A homogenisation pre-treatment for adherent and corrosion-resistant Ni electroplated coatings on Mg-alloy AZ91D

• A homogenisation pre-treatment for electroplating Ni on AZ91D was studied.
• The pretreatment effectively removed surface β-phase and promoted a surface suited to coating interlocking and deposition.
• Adherent and corrosion-resistant Ni coating on AZ91D was achieved by electroplating.
• The homogenisation pre-treatment can be extended to other coating technologies.

Multi-step Ni electroplatings were applied to AZ91D following the development of a homogenisation pre-treatment. The Ni coating was well adhered, as verified by thermal shock testing, and provided corrosion protection in 3.5 wt.% NaCl for 74 h at a coating thickness of ∼15 μm. Being a cathodic coating, further protection in the presence of defects was not demonstrated herein, however realisation of quality Ni coatings on Mg is technologically important. To this end, achieving microstructural homogeneity on AZ91D is critical prior to plating or coating (such as electroless plating and chemical conversion coating) multi phase Mg-alloys.