Tantalum metal powder

Claim 3

A method as defined in claim 1 in which the pre-agglomeration temperature lies in a range of 1100° to 1300° C., the second agglomeration temperature lies in a range of 1375° to 1425° C., and the final agglomeration temperature lies in a range of 1450° to 1500° C.

Claim 4

A high purity agglomerated tantalum powder as produced by the method of claim 1.

Claim 7

A method as defined in claim 4 in which the pre-agglomeration temperature lies in a range of 1100° to 1300° C., the second agglomeration temperature lies in a range of 1375° to 1425° C., and the final agglomeration temperature lies in a range of 1450° to 1500° C.

Claim 8

A high-purity agglomerated powder as produced by the method of claim 4.

Claim 11

An improved, high-purity agglomerated powder for use in the making of pressed and sintered anodes which typically comprises: a. tantalum agglomerated powder having in a screen test the following consistency: +80 Mesh -- 37.3% -80 + 200 Mesh -- 13.1% -200 + 325 Mesh -- 5.7% -325 Mesh -- 43.9% b. having a Fisher sub-sieve size of 9.6 microns, c. having a Scott density of 65.7 g/in 3 , and d. having a green strength of 10 pounds or greater on 2-gram, 0.261 inch diameter parts compacted to a green density of 7.0 grams per cubic centimeter and crushed by applying force on the parts laid sideways.

Claim 12

An improved, high-purity agglomerated powder for use in the making of pressed and sintered anodes which typically comprises: a. tantalum agglomerated powder having in a screen test the following consistency: +80 Mesh -- 37.3% -80 + 200 Mesh -- 13.1% -200 + 325 Mesh -- 5.7% -325 Mesh -- 43.9% b. having a Fisher sub-sieve size of 9.6 microns, c. having a Scott density of 65.7 g/in 3 , and d. having a green strength of 10 pounds or greater on 2-gram, 0.261 inch diameter parts compacted to a green density of 7.0 grams per cubic centimeter and crushed by applying force on the parts laid sideways.

Claim 13

An agglomerated tantalum powder produced by the process of claim 7 having a green strength of at least 10 pounds on 2-gram, 0.261 inch diameter parts connected to a green density of 7.0 grams per cubic centimeter and crushed by applying force on the parts laid sideways.

Claim 14

An agglomerated tantalum powder produced by the process of claim 7 having a green strength on 2-gram, 0.261 inch diameter parts of: a. at least 10 pounds when compacted to a green density of 7.0 grams per cubic centimeter, b. at least 20 pounds when compacted to a green density of 7.5 grams per cubic centimeter, c. at least 30 pounds when compacted to a green density of 8.0 grams per cubic centimeter, and d. crushed by applying force on the parts laid sideways.

Claim 15

An agglomerated tantalum powder produced by the process of claim 7 having a green strength on 2-gram, 0.261 inch diameter parts of: a. an average of about 14 pounds when compacted to a green density of 7.0 grams per cubic centimeter, b. an average of about 26 pounds when compacted to a green density of 7.5 grams per cubic centimeter, c. an average of about 43 pounds when compacted to a green density of 8.0 grams per cubic centimeter, and d. crushed by applying force on the parts laid sideways.

Claim 16

An agglomerated tantalum powder of claim 8 having an average green strength of about 18 pounds on 2-gram, 0.261 inch diameter parts compacted to a density of 7.0 grams per cubic centimeter and crushed by applying force on the parts laid sideways.

Claim 17

An agglomerated tantalum powder produced by the process of claim 7 having a specific capacitance expressed in microfarad-volts per gram (CV/g) as typically defined by the relationship: CV/g = 4.625T + 12,261 where T is the sintering temperature in °C. over the temperature range of 1800° to 2000° C., said capacitance determined on anodes pressed from the powder to a green density of 7.2 grams per cubic centimeter, sintered for 30 minutes at temperature, anodized in a solution of 0.01% phosphoric acid at 200 volts for those anodes sintered at 1800° C. and at 270 volts for those anodes sintered at 2000° C., and tested for specific capacitance in a solution of 10% phosphoric acid.

Claim 18

An agglomerated tantalum powder of claim 8 having a specific capacitance of about: a. 3900 CV/g for anodes sintered for 30 minutes at 1800° C., and b. 3000 CV/g for anodes sintered for 30 minutes at 2000° C., on c. anodes pressed from the powder to a green density of 7.2 grams per cubic centimeter, sintered for 30 minutes at temperature, anodized in a solution of 0.01% phosphoric acid at 200 volts for anodes sintered at 1800° C. and 270 volts for those anodes sintered at 2000° C., and tested for specific capacitance in a solution of 10% phosphoric acid.

Claim 19

An agglomerated tantalum powder of claim 8 having a dissipation factor of about: a. 15% for anodes sintered for 30 minutes at 1800° C., and b. 11% for anodes sintered for 30 minutes at 2000° C., on c. anodes pressed from the powder to a green density of 7.2 grams per cubic centimeter, sintered for 30 minutes at temperature, anodized in a solution of 0.01% phosphoric acid at 200 volts for those anodes sintered at 1800° C. and 270 volts for those anodes sintered at 2000° C., and tested for dissipation factor in a solution of 10% phosphoric acid.

Claim 20

A process for the production of an improved, high-purity agglomerated tantalum powder which comprises: a. subjecting high-purity tantalum metal, consolidated by melting, to a hydrogen atmosphere to produce a friable mass, b. milling the hydrided mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, g. milling the re-agglomerated porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggregates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.

Claim 21

A process for the production of an improved, high-purity agglomerated tantalum powder which comprises: a. subjecting high-purity tantalum metal, consolidated by melting, to a hydrogen atmosphere to produce a friable mass, b. milling the hydrided mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, g. milling the re-agglomerated porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggregates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.

Claim 22

An agglomerated powder of the hydride forming metals of Group IVB, comprising titanium, zirconium and hafnium, and Group VB, comprising vanadian and columbium produced by: a. subjecting the metal to a hydrogen atmosphere to produce a friable mass, b. milling the hydride mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggregates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.

Claim 23

An agglomerated powder of the hydride forming metals of Group IVB, comprising titanium, zirconium and hafnium, and Group VB, comprising vanadian and columbium produced by: a. subjecting the metal to a hydrogen atmosphere to produce a friable mass, b. milling the hydride mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggregates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.

Claim 24

A process for producing high green strength, agglomerated powder of the hydride forming metals of Group IVB, comprising titanium, zirconium and hafnium and Group VB, comprising vanadium and columbium produced by: a. subjecting the metal to a hydrogen atmosphere to produce a friable mass, b. milling the hydride mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, g. milling the re-agglomeration porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggreates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.

Claim 25

A process for producing high green strength, agglomerated powder of the hydride forming metals of Group IVB, comprising titanium, zirconium and hafnium and Group VB, comprising vanadium and columbium produced by: a. subjecting the metal to a hydrogen atmosphere to produce a friable mass, b. milling the hydride mass to produce a hydride powder having an average Fisher sub-sieve particle size less than 10 microns, c. heating the hydride powder in a chemically non-reactive environment to remove the hydrogen, d. further heating the degassed powder in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a porous sintered cake in which at least the finer powder particles are bonded, e. milling the porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), f. heating the aggregates in a chemically non-reactive environment to a sufficient temperature and for a sufficient time to produce a re-agglomerated porous cake, g. milling the re-agglomeration porous cake into aggregates each comprised of multiple initial particles, said aggregates typically having a particle size substantially larger than the initial particles of step (b), h. screening the milled, re-agglomerated powder through about a 250 mesh screen to obtain the +250 mesh aggregates and to remove -250 mesh particles or aggregates, i. heating the -250 mesh material in a chemically non-reactive environment to sufficient temperature and for a sufficient time to produce a porous sintered cake in which the powder particles are bonded, j. milling and screening the re-agglomerated material from step (i) into aggregates each comprised of multiple initial particles, said aggreates having a particle size substantially larger than the initial particles of step (b), and k. blending the milled and screened powder from step (j) with the +250 mesh powder from step (h) to produce the final powder.