A Guide to Choosing Pure Tantalum & Tantalum Alloys.

Commercially Pure Tantalum & Tantalum Alloys Ta2.5%W, Ta7.5%W & Ta10%W have similar properties but are different. Choose the version best suited to your application.

When deciding between Commercially Pure Tantalum and Tantalum Alloys (Ta2.5%W, Ta7.5%W, Ta10%W), your choice should be guided by the application requirements — especially factors like strength, corrosion resistance, fabricability, cost, and operating environment.

Here’s a breakdown of how to choose the right one:

1. Commercially Pure Tantalum (CP Ta)

Purity: Typically ≥99.9% Ta
Properties:
- Excellent corrosion resistance (especially to acids like HCl, H₂SO₄, HNO₃)
- Good ductility and formability
- Lower strength than alloys
- Excellent biocompatibility (often used in medical implants)
Best For:
- Chemical processing with extremely corrosive environments (unless higher strength is needed)
- Electronics, capacitors
- Medical implants where biocompatibility is key

Choose CP Ta if corrosion resistance and purity are more important than mechanical strength.

2. Tantalum-Tungsten Alloys (TaW Alloys)

These are tantalum strengthened with tungsten, increasing strength while maintaining good corrosion resistance.

General Properties of Alloys:

Alloy	Tungsten Content	Strength	Ductility	Corrosion Resistance	Use Cases
Ta2.5W	2.5% W	Slightly stronger than CP	Good	Excellent (slightly lower than CP)	Heat exchangers, chemical equipment
Ta7.5W	7.5% W	Higher strength	Lower ductility than CP	Excellent	Nuclear, aerospace, medical
Ta10W	10% W	Highest strength of group	More difficult to fabricate	Still very good	High-stress environments, high-temp or high-pressure systems

Choosing Guide:

Application Need	Recommended Material
Maximum corrosion resistance + ductility	CP Tantalum
Moderate strength + corrosion resistance	Ta2.5%W
Higher strength + good corrosion resistance	Ta7.5%W
Maximum strength + harsh environments	Ta10%W

Other Factors to Consider:

Formability/Fabrication: CP Ta and Ta2.5W are easier to weld and form than Ta7.5W or Ta10W.
Cost: Cost increases with tungsten content.
Availability: CP Ta and Ta2.5W are more commonly stocked.
Weldability: CP Ta and Ta2.5W weld well; higher tungsten content alloys may need pre/post-weld heat treatment.
High Temperature Stability: All Ta-W alloys perform better than CP Ta at elevated temperatures.

Final Recommendation:

For general chemical applications: Start with Ta2.5W — balance of strength and corrosion resistance.
For structural or high-pressure systems: Use Ta7.5W or Ta10W depending on mechanical load.
For highly formable, ultra-pure needs: Stick with Commercially Pure Tantalum.

Based on your specific application, operating temperature, pressure, or corrosive media, the knowledgeable sales engineers at Rembar can help you pick the right version for your application.

REFERENCE : ASTM Specifications for Tantalum;

ASTM F560 – R05200, unalloyed tantalum

ASTM B365-12;

1.2.1 R05200, unalloyed tantalum, electron-beam furnace or vacuum-arc melt, or both,

1.2.2 R05400, unalloyed tantalum, powder-metallurgy consolidation,

1.2.3 R05255, tantalum alloy, 90 % tantalum, 10 % tungsten, electron-beam furnace or vacuum-arc melt, or both,

1.2.4 R05252, tantalum alloy, 97.5 % tantalum, 2.5 % tungsten, electron-beam furnace or vacuum-arc melt, or both, and

1.2.5 R05240 tantalum alloy, 60 % tantalum, 40 % niobium, electron-beam furnace or vacuum-arc melt, or both.

ASTM B708-12(2019); Standard Specification for Tantalum and Tantalum Alloy Plate, Sheet, and Strip