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Diffusion Welding, DFW

Joining process by heat and pressure where the contact surfaces are joined by diffusion of atoms.

Illustration of Diffusion Welding, DFW

The process

Two workpieces [1] at different concentrations are placed between two presses [2]. The presses are unique for each combination of the workpieces, with the result that a new design is required if product design changes.

The heat equivalent to about 50-70% of the materials melting point is then supplied to the system, increasing the mobility of the atoms of the two materials.

The presses are then pressed together, causing the atoms to start diffusing between the materials at the contact area [3]. The diffusion takes place due to the workpieces being of different concentrations, while the heat and pressure only make the process easier. The pressure is therefore used to get the materials contacting surfaces as close as possible so that atoms can more easily diffuse. When the desired proportion of atoms are diffused, the heat and pressure are removed and the bonding processing is completed.