Process for the Production of Nickel-Refractory Oxide Powders and Product Thereof (Patent No: 786268)

Inventor: Weizenbach, Bauke

Location: Fort Saskatchewan

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed, are defined as follows:

1. A process for producing nickel powder having discrete refractory oxide particles in integral association therewith which comprises: impregnating basic nickel carbonate particles with a controlled quantity of discrete sub-micron sized refractory oxide particles, reducing said impregnated basic nickel carbonate particles to elemental nickel by reacting a liquid suspension of said particles with hydrogen at a temperature above about 100°F. and under a partial pressure of hydrogen of at least about 50 p.s.i.

2. A process for producing nickel powder having discrete refractory oxide particles in integral association therewith which comprises forming an aqueous suspension of basic nickel carbonate particles impregnated v1ith a controlled quantity of submicron sized discrete refractory oxide particles, reacting the suspension with hydrogen at a temperature above about 100°F. and under a partial pressure of hydrogen of at least about 50 p.s,i,; continuing said reaction with hydrogen to reduce basic nickel carbonate to elemental nickel and collecting product powder,

3. A process for producing nickel powder having discrete refractory oxide particles in integral association therewith which comprises: forming a suspension of finely divided basic nickel carbonate in a liquid medium in which the basic nickel carbonate is substantially insoluble, adding insoluble sub-micron-sized refractory oxide particles to said suspension; agitating the suspension; reacting the suspension with hydrogen at a temperature above about 100°F, and under a partial pressure of hydrogen of at least about 50 pounds per square inch; continuing said reaction with hydrogen to reduce said basic nickel carbonate to elemental nickel and collecting product powder.

4. The process according to claims 1, 2 or 3 in which the reaction with hydrogen is carried out at a temperature in the range of from about 100°F. to about 500°F.

5. The process according to claims 1, 2 or 3 in which the reaction with hydrogen is carried out at a temperature in the range of from about 200°F. to about 350°F. under a partial pressure of hydrogen within the range of about 100 p.s.i. to about 500 p.s.i.

6. The process according to claims 1, 2 or 3, in which said refractory oxide is selected from the group consisting of thoria, yttria, ceria, magnesia, beryllia, zirconia, hafnia, silica, titania, alumina, uranium dioxide and lanthanum trioxide.

7. The process according to claims 1, 2 or 3, in which the reduction reaction is carried out in the presence of up to about 1 g.p.l. of a catalyst selected from the group consisting of anthraquinone, substituted anthraquinone, benzoquinone, naphthaquinone, ortho- and para-polyhydric phenols, tannic acid and morin.

8. A process for producing finely divided nickel powder having discrete sub-micron sized refractory oxide particles integrally associated therewith which comprises: forming a suspension of finely divided basic nickel carbonate in aqueous media; agitating said suspension and adding thereto water insoluble refractory oxide particles of a size below about 50 millimicrons, said refractory oxide having a melting point above the melting point of nickel and being thermally stable and substantially insoluble in nickel at elevated temperatures below the melting point of nickel; reacting said suspension with hydrogen in a closed reaction vessel at a temperature in the range of about 200°F. to about 450°F. under a partial pressure of hydrogen in the range of about 100 p.s.i. to about 500 p.s.i.; continuing said reaction with hydrogen to reduce said basic nickel carbonate to elemental nickel and separating and collecting product powder.

9. The process according to claim 8 in which the hydrogen reducing reaction is carried out at a temperature in the range of about 250°F. to about 350°F. in the presence of from about 0.02 to about 0.35 g.p.l. of anthraquinone.

10. The process according to claim 8 in which the refractory metal oxide consists of thoria particles of a size in the range of about 5 to about 30 millimicrons provided in amount equivalent to about 2 to about 4% by weight of nickel present in the suspension.

11. The process according to claim 10 in which the thoria is provided in the suspension in the form of a colloidal aquasol.

12. The process according to claims 8, 9 or 10 in which the basic nickel carbonate-water suspension is formed by boiling a nickel ammine carbonate solution to drive off ammonia and carbon dioxide and precipitate basic nickel carbonate.

13. A process for producing finely divided nickel-refractory oxide compositions suitable for use in powder metallurgical fabrication of dispersion strengthened nickel and nickel base alloy products which comprises the steps of: preparing nickel ammine carbonate solution containing up to about 100 grams per litre of nickel; boiling said solution to remove ammonia and carbon dioxide from said solution and precipitate basic nickel carbonate therefrom and produce a suspension of basic nickel carbonate in aqueous media; injecting into said suspension refractory oxide particles of a size below about 50 millimicrons in amount equivalent to up to 50% by weight of nickel present in said suspension, said oxide particles being formed of at least one oxide selected from the group consisting of thoria, ceria, yttria, silica, alumina, zirconia, hafnia, beryllia, titania, uranium dioxide, lanthanum trioxide and magnesia; agitating the so-formed basic nickel carbonate-refractory oxide suspension and reacting same in a closed reaction vessel with hydrogen at a temperature between about 250°F. and about 450°F. under a partial pressure of hydrogen between about 100 p.s.i. and about 500 p,s.i.; continuing said reaction to effect substantially complete reduction of basic nickel carbonate to elemental nickel and collecting product powder.

14. A process for producing finely divided nickel-refractory oxide compositions suitable for use in powder metallurgical fabrication of dispersion strengthened nickel and nickel base alloy products which comprises the steps of: preparing nickel ammine carbonate solution containing up to about 100, grams per litre of nickel; moiling said solution at atmospheric pressure by injection of steam thereinto to remove ammonia and carbon dioxide from
said solution and precipitate basic nickel carbonate therefrom and produce a suspension of basic nickel carbonate in aqueous media; continuing said boiling until the conductivity of said suspension is below about 500 micromhos per centimetre; injecting into said suspension refractory oxide particles of a size below about 50 millimicrons in amount equivalent to up to 50%, by weight of nickel present in said suspension, said oxide particles being formed of at least one oxide selected from the, group consisting of thoria, ceria, yttria, silica, alumina, zirconia, hafnia, beryllia, titania, uranium dioxide, lanthanum trioxide and magnesia; agitating the so-formed basic nickel carbonate-refractory oxide suspension and reaction same in a closed reaction vessel with hydrogen at a temperature between about 250°F. and about 450°F. under a partial pressure of hydrogen between about 100 p.s.i. and about 500 p.s.i.; continuing said reaction to effect substantially complete reduction of basic nickel carbonate to elemental nickel and collecting product powder.

15. The process according to claim 14 in which between about 0.02 and about 0.3 grams per litre of anthraquinone is provided in the basic nickel carbonate-refractory oxide suspension prior to treatment with hydrogen.

16. The process according to claims 13, 14 or 15 in which the refractory oxide is thoria of a size within the range of 10-30 millimicrons and is provided in amount equivalent to about 2.0 to about 4.0% by weight of nickel present in the suspension.

17. The process according to claims 13 or 14 in which the ammoniacal ammonium nickel carbonate solution is prepared by leaching nickel powder in an aqueous ammoniacal ammonium carbonate solution.

18. A nickel-refractory oxide powder composition suitable for fabrication of dispersion strengthened nickel and nickel base alloys which consists essentially of irregular-shaped particles of nickel, about 0.2 to about 0.5 microns in size, said particles occurring singly and in clusters up to 5.0 microns in size and said particles having firmly attached to their surfaces discrete refractory metal oxide particles of a size below about 50 millimicrons, said composition being non-pyrophoric in the as-produced state.

19. A nickel-refractory oxide powder composition suitable for fabrication of dispersion strengthened nickel and nickel base alloys which consists essentially of irregular-shaped particles of nickel, about 0.2 to about 0.5 microns in size, said particles occurring singly and in clusters up to 5.0 microns in size and said particles having firmly attached to their surfaces discrete refractory metal oxide particles of a size below about 50 millimicrons, said composition being obtained by direct hydrogen reduction of refractory-oxide impregnated basic nickel carbonate from aqueous media at temperatures below 500°F.

20. The composition of claims 18 or 19 wherein the refractory oxide is at least one member of the group consisting of thoria, yttria, ceria, alumina, zirconia, silica, beryllia, hafnia, titania, uranium dioxide, lanthanum trioxide and magnesiu and is present in amount equivalent to about 2.0 to about 4.0 volume percent of the nickel.

21. The composition of claims 18 or 19 in which the refractory oxide is thoria particles of a size in the range of about 10 to about 30 millimicrons.