ebbinghaus1113Hydrogen embrittlement is an omnipresent issue when it comes to protecting against corrosion by coating the surface of metals. This applies above all to safety-relevant components that are subject to particularly high strength requirements. Ebbinghaus Verbund uses zinc thermo diffusion (ZTD) for the corrosion protection of bulk material and thus eliminates this problem.

The risk of hydrogen embrittlement occurs especially in pickling and coating processes in the galvanic surface coating. These processes cause changes in the ductility of the material due to the penetration and incorporation of hydrogen into the metal structure. These deposits can lead to so-called stress corrosion cracking. The hydrogen embedded in the metal structure impedes the sliding mechanisms of the workpiece, reduces the deformability and increases the residual stresses of the material. This can lead to component failure. The dry-running ZTD process does not lead to hydrogen embrittlement of the components, which makes the process particularly suitable for safety-relevant components.

Another argument reinforces the use of zinc thermo-diffusion in safety-related components. Due to the surface coating with conventional methods, depending on the layer thickness, the defined tightening torques can be changed by the applied protective layer. In addition, the threads of these coated screws or bolts often have to be reworked to ensure the required tolerances. Due to the mechanical reworking, the applied protective layer is partially destroyed again and the corrosion protection is impaired.

Since zinc-thermo-diffusion does not apply an additional layer, but the corrosion protection is incorporated into the edge area of ​​the material, mechanical post-processing is eliminated and the defined tightening torques do not change. In addition, the ZTD layer is mechanically much more stable than the protective layers of other methods and it does not age.