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You did everything right—modeled, simulated, and stress-tested like a pro.
But then, under heat, your perfectly engineered part shifted. Just enough to throw everything off. Could it be UNS K94800 that provides a solution for such issues?

Why?
Because most materials expand. Quietly. Relentlessly.
And when you’re working at micron-level tolerances, that’s all it takes.

Introducing DOMADIA™ Dilaton 51Cr1, a FeNi51Cr1 alloy based on UNS K94800, also known as Alloy 48 or Nilo 48.

Enhanced with just the right touch of chromium, it doesn’t buckle, bend, or misbehave under thermal stress.
It stays exactly where you left it—even when things heat up.

What is DOMADIA™ Dilaton 51Cr1 (UNS K94800 / Alloy 48 / Nilo 48)?

DOMADIA™ Dilaton 51Cr1 is a specialized iron-nickel alloy (FeNi51Cr1) engineered for ultra-low thermal expansion and exceptional dimensional stability. It is based on the UNS K94800 designation, which is commonly referred to as Alloy 48 or Nilo 48.

This material is part of the controlled expansion alloy family, specifically designed to maintain tight dimensional tolerances even when exposed to changing temperatures. What sets DOMADIA™ Dilaton 51Cr1 apart is its fine-tuned chemistry—containing approximately 51% nickel and 1% chromium, with iron making up the balance.

The addition of chromium enhances corrosion and oxidation resistance, making it ideal for vacuum environments, high-precision optics, semiconductor tooling, aerospace, and medical applications.

Chemical Composition

This precise balance ensures thermal stability along with surface integrity in harsh operating environments.

Mechanical & Physical Properties

Standards & Designation

• Material Name: FeNi51Cr1
• Standard: SEW 385 / DIN 17745
• UNS K94800
• DIN 2.448
• Brand Name: DOMADIA™ Dilaton 51Cr1

Other Designations

• ASTM A753 ALLOY 2
• ASTM F30
• MIL N-14411B Comp 3

Applications of DOMADIA™ Dilaton 51Cr1

1. Precision & Measurement Systems

• Optical Instruments (Microscopes, Telescopes, High-Res Cameras):
  Maintains alignment and imaging accuracy by resisting dimensional changes due to temperature variations.
• Laser Interferometry Bases:
  Prevents micro-shifts in laser optics setups, essential for metrology and lab-based precision measurement.
• X-ray and MRI Tables:
  Provides stable platforms in medical imaging where even slight expansion could distort image resolution.

2. Semiconductor & Electronics Manufacturing

• Semiconductor Manufacturing Fixtures:
  Ensures flatness and mechanical stability during thermal cycling in wafer processing and lithography tools.
• Electronic Sensor Mounts:
  Prevents drift in sensor calibration caused by thermal expansion or contraction.
• Microelectronic Components & Lead Frames:
  Forms reliable glass-to-metal seals in semiconductor packaging and delicate electrical components.
• Shadow Masks in CRTs:
  Preserves the precise geometry of the mask, ensuring long-term image clarity and color consistency.

3. Glass-to-Metal Sealing Applications

• The alloy’s closely matched thermal expansion coefficient with glass makes it ideal for hermetic seals in:
  • Incandescent lamps
  • Radio valves (vacuum tubes)
  • Semiconductor packages
  • Sensor enclosures
    This prevents cracking or stress at the glass interface, ensuring leak-proof, reliable seals even under thermal stress.

4. Thermostatic and Thermal Devices

• Industrial Thermostats (up to 450°C / 840°F):
  Used in bimetallic strips and thermal switches, where consistent expansion characteristics are vital for actuation and control.
• Bimetal Devices:
  Balances thermal expansion in composite strips used for thermal regulation, timing mechanisms, or temperature control.

5. Aerospace & Vacuum Applications

• Aerospace Control Components & Tooling:
  Maintains structural integrity during extreme thermal cycling in flight, satellite, or reentry conditions.
• Vacuum Systems & Enclosures:
  Performs reliably in vacuum environments, where outgassing and thermal mismatch can compromise seals and alignment.

Why DOMADIA™ Dilaton 51Cr1 Over Standard Invar 48?

While most engineers typically turn to Invar 48 (FeNi48) by default, there are situations where it may fall short. However, when higher corrosion resistance, slightly improved strength, and enhanced surface stability under oxidation are required, FeNi51Cr1 becomes the superior choice. In fact, the addition of chromium is not merely cosmetic—rather, it provides a crucial layer of durability without compromising the alloy’s hallmark property: low thermal expansion.

⚠️ Disclaimer:
“Invar” is a registered trademark of Imphy Alloys / Aperam. DOMADIA™ is not affiliated with or licensed by them. References to Invar are for comparison only. DOMADIA™ Dilaton 51Cr1 is an independently engineered FeNi51Cr1 alloy with comparable or improved performance in precision applications.

Available Forms

We manufacture and supply DOMADIA™ Dilaton 51Cr1 in various precision-processed shapes:

Each form is available in custom dimensions with tight tolerances for high-performance assemblies.

Conclusion

FeNi51Cr1 Alloy – DOMADIA™ Dilaton 51Cr1 isn’t just another low-expansion material. Rather, it’s a strategic choice for engineers who demand peace of mind, especially when tolerances are tight and temperature variations are inevitable. Thanks to its unique composition, it keeps your components stable—even when everything else is shifting.

Therefore, the next time you’re designing for precision, don’t settle for the ordinary. Instead, choose the silent hero of dimensional stability.
ChooseDOMADIA™ Dilaton 51Cr1—because consistency under pressure isn’t just preferred, it’s essential.

 Connect with DOMADIA Metals to bring the magnetic force of the future into your designs.

 Explore our full range of precision alloys and engineering materials at https://domadia.net/

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