Diffusion bonding for high performance plate heat exchangers

Let’s talk again about heat exchangers, but more specifically about Diffusion Bonding, a special construction process of exchangers related to plate heat exchangers.

We all know that several kinds of plate heat exchangers exist: inspectable exchangers, brazed plate exchangers, fully welded plate heat exchangers and, furthermore, there is a kind of full inox plate heat exchangers which are made using this special processing technology called diffusion bonding.

In fact, this is an innovative welding process that allows to join two similar or different metals through a sort of permeation of the metals’ crystalline structure. And at much lower temperatures of those required for the melting process of the metals.

How is it possible? I’m not going too much in depth with details, which can be found online. Essentially, the exchangers are placed inside special furnaces, under vacuum conditions, where they reach temperatures equal to 65, 70 or 75% than the melting temperature and under pressure the permeation of the crystalline structure is achieved. Therefore, the process generates extremely resistant welding joints without material addiction and with no additional weight.

This special construction process has many applications in a variety of sectors including main sectors such as aerospace, oil and gas and also the hydrogen industry which is actually a really emerging trend sector.

These exchangers offer a lot of advantages and some disadvantage. Among the disadvantages is the construction process that increases costs, because it employs special furnaces and a very peculiar processing that requires long cycle times and thus higher costs.

On the side of advantages, the fact that these are exchangers made in a unique material and fully welded and so they offer a very high resistance to extremely high pressures and temperature levels. This technology can be applied both to stainless steel exchangers and in titanium, but also to different materials, where the technology becomes a little more complicated.