles, Bulk Nanocomposite Magnets, and Production Thereof

Abstract

Provided herein are systems, methods, and compositions for magnetic nanoparticles and bulk nanocomposite magnets.

1 - 9 . (canceled) 
     
     
         10 . A process of forming a plurality of magnetic nanoparticles comprising:
 a. providing a powder with particles of a magnetic material having a first size;   b. dispersing the powder in a first solvent with a surfactant; and   c. ball milling the powder into a plurality of nanoparticles of the magnetic material having a second size.   
     
     
         11 - 21 . (canceled) 
     
     
         22 . The process of  claim 10 , wherein the first size is 1-45 μm and the second size is up to 50 nm. 
     
     
         23 . The process of  claim 10 , wherein the plurality of nanoparticles comprise elongated nanoparticles. 
     
     
         24 . The process of  claim 10 , wherein the powder is selected from one of FeO, Fe 2 O 3 , Fe 3 O 4 , Co, Fe, Ni, CoFe, NiFe, CoO, NiO, ferrites of formula MFe 2 O 3  where M is Co or Ni, FePt, CoPt, SmCo-based alloys including SmCo 5 , Sm 2 Co 17 , Sm 2 Co 7 , and SmCo 7 , and rare earth-FeB-based alloys of formula R 2 Fe 14 B where R is Nd or Pr. 
     
     
         25 . The process of  claim 24 , wherein the powder is a SmCo-based alloy. 
     
     
         26 . The process of  claim 10 , wherein the ball milling step includes a weight ratio of ball to powder of 10:1 to 2:1. 
     
     
         27 . The process of  claim 10 , wherein the amount of the surfactant is 5-20% of the weight of the powder. 
     
     
         28 . The process of  claim 10 , wherein the amount of the surfactant is 8-10% of the weight of the powder. 
     
     
         29 . The process of  claim 10 , wherein the surfactant comprises oleic acid, oleyl amine, erucic acid, and/or linoleic acid. 
     
     
         30 . The process of  claim 10  further comprising:
 d. dispersing the nanoparticles into a second solvent; and 
 e. separating the nanoparticles by a size selection process. 
 
     
     
         31 . The process of  claim 30 , wherein the separating step comprises spinning the nanoparticles dispersed in the second solvent to obtain a first supernatant and a first slurry and separating the first supernatant from the first slurry to obtain a plurality of nanoparticles with an average size distribution of 4 to 10 nm dispersed in the first supernatant. 
     
     
         32 . The process of  claim 31  further comprising
 a. washing the first slurry with a solvent; 
 b. dispersing the washed first slurry in a solvent; 
 c. statically settling down the dispersed solution of the washed first slurry for 2 to 5 hours; 
 d. spinning the settled down solution of the first slurry to obtain a second supernatant and a second slurry; and 
 e. separating the second supernatant from the second slurry to obtain a plurality of nanoparticles with an average size of 10 to 15 nm. 
 
     
     
         33 . The process of  claim 31  further comprising:
 a. washing the first slurry with a solvent; 
 b. dispersing the washed first slurry in a solvent; 
 c. statically settling down the dispersed solution of the washed first slurry for 20 to 30 minutes; 
 d. spinning the settled down solution of the first slurry to obtain a second supernatant and a second slurry; and 
 e. separating the second supernatant from the second slurry to obtain a plurality of nanoparticles with an average size greater than 20 nm.