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The scope of this specification is to define the characteristics of IF-1 grade beryllium foil that is made from ultrahigh purity input material. It defines the requirements for beryllium foil and x-ray windows produced by machining, extruding, slicing and/or hot rolling Beryllium ingots cast from vacuum melted electrolytically refined flake, designated IF-1.


Vacuum cast beryllium ingots of IF-1 specification contain a minimum beryllium content of 99.8% and conform to specified maximum chemical limits. 


Foil to this specification is available in the following forms:

  • Flat stock in standard thickness range 0.0001" (2.5 micrometers) to 0.020" (508 micrometers).
  • Cut to shapes such as rectangles, circular discs and other configurations.
  • Vacuum tight, optically dense or as-rolled in specified thickness ranges.


  • Foil Integrity: IF-1 Beryllium Foil is available in three classifications of integrity
  • Vacuum Tight: The foil will have no detectable leaks.  This will be tested with a helium mass spectrometer leak detector with a sensitivity of 1 x 10-9 atm-cc/sec. Thickness range: 0.0003 – 0.010 inches
  • Optically Dense: The foil will be impenetrable by light.  This will be tested by illuminating one side of the foil over a restricted area with a high intensity light source, and then viewing from the opposite side in a darkened room.Thickness range: 0.0002 – 0.010 inches
  • As-Rolled: The foil is supplied in as-produced condition, and is not inspected or guaranteed to be vacuum tight or optically dense.Thickness range: 0.0001 – 0.010 inches
  • Surface Quality: Material will be uniform in quality and condition, clean, sound, and free from foreign materials, and from internal and external imperfections that affect the fabrication or performance of parts.
  • Surface Finish: The surface finish of standard foils shall be 40 microinches Ra or better. Various thicknesses may be available in different surface finishes. Please consult Materion Electrofusion for availability.

Special tolerances on disc and straight-cut foils are available on request. Please consult Materion Electrofusion for price and availability   


Materials will be appropriately identified, packaged and labeled to comply with applicable government regulations and/or standard procedures of Materion Electrofusion .   


Handling beryllium in solid form poses no special health risk. Like many industrial materials, beryllium-containing materials may pose a health risk if recommended safe handling practices are not followed.

Inhalation of airborne beryllium may cause a serious lung disorder in susceptible individuals. The Occupational Safety and Health Administration (OSHA) have set mandatory limits on occupational respiratory exposures.

Read and follow the guidance in the Safety Data Sheet (SDS) before working with this material. For additional information on safe handling practices or technical data on beryllium, contact Materion Electrofusion.

Contact Materion Electrofusion

To learn more about IF-1 Beryllium/Ultrahigh Purity Foil Specifications, contact Materion Electrofusion.