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Stainless Steel 40 Foil (Light Tight)
Available Configurations
Properties common to all products in this list
Health hazard/Hazardous to the ozone layer
Serious health hazard
Key Features
Stainless Steel 40 Foil (Light Tight) (UNS S21900), also known as Nitronic 40 or 21-6-9, is a nitrogen-strengthened austenitic stainless steel foil with approximately 21% chromium, 6% nickel, and 9% manganese, manufactured to a pinhole-free surface that ensures complete blockage of visible and near-visible light transmission:
Nitrogen Alloying Raises Yield Strength to Roughly Twice AISI 304
Nitrogen alloying — typically 0.15-0.40 wt% — serves as the primary strengthening mechanism, raising yield strength to approximately 380-415 MPa in the annealed condition, roughly twice that of AISI 304.
Retains Full Austenitic Ductility & Non-Magnetic Character
Despite its elevated strength, Nitronic 40 retains full austenitic ductility, non-magnetic character, and excellent toughness at cryogenic temperatures — a combination not available in conventional strengthened austenitic foils.
Superior Resistance to Pitting & Stress Corrosion Cracking
Nitrogen content confers superior resistance to pitting and stress corrosion cracking compared with standard 18-8 grades, while higher manganese content partially substitutes for nickel.
Complete Blockage of Visible & Near-Visible Light
Manufactured to a pinhole-free surface, this foil ensures complete blockage of visible and near-visible light transmission, combining optical isolation with elevated structural strength.
Excellent Toughness at Cryogenic Temperatures
Excellent toughness at cryogenic temperatures supports use of this foil in cryogenic optical systems and quantum optics applications requiring reliable performance at extremely low temperatures.
Industrial Applications
Stainless Steel 40 Foil (Light Tight) is used across aerospace, cryogenic optics, and quantum optics sectors where optical isolation must coexist with higher structural strength than standard austenitic light-tight foils provide:
- ✦ Cryogenic Optical Systems
- Used in cryogenic optical systems, where excellent toughness at cryogenic temperatures combined with complete light exclusion ensures reliable optical isolation under extreme low-temperature conditions.
- ✦ Precision Photonic Instruments
- Formed into precision photonic instruments, where yield strength roughly twice that of AISI 304 provides structural reliability beyond standard austenitic light-tight foils.
- ✦ Vacuum Chamber Enclosures
- Used in vacuum chamber enclosures, where superior resistance to pitting and stress corrosion cracking compared with standard 18-8 grades ensures long-term reliability in demanding vacuum environments.
- ✦ Aerospace Applications
- Applied in aerospace systems where optical isolation must coexist with higher structural strength than standard austenitic light-tight foils provide.
- ✦ Quantum Optics, Cryogenic Instrumentation & Semiconductor Testing Research
- Supports work in quantum optics, cryogenic instrumentation, and semiconductor testing where both light exclusion and elevated structural strength in the barrier material are experimental requirements.
Tolerances
| Thickness | <0.01mm | ±25% |
|---|---|---|
| Thickness | 0.01mm - 0.05mm | ±15% |
| Thickness | >0.05mm | ±10% |
| Linear dimension | <100mm | ±1mm |
| Linear dimension | >=100mm | +2 / -1% |