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Diffusion Bonding
Two metallic components with engraved markings produced by precision diffusion bonding technology.

Advanced Joining for High-Performance Components

Diffusion bonding is a solid-state joining technology, which achieves high-quality joints without any local stresses or additional interlayer. It can join materials such as stainless steels, tool steels, aluminum, nickel-based superalloys, ceramics, glass, and copper. In addition, diffusion bonding is suitable for joining dissimilar combinations like steel and copper, titanium and ceramics, or titanium and steel. 

 

The process is also particularly well-suited for sensitive materials, including titanium, niobium, and zirconium, as it allows for a reliable bond without compromising material properties.

 

Find out more about the technology

Micro heat exchanger with fine structured surface pattern for advanced thermal management applications.

Application

The most important of the established applications are tempered injection molds (keyword: “conformal cooling”), hot runner manifold plates, cooling plates, and high-performance heat exchangers. With the help of large surfaces and minute duct structures, components can be realized with very high heat transfer rates and therefore with outstanding efficiency.

Two engineers standing beside a large blue industrial diffusion bonding system in a manufacturing facility.

Advantages

  • No external materials used during the joining operation

  • No liquid phase throughout the joining operation

  • High-vacuum atmosphere: smooth surface and the possibility of joining sensitive materials (Ti, Nb, Zr)

  • Very high strengths (close to those of the base materials)

  • Very high corrosion-resistance

  • Pore-free, visually imperceptible joint

  • Similar material joints: stainless steels, tool steels (1.2083, M333, etc.) titanium, aluminum, nickel superalloys, ceramic, glass, copper, and many others.

  • Dissimilar materials can be joined: steel/copper, titanium/ceramic, and titanium/steel

  • Large-scale bonds with no distortion

Interior view of a high vacuum furnace chamber with heating elements and substrate loading fixtures.

Service

PVA can now look back on a broad range of successfully joined material pairings. In cooperation with research facilities, we continue to develop our expertise in this innovative field of joining technology.

At our Wettenberg location, we operate two of the largest diffusion bonding systems available for services in Europe.

Each system features a uniaxial hydraulic pressing unit equipped with press plates made of high-strength graphite material. A multi-die system ensures that the pressing force is uniformly distributed over the press plate. The useful volumes available are 900 x 1,000 x 450 mm³ (WxLxH) and 840 x 840 x 600 mm³ (WxLxH).

Chamber evacuation to a high-vacuum level to purify the process environment

Procedure

The pressure welding process involves the simultaneous application of pressing forces and high temperatures. The components to be joined are heated to the required temperature under high-vacuum. The pressing forces are then applied by the ram (uniaxially). This helps smooth the rough peaks of the material surfaces thus establishing close material contact between the mating surfaces. In contrast to many other welding processes, diffusion bonding does without a liquid phase and external materials.

FAQ

Is it possible to bond multiple components in a single furnace cycle?

The furnace cycle is the primary driver of costs in diffusion bonding. By combining multiple components (of the same height and the same material), this process can become extremely efficient.

What requirements must the component fulfill?

In diffusion bonding, the surface of the join is a key criterion for ensuring a secure material joint. The general rule is that the lower the surface roughness and waviness of the component, the better the joining result. Macroscopic damage such as scratches or cracks should always be avoided to ensure the highest levels of impermeability and strength.

Can the service also be used for development projects?

This system is also available for individual development projects. Furthermore, our engineers can offer assistance in creating designs that are suitable for diffusion bonding.

Is series production also possible?

The diffusion bonding system is also available for series production. A corresponding annual batch size has a positive impact on pricing.

I'm not sure if this joining technology is suitabel for my component. Who can I contact?
  • For general questions about diffusion bonding, and specific questions concerning the technical design of components for diffusion bonding, please contact us via the contact form.
Which material combinations are possible?

Successfully joined similar material pairings:

  • Austenitic steels (1.4301, 1.4404, etc.)
  • Tool steels (1.2344, 1.2343, 1.2083, Böhler M333, etc.)
  • High-alloy aluminum materials (e.g. AW 6061)
  • Copper (oxygen-free)
  • Titanium, and many more.

Successfully joined dissimilar material pairings:

  • Tungsten to copper
  • Titanium to copper
  • Steel (e.g. 1.2767) to copper and many more.
How much material allowance should be included?

Since buckling of the material occurs due to the process, an allowance of 1 % to 5 % should be included.

How long does a diffusion bonding process take?

A furnace cycle lasts around 24 hours—including heating up and cooling down.

What is brazing supported by pressing force?

Large-scale joints cannot be brazed without distortion. Material distortion during vacuum brazing is problematic insofar as it can lead to brittleness and therefore a loss of strength due to the enlargement of the brazing joint. The application of sufficient pressing forces in the hot press can prevent this distortion. The result is securely brazed material joints.

Interested in our diffusion bonding service?

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