Vacuum Arc-Cast (VAC) Tungsten is an ultra-high-purity tungsten grade produced by fully melting tungsten under vacuum arc conditions, rather than relying solely on powder metallurgy. With purity exceeding 99.97%, VAC tungsten offers superior chemical cleanliness, isotropic microstructure, and near-theoretical density.
Unlike sintered tungsten, vacuum arc-cast tungsten is completely molten and re-solidified, eliminating micro-porosity and minimizing interstitial contaminants such as oxygen, nitrogen, hydrogen, and carbon.
Strengthening & Metallurgical Behavior
Grain Structure
• Large columnar or equiaxed grains (cooling-rate dependent)
• Isotropic mechanical behavior (no PM texture)
Strengthening Mechanisms
✔ Grain boundary strengthening
✔ Reduced interstitial embrittlement
✔ High lattice integrity from full melting
❌ No dopants or alloying — purity itself is the strengthening factor
Refining & Processing Properties
Manufacturing Route
• High-purity tungsten feedstock
• Vacuum Arc Melting (VAM) or Vacuum Arc Remelting (VAR)
• Controlled solidification under ultra-high vacuum
• Optional hot forging or rolling
• Precision machining and grinding
Why Vacuum Arc Casting Matters
• Eliminates sintering porosity
• Degasses O, N, H, and C
• Breaks PM grain-boundary weakness
• Produces true bulk tungsten
Available Forms
✔ Vacuum arc-cast ingots
✔ Rods & bars
✔ Plates & blocks
✔ Discs & sputtering targets
✔ High-precision machined parts
✔ Single-piece structural components
Key Characteristics
✔ Ultra-high chemical purity
✔ Near-theoretical density
✔ Excellent high-temperature creep resistance
✔ Improved ductility vs PM tungsten
✔ Exceptional thermal shock resistance
✔ Ultra-low outgassing (UHV compatible)
✔ Fully isotropic properties
Limitations
⚠ Higher cost
⚠ Limited global suppliers
⚠ Difficult to produce ultra-thin foils
Typical Applications
Aerospace & Space
Rocket nozzle inserts, thermal shields, hypersonic components
Nuclear & Fusion
Plasma-facing components, divertors, first-wall structures
Semiconductor & Vacuum
Ion implantation parts, UHV chambers, sputtering targets
Defense
High-density inert penetrators, advanced kinetic systems
Scientific & Research
Extreme-temperature fixtures, experimental test hardware
Comparison: VAC Tungsten vs PM Tungsten
| Property | VAC Tungsten | PM-Sintered Tungsten |
|---|---|---|
| Purity | > 99.97% | ~99.95% |
| Density | Near theoretical | Slightly lower |
| Porosity | None | Trace |
| DBTT | Lower | Higher |
| UHV Suitability | Excellent | Moderate |
| Cost | High | Lower |
Why Choose Vacuum Arc-Cast Tungsten?
Choose VAC Tungsten (>99.97%) when extreme thermal exposure, plasma interaction, ultra-high vacuum compatibility, and absolute structural integrity are mandatory — and failure is not an option.