Claims
- 1. A method for converting metallic nanoparticles into larger, spherical metallic particles, comprising the steps of:
(a) generating an aerosol comprising solid metallic precursor nanoparticles entrained in plasma gas; (b) generating a non-oxidizing plasma from plasma gas, the plasma comprising a portion sufficiently hot to melt the solid metallic precursor nanoparticles; (c) directing the aerosol into the plasma and allowing the solid precursor metallic nanoparticles to melt, collide, join, and spheroidize to form larger molten, spherical, metallic particles; and (d) directing the molten, spherical, metallic microparticles away from the plasma so that they solidify and form larger, metallic, spherical, product particles.
- 2. The method of claim 1, wherein the precursor particles comprise Be, Mg, Ca, Sr, Ba, Ra, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Al, Ga, In, Sb, Pb, Te, Bi, lanthanide metals, actinide metals, or alloys thereof.
- 3. The method of claim 1, wherein the non-oxidizing plasma comprises argon plasma, helium plasma, xenon plasma, nitrogen plasma, neon plasma, hydrogen plasma, or mixtures thereof.
- 4. The method of claim 1, wherein the plasma comprises oxygen plasma or halogen plasma.
- 5. The method of claim 1, where the plasma is generated from plasma gas at a gas pressure of about 0.001-100 atmospheres.
- 6. The method of claim 5, wherein the plasma is generated from plasma gas at a pressure of about 1 atmosphere.
- 7. The method of claim 1, wherein the plasma is generated by supplying at least 50 Watts of power to the plasma gas.
- 8. The method of claim 7, wherein the plasma is generated by a DC discharge.
- 9. The method of claim 7, wherein the plasma is generated using radiofrequency energy.
- 10. The method of claim 9, wherein the plasma is generated using microwave energy.
- 11. The method of claim 10, wherein the plasma is generated using about 200-300 watts of power.
- 12. The method of claim 1, wherein the product particles have a diameter of about 0.5-1000 microns.
- 13. The method of claim 1, wherein the product metallic particles comprise spherical aluminum particles that have a diameter of about 0.5-3 microns.
STATEMENT REGARDING FEDERAL RIGHTS
[0001] This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention.