Nanocrystalline cobalt doped nickel ferrite particles, method of manufacture, and uses thereof
Described herein is a nanocrystalline ferrite having the formula Ni 1−x−y M y Co x Fe 2+z O 4 , wherein M is at least one of Zn, Mg, Cu, or Mn, x is 0.01 to 0.8, y is 0.01 to 0.8, and z is −0.5 to 0.5, and wherein the nanocrystalline ferrite has an average grain size of 5 to 100 nm. A method of forming the nanocrystalline ferrite can comprise high energy ball milling.
1. A nanocrystalline ferrite having the formula
Ni 1−x−y M y Co x Fe 2+z O 4
wherein M is at least one of Zn, Mg, Cu, or Mn, x is 0.01 to 0.8, y is 0.01 to 0.8, and z is −0.5 to 0.5, and
wherein the nanocrystalline ferrite has an average grain size of 5 to 100 nm and the nanocrystalline ferrite is in the form of spherical particles with an average particle diameter of 0.2 to 100 micrometers.
2. The nanocrystalline ferrite of claim 1 , wherein the nanocrystalline ferrite has the formula Ni 1−x−y Zn y Co x Fe 2+z O 4 , wherein x is 0.1 to 0.3, y is 0.2 to 0.4, and z is −0.5 to 0.1.
3. The nanocrystalline ferrite of claim 1 , having at least one of a permeability of 1.5 to 5 at 0.1 to 6 gigahertz, or a permittivity of 3 to 8 at 0.1 to 6 gigahertz, wherein the permeability and permittivity are determined as a paraffin wax composite with 60 volume percent nanocrystalline ferrite based on the total volume of the paraffin wax composite.
4. A composite comprising:
the nanocrystalline ferrite of claim 1 and a polymer.
5. The composite of claim 4 , wherein the polymer comprises at least one of a fluoropolymer, a polyolefin, a poly(arylene ether ketone), a poly alkyl (meth)acrylate, or a poly(ether sulfone).
6. The composite of claim 4 , wherein the composite comprises 5 to 95 volume percent of the nanocrystalline ferrite based on the total volume of the composite; and 5 to volume percent of the polymer based on the total volume of the composite.
7. The composite of claim 4 , wherein the composite has at least one of
a permeability at 1 to 3 gigahertz of greater than or equal to 2;
a magnetic loss tangent at 1 to 3 gigahertz of less than or equal to 0.05;
a permittivity at 0.1 to 6 gigahertz of less than or equal to 3;
a dielectric loss tangent at 0.1 to 6 gigahertz of less than or equal to 0.02; or
a resonance frequency of 1 to 6 gigahertz;
wherein the respective properties are determined using a Vector Network Analyzer (VNA) with a coaxial line in a Nicholson-Ross-Weir method, in a frequency range of 0.1 to 8.5 gigahertz.
8. The composite of claim 4 , wherein the composite has
a magnetic loss tangent at 1 to 3 gigahertz of less than or equal to 0.05, and
a permeability at 1 to 3 gigahertz of greater than or equal to 3.
9. An article comprising the composite of claim 4 .
10. The article of claim 9 , wherein the article is an antenna, a transformer, an anti-electromagnetic interface material, or an inductor.
11. The nanocrystalline ferrite of claim 1 , wherein the nanocrystalline ferrite is in the form of
platelet shaped particles with planar dimensions of 0.5 to 100 micrometers and a thickness of 0.05 to 1 micrometer.
12. The article of claim 9 , wherein the article is a microwave device.
13. A nanocrystalline ferrite having the formula
Ni 1−x−y M y Co x Fe 2+z O 4
wherein M is at least one of Zn, Mg, Cu, or Mn, x is 0.01 to 0.8, y is 0.01 to 0.8, and z is −0.5 to 0.5, and
wherein the nanocrystalline ferrite has an average grain size of 5 to 100 nm and the nanocrystalline ferrite is in the form of spherical particles with an average particle diameter of 0.2 to 100 micrometers, and
wherein the nanocrystalline ferrite comprises a non-stoichiometric amount of Fe.
14. A method of forming the nanocrystalline ferrite of claim 1 , comprising:
high energy ball milling at least one of Ni, M, Co, and Fe precursor powders or a mixed powder having a nickel ferrite phase for a time and at a temperature sufficient to provide an as-milled powder having a nickel ferrite phase, and
heating the as-milled powder for a time and at a temperature sufficient to produce the nanocrystalline ferrite having a nanocrystalline structure with an average grain size of 5 to 100 nanometers.
15. The method of claim 14 , comprising:
prior to the high energy ball milling, mixing and heating of Ni, M, Co, and Fe precursor powders for a time and at a temperature sufficient to provide the mixed powder having a nickel ferrite phase.
16. The method of claim 14 , wherein the nanocrystalline ferrite has the formula Ni 1−x−y Zn y Co x Fe 2+z O 4 , wherein x is 0.1 to 0.3, y is 0.2 to 0.4, and z is −0.5 to 0.1.
17. The method of claim 14 , wherein the precursor powders comprise α-Fe 2 O 3 , NiO, Co 3 O 4 , or ZnO.
18. The method of claim 14 , wherein the ball to total powder mass ratio during the high energy ball milling is 20:1 to 40:1 and the ball has diameter of 3 mm to 20 mm.
19. The method of claim 14 , wherein the heating is done in at least one of air, argon, nitrogen, or oxygen.
20. The method of claim 14 , wherein the nanocrystalline ferrite has a permeability of 1.5 to 5 at 0.1 to 6 GHz, and/or a permittivity of 3 to 8 at 0.1 to 6 GHz, wherein the permeability and permittivity are determined as a paraffin wax composite with 60 volume percent nanocrystalline ferrite based on the total volume of the paraffin wax composite.