Tantalum

Atomic number 73
Atomic weight 180.947
Melting temperature °C 2996
Boiling temperature °C 5425 +/-100
Density g/cm3 16.654 at 20 °C

Tantalum is a hard and ductile shiny grey metal. The name derives from the mythological Tantalus and refers to the characteristic of tantalum oxide Ta2O5 of not forming salt in contact with acids. Extraction takes place mainly from copper or tin ores containing tantalum and slags (tantalite or coltan). Economically important deposits are currently in Australia, Brazil, Canada and Thailand. A large part of tantalum production is used for electronic capacitors. In addition to its application as an alloying agent in the steel sector, or as tantalum carbide in hard metals, tantalum is available in many different branches.

The discovery of tantalum is due to the Swedish chemist Anders Gustaf Ekeberg in 1802. The metal was identified by analysing Finnish tantalite and yttrotantalite from Ytterby. In 1809 Wollaston analysed both tantalite and columbite (niobium), concluding that the two elements were identical. The difference was discovered only in 1846 by Heinrich Rose, who gave the second element the name Niobium, while in the United States it was still long called Columbium. In 1903 Werner von Bolton succeeded in stably refining the metal.

 

Ramisa Sas handles semi-finished products in Tantalum and its main alloys.

1. Wire in coil, wire on spools
2. Round bars, square bars, small bars, cylinders
3. Flat bars, foils, strips, sheets, plates and platelets
4. Round tubes, square tubes, tubes to drawing, seamless tubes, welded tubes, fittings
5. Electrodes, welding wire
6. Fasteners, screws, bolts, nuts, discs
7. Metal meshes and nets, custom parts and components (turned or CAD-machined), forged parts
8. Tantalum bars
9. Tantalum foils
10. Tantalum plate 99.9% 1.2 x 50 x 50 mm
11. Tantalum flat bars 99.95% 1 x 6 x 12 mm
12. Tantalum rods 99.95% 3 x 40 mm
13. Tantalum rings Ta 99.95% wire diam. 1.5 mm to drawing
14. Tantalum screws 99.95% DIN 84 M4 x 12 mm
15. Tantalum wire
16. Tantalum flat bars
17. Forged tantalum parts
18. Welded tantalum wire
19. Tantalum strips
20. Tantalum sheets
21. Tantalum tubes
22. Cut tantalum tubes
23. Tantalum fittings
24. Tantalum meshes
25. Tantalum discs
26. Tantalum discs 99.95%, 200x1 mm
27. Tantalum discs 99.9% diam. 34 x 2.3 mm
28. Standard tantalum components (screws, nuts, ...)
29. Tantalum crucibles
30. High-temperature tantalum components
31. Custom tantalum components to customer drawing
32. Tantalum for the gold and jewellery industry
33. Tantalum rings
34. Tantalum powder 99.2%, size less than 100 µm

Consultancy and design. Ramisa can offer consultancy and design for finished parts and machining in tantalum.

 

Important characteristics and applications

1. excellent resistance to acids and to many liquid metals
2. very high melting point, exceeded only by tungsten and rhenium
3. very ductile, weldable and with relatively good machinability
4. very good biocompatibility

Tantalum is used as pure metal or alloyed in chemical plants for containers, agitators, tubes and heat exchangers, in medical technology for implantology and surgical instruments, as well as in high-temperature equipment for heat conductors, in thermal protection plates and other components.

Tantalum-tungsten (TaW 2.5)

This alloy, compared with titanium, has greater strength, especially higher thermal resistance.

Tantalum-tungsten (TaW10)

TaW10, compared with pure tantalum and TaW2.5, has considerably higher strength at very high temperatures. Due to the difficult handling and processing, many semi-finished products have limited availability.

Main alloys

1. Ta 99.95% (R05200 vacuum melted)
2. Ta 99.95% (R05400 powder)
3. Ta 99.99% (4N quality)
4. Ta97.5W2.5 (R05252 vacuum melted)
5. TaW (tantalum-tungsten alloy)
6. Ta90W10 (R05255 vacuum melted)
7. TaNb (tantalum-niobium alloy)
8. Ta60Nb40 (R05240 vacuum melted)

ASTM standards

ASTM B364 (Ta and Ta alloys - ingots, raw ingots)

ASTM B365 (Ta and Ta alloys - bars, wires)

ASTM B708 (Ta and Ta alloys - plates, sheets, strips)

ASTM B521 (Ta and Ta alloys - tubes, welded and seamless)

ASTM F560 (pure tantalum - medical applications)

Welding on tantalum

Basically, all welds on tantalum are carried out under vacuum and in a protective atmosphere to prevent the material from becoming brittle. Only tantalum is used as a welding element in order to keep the anti-corrosive characteristics of the material constant and uniform. Normally, a standard dye-penetrant test (Dye-Test / LP) is carried out on all welds.