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Performance Metal Bellows and Expansion Joints


Metal bellows and expansion joints are produced by welding, hydroforming, and electroforming, but only electroformed bellows are seamless and isotropic. Their strength is not compromised by the heat of welding, or the strains of cold working. Thin and thick wall, multi-ply and multi-lamina bellows can be easily and cost-effectively electroformed, complete with integrated flanges and end plates.

Bellows are electroformed by 
electroplating metal onto a machined aluminum mandrel (model) of the desired configuration. After electroforming, aluminum is chemically dissolved, leaving behind a stress-free bellows, as shown in the illustration on the right.

NiCoForm electroforms bellows with NiColoy®, an alloy that outperforms nickel in every respect. Competition's nickel bellows have a lower mechanical strength, and a narrower (up to 350°F/175 °C) operating range. Therefore, nickel bellows can not be reliably welded or brazed. Due to electroformed nickel's porosity, for leak tightness conventional nickel bellows rely on a copper lamina, sandwiched between two nickel layers.

NiCoForm's proprietary  NiColoy® is free from the limitations of electrodeposited nickel. With superior mechanical and thermal properties, this alloy can be used over a wider temperature range (cryogenic up to  660 ºF/ 350 °C), and withstand higher stresses and strains without permanent deformation. NiColoy® bellows can be welded, brazed, electrojoined and soldered. Their stress-free nature assures longer cycle life in extension, compression, bending and rotation. Non-porous and corrosion resistant, NiColoy® bellows are helium leakproof with no copper lamina.

NiColoy® bellows outperform nickel ones, and are the only choice when extended cycle life and greater consistency are essential.

  • NiCoForm's mass-electroforming technology produces bellows with excellent part-to-part consistency and reliable performance in extension, compression, torque, bending, and rotation
  • NiColoy® bellows can be produced with walls as thin as 0.0002” (5 µm), and diameters as low as 0.02” (0.5 mm) - much smaller than possible with alternate methods - making them ideal for precision sensing applications. Electroformed bellows can also be as large as 12” (300 mm) in diameter and 25” (625 mm) long
  • When appropriate, copper, silver, gold, rhodium, and other coatings or laminas are used to enhance the bellows' corrosion resistance, mechanical, thermal and electrical properties
  • Leak testing of bellows is performed by helium mass spectrometry up to 10-12 ccHe/sec
  • NiColoy® bellows can be permanently joined to mating components by electrojoining, soldering, welding, brazing, and with adhesives
In addition to NiColoy®, for special applications requiring low spring rates, corrosion resistance in marine environments, high pressure rating, etc., copper, or multi-ply NiColoy® and copper bellows are produced.
Partial list of Electroformed Bellows Applications

Accumulators Actuators Compensators Couplings




Flexible Shaft
Low Inertia

Expansion Joints Seals Sensors Miscellaneous



High Sensitivity

Sealed Contacts
Dynamic Pump Housings

Whether you are supporting an existing product or develop a new application, our expertise can help you quickly and efficiently design, prototype and manufacture your bellows.

Please enter your project parameters into the form here, so we can assist with your bellows design.

Choose from an ever-expanding standard line of components, or let us custom engineer bellows to your specifications - the choice is yours



Bellows electroforming sequence
Bellows Electroforming Steps (X-section), left to right: machined mandrel, NiColoy-plated mandrel, NiColoy bellows after mandrel removal

Electroformed 3" OD bellows with integrated flanges (NiCoForm proprietary technology)

Metal Bellows
Small Electroformed Bellows

Bellows assembly
NiColoy® Bellows with Hubs, Integrated by Electrojoining

  NiCoForm, Inc. 72 Cascade Dr. Rochester, NY 14614 ITAR Registered
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