Influence of electron beam liquid phase surface treatments on the corrosion resistance of AZ91D using different additive deposition techniques

•Electron-beam alloying and cladding were applied successfully on the Mg alloy AZ91D.•The AlSix additive deposition technique influences alloyed-layer quality strongly.•Low oxygen contents in the deposition layers result in homogeneous alloyed layers.•The hardness of defect-free layers is increased up to three times compared to AZ91D.•The corrosion behaviour is improved greatly compared to the untreated base material.

Electron beam alloying (EBA) and electron beam cladding (EBC) were applied on AZ91D using Al-based additives. For EBA, additives were pre-deposited by atmospheric plasma spraying (APS) and cold gas spraying (CGS). In the case of EBC, a wire was used for in situ additive deposition. Polarisation test were carried out to investigate the corrosion behaviour of layers with Mg-rich (EBA) and Al-rich (EBC) layer matrices depending on the element contents of Mg, Al, and Si. In 0.001 M NaCl solution, the corrosion potential is significantly improved compared with the untreated AZ91D and corrosion current densities of the AlSi12 reference material are approached.