The Diffusion Bonding process is the particular solid state welding me-thodology with which the heat transfer plate pack of the PCHE exchangers is realized. The process takes place in ovens at very high pressure and tem-perature, obtaining atomic-level welding of the material at all contact points of the plates. The joining of the plates therefore takes place without using brazing, external welding or gaskets. The methodology obtains a mo-nolithic block of the plate pack in which, after a first stage of deformation under hypostatic pressure and the creation of a joint interface, in fact the joint disappears thanks to the migration of particles between the two wel-ded surfaces, creating a very strong bond and pore-clearing. The result is a final microstructure without visible joints between the plates, in a mono-bloc structure with very high structural integrity and robustness, without the use of filler materials.
