초록 ▼

A process for sizing (i.e., comminuting) a tantalum powder including agglomerates of smaller particles, which process yields a tantalum powder having an as-comminuted agglomerate size distribution with the product of the Volume Mean Diameter, MV (in microns as measured by light scattering techniques

A process for sizing (i.e., comminuting) a tantalum powder including agglomerates of smaller particles, which process yields a tantalum powder having an as-comminuted agglomerate size distribution with the product of the Volume Mean Diameter, MV (in microns as measured by light scattering techniques such as Microtrac analysis), times specific surface area, BET (m.sup.2 /g), being less than about 25. These powders after sizing typically have ratios of Scott Bulk Density : BET Surface Area in the range from about 20 to about 35. Also provided are powders having a substantially unimodal and narrow agglomerate size distribution in all stages of production, namely after sizing (i.e., deagglomeration by comminution), thermal agglomeration (i.e., heat treatment), and deoxidation. These resultant powders have high surface area and good flowability properties and, upon sintering, exhibit controlled shrinkage with high porosity. Further provided are sized heat treated tantalum powders having agglomerate particle sizes wherein the product of the Volume Mean Diameter, MV, times the specific surface area, BET, is in the range from about 90 to about 250. Sized and agglomerated powders which are deoxidized are also provided wherein the product of the Volume Mean Diameter, MV, times the specific surface area, BET, is in the range from about 90 to about 250.

대표청구항 ▼

[ What is claimed:] [1.] A process for preparing a tantalum powder wherein a basic lot powder of tantalum is prepared by a reduction step followed by water wash, acid leach, and drying steps prior to heat treating, said basic lot powder of tantalum having basic lot agglomerates comprised of individu

[ What is claimed:] [1.] A process for preparing a tantalum powder wherein a basic lot powder of tantalum is prepared by a reduction step followed by water wash, acid leach, and drying steps prior to heat treating, said basic lot powder of tantalum having basic lot agglomerates comprised of individual powder particles, the improvement comprising:subjecting said basic lot powder to a deagglomeration step between said reduction and heat treat steps, said deagglomeration step being continued until the deagglomerated product has a size distribution such that the product of Volume Mean Diameter, MV in microns, times specific surface area, BET in m.sup.2 /g, is below about 25.