Zapp's Invar 36® Foils

Invar is a registered trademark of Aperam Alloys Imphy

Zapp foils made of Invar 36® exhibit tightest thickness tolerances, world class cleanness and a superior surface finish. The material 1.3912, also known as Ni36 or Alloy 36, is an iron-nickel alloy with 36% nickel content.

[Translate to Englisch (UK):] Stahlband


  • Standard thicknesses: 0,025 - 0,050 mm
  • Standard width: up to 400 mm

Physical Properties

Thermal expansion coefficient between 20 and 100°C:
0.8 x 10-6/K ≤a ≤1.6 x 10-6/K

Delivery Forms / Finish

  • Coils with slit edges – cold rolled
  • Coils with slit edges – cold rolled and tension annealed

The tension annealed material is recommended for etching or photochemical machining processes and for operations at elevated temperatures, where dimensional stability is essential for the production of patterns or components.

Chemical Analysis (Weight %)



Electronic Devices

Zapp precision foils of Zapp SuperClean Invar 36 are used for various applications in the electronic industry.

  • Fine metal masks (FMM) and open masks for OLED production
  • Bi-metals, as sealings between glass and metals
  • Stencil masks for the production of electric devices
  • Specialized conveyor belts

Zapp's Superclean Invar 36 foils

Patterning of masks

The patterning of masks is usually carried out by a photochemical etching process, during which material is removed to produce through apertures. In order to maintain the desired shape and tolerances after the etching process, internal stresses must be minimised. Furthermore, the low thermal expansion and its tight control allows the use of Zapp SuperClean Invar36 over a large temperature range, even in combination with other materials.

Shape accuracy

The shape accuracy of our superclean Ni36 precision foils is such that periodical patterns below 30 micrometre can be produced by photochemical machining. The combination of our know-how and modern equipment enables us to produce excellent flatness and tight tolerances.

Internal Cleanness

Zapp SuperClean Invar foils are essentially free from waves and at the same time internal stresses. For very precise micro-patterns our metallurgists have developed special metallurgical routes with our suppliers to meet the highest demands. In addition, to the standard metallurgical routes we have access to refined melting processes such as electro slag remelting (ESR) and vacuum arc remelting (VAR) with improved cleanness. For special applications we can offer our even cleaner Zapp SuperClean material for patterns down to a few microns. With respect to very small inclusions the material is significantly cleaner than remelted material. This is essential for the production of very small apertures.



Brochure Ni36 – Etching and Laser Cutting Applications



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