Multilayered metal nano and micron particles
A sintering powder, wherein a least a portion of the particles making up the sintering powder comprise: a core comprising a first material; and a shell at least partially coating the core, the shell comprising a second material having a lower oxidation potential than the first material.
1. A sintering powder, wherein particles of the sintering powder comprise:
a core comprising a first material comprising copper; and
a shell at least partially coating the core, the shell comprising a layer of a second material having a lower oxidation potential than the first material, the second material comprising silver; and
a capping agent at least partially coating the shell, the capping agent comprising octylamine;
wherein the particles have a D50 of from 1 to 30 nm.
2. The sintering powder of claim 1 , wherein the particles have a D95 of less than 100 nm.
3. The sintering powder of claim 1 , wherein the particles have a D95 of from 0.1 to 10 μm.
4. The sintering powder of claim 1 , wherein the sintering powder comprises from 0.1 to 15 wt % capping agent.
5. The sintering powder of claim 1 , wherein the sintering powder comprises from 0.1 to 5 wt % capping agent.
6. The sintering powder of claim 1 , wherein the sintering powder comprises about 0.5 wt % capping agent.
7. The sintering powder of claim 1 further comprising a layer of a third material, wherein the third material is different from the second material.
8. A method of manufacturing the sintering powder of claim 1 , comprising:
(i) providing a solution comprising a reducing agent and particles containing a first material comprising copper;
(ii) reducing the concentration of the reducing agent in the solution from step (i);
(iii) contacting the solution from step (ii) with a source of a second material comprising silver, to at least partially coat at least some of the particles containing a first material with a layer of the second material, the second material having a lower oxidation potential than the first material; and
(iv) recovering at least some of the particles containing the first material coated with the second material from the solution of step (iii);
wherein the particles comprise:
a core comprising the first material comprising copper; and
a shell at least partially coating the core, the shell comprising a layer of the second material comprising silver; and
a capping agent at least partially coating the shell, the capping agent comprising octylamine;
wherein the particles have a D50 of from 1 to 30 nm.
9. The method of claim 8 , wherein step (i) comprises:
providing a solution comprising a source of first material; and
contacting the solution with a reducing agent.
10. The method of any of claim 8 , wherein the reducing agent comprises hydrazine and/or borohydride.
11. The method of claim 10 , wherein:
the reducing agent comprises hydrazine; and
step (ii) comprises contacting the reducing agent with acetone under basic conditions.
12. The method of claim 8 , wherein:
the first material comprises copper;
the second material comprises silver; and
the weight ratio of silver to copper in step (iii) is from 40:60 to 85:15.
13. The method of claim 8 , wherein the solution of step (i) comprises capping agent.
14. The method of claim 8 , wherein step (iv) comprises filtration and/or centrifugation.
15. A method of manufacturing a sintering powder comprising copper-containing nanoparticles coated with a layer comprising silver, the method comprising:
(i) providing a solution comprising a hydrazine reducing agent, a capping agent, and copper-containing nanoparticles;
(ii) contacting the solution from step (i) with hydroxide ions and acetone to reduce the concentration of the hydrazine reducing agent in the solution;
(iii) contacting the solution from step (ii) with a silver salt to at least partially coat at least some of the copper-containing nanoparticles with a layer comprising silver; and
(iv) recovering at least some of the copper-containing nanoparticles coated with the layer comprising silver from the solution of step (iii);
wherein the particles comprise:
a core comprising the first material comprising copper; and
a shell at least partially coating the core, the shell comprising a layer of the second material comprising silver; and
a capping agent at least partially coating the shell, the capping agent comprising octylamine;
wherein the particles have a D50 of from 1 to 30 nm.