NILO® Alloy K – properties, applications and technical data
NILO Alloy K is a nickel-iron-cobalt alloy developed for applications where the thermal expansion coefficient of the material must match that of borosilicate glass and alumina ceramics.
The alloy is primarily used for glass-to-metal seals in applications where dimensional stability, repeatability and high reliability are crucial.
The controlled chemical composition makes NILO Alloy K particularly suitable for mass production of hermetic seals and other components where precise thermal properties are required.
Properties of NILO Alloy K
NILO Alloy K is a nickel-iron-cobalt alloy with a thermal expansion that is carefully matched to certain types of glass and ceramic materials.
The magnetic properties of the material are influenced both by the composition and by the heat treatment that the alloy undergoes. Properties such as permeability, coercive force and hysteresis loss may vary depending on process conditions and temperature.
- Type: nickel-iron-cobalt alloy for glass-to-metal seals
- Alloy: Ni-Fe-Co
- Structure: controlled expansion alloy
- Designations: NILO Alloy K, Kovar, ASTM F15, UNS K94610, Werkstoff 1.3981, FeNi29Co17
- Typical composition: Ni ~29%, Co ~17%, Fe ~balance
Advantages
- Very well controlled thermal expansion
- Good match to borosilicate glass and alumina ceramic
- High repeatability in mass production applications
- Suitable for hermetic glass-to-metal seals
- Good magnetic properties that can be optimized via heat treatment
Limitations
- Not intended for high mechanical loads
- Magnetic properties are sensitive to heat treatment and temperature
- Mainly used where controlled expansion is more important than high strength
Common product forms for NILO Alloy K
- Strip and sheet
- Round bar
- Wire
- Precision-machined components
- Special dimensions according to drawing
Typical components made from NILO Alloy K
- Glass-to-metal seals
- Hermetic enclosures
- Electronic component housings
- Vacuum components
- Ceramic and glass-sealed precision parts
Thermal and magnetic properties
NILO Alloy K is developed to match the expansion behavior of borosilicate glass and alumina ceramics, making it suitable for reliable seals in technical applications.
The magnetic properties of the alloy are largely controlled by composition, heat treatment and temperature. Coercive force, residual induction and hysteresis loss are clearly affected by the operating conditions.
Environments where NILO Alloy K performs well
- Glass-to-metal seals
- Electronic components
- Vacuum equipment
- Applications with high demands on dimensional stability
Environments to avoid
- Applications where high structural strength is more important than controlled expansion
- Environments where simpler alloys provide sufficient sealing or function
Technical data (annealed state)
| Yield limit |
~240 MPa |
| Tensile strength |
~520 MPa |
| Elongation at break |
~30 % |
| Density |
~8.2 g/cm³ |
| Modulus of elasticity |
~138 GPa |
| Thermal conductivity |
~17 W/m·K |
| Thermal expansion coefficient |
~5.0 × 10⁻⁶ /K (20–300 °C, matched to borosilicate glass) |
| Recommended maximum temperature |
~450 °C depending on application |
| Weldability |
Good – TIG and resistance welding are often used |
With a global network of suppliers, we can offer NILO Alloy K in technical dimensions for demanding glass-metal and precision applications.
Contact us for price, availability and technical advice.
Supplier of NILO Alloy K with certified quality
HARALD PIHL is one of Europe's largest suppliers of special alloys and advanced materials with controlled thermal properties, including alloys such as NILO Alloy K.
With over 100 years of experience in the metal industry, we deliver materials with full traceability and certification according to EN 10204 3.1 / 3.2 as well as relevant ASTM and ISO standards.
Cutting, testing and quality assurance are carried out in-house to ensure the right tolerances and fast global delivery for technically demanding projects.
- Europe's largest stock of nickel and titanium alloys
- Special alloys from stock
- ASTM / ISO standards
- Top quality for safety-critical applications
- Fast global delivery
- Full material certification (EN 10204 3.1 / 3.2)
- Over 100 years in the metal industry
- Nickel and titanium experts
