Tantalum powders' four applications

Three different types of tantalum powder

Tantalum powder is a dark grey, combustible metal powder. There are three primary types, each has a distinct physical shape and is derived from a unique process.

Nodular tantalum powder is made by molten sodium reduction of tantalum salt or solid magnesium reduction of tantalum (V) oxide. The powder is aggregates consisting of primarily particles and pores. It has relatively low density and high surface area.

Angular tantalum powder is made by hydride and crush of a solid ingot (either electron beam or vacuum arc melted), and de-hydride. The particle looks angular and is non-aggregated; the bulk density is typically higher than that of nodular.

Spherical tantalum powder is made by plasma inert gas atomization of any powder mentioned above. The particle has a near spherical shape with a relatively smooth surface, and narrow particle size distribution; all of which are critical factors for excellent flow and dense packing.

Tantalum powders are used in:

Tantalum capacitors

The powder is pressed into a porous pellet, sintered to improve particle bonding, electrolytically anodized to form a pentoxide (V) dielectric layer, coated with a cathode electrolyte, and encaged. This is the largest use of tantalum.

Tantalum mill products

The powder is pressed to a bar and sintered at high temperature to achieve a density as close to the true density as possible. The sintered bar is then processed into wires, rods, sheets, strips, and tubes, etc. Mill products made the sintered bars have finer grain structure, better drawability, and can sustain higher temperatures than those derived from melted bars or ingots.

New generation of tantalum sputtering target

The target is produced by pressing the powder in pure form or mixed with other metal powders, sintering it to near true density and shaped to a desirable geometry. The target has a uniform, fine grain structure, and has better quality than that made from traditional electron beam melted ingot. High temperature or corrosive resistant coating on another metal.

3-D printing

This is a new technology which builds the finished part one layer at a time. The process requires a powder with well-defined particle and size distribution to eliminate void in the printing process. Spherical powder is particularly important for this application.