Advanced corrosion protection of additive manufactured light metals by ceramic surface through CERANOD® plasma electrolytical oxidation process
Plasma Electrolytic Oxidation (PEO), is an advancing electrochemical process for surface treatment producing a ceramic surface on a light metal and its alloy such as Aluminum, Titanium and Magnesium. The process transforms the surface into extremely hard oxide nanocrystalline ceramic. The result is an enhanced corrosion resistant barrier with significantly improved wear protection . Due to the nature of this process, the ceramic layer grows outward and inward, forming strong chemical bonds with the substrate.
Nowadays, the sophisticated and lightweight structure produced by additive manufacturing (AM) technology enables the fabrication of 3D structures with a high degree of freedom. It widens the range of applications in many sectors such as aerospace, automotive and medical implantation. While research focused on improving the strength of metallic AM components is rapidly progressing , the corrosion and wear protection of AM components are hardly addressed . The aim of this study is to improve the corrosion and wear resistance of the Aluminum AM components and compare with PEO processed conventional Al casting alloy. For this reason, the properties of the CERANOD® - PEO coating on a printed AlSi10Mg alloy produced by the Selectively Melting process (SLM) have been investigated. The PEO surfaces were produced using different parameters, and the microstructure and morphology of the resulting coatings were characterized by SEM/EDS. The corrosion performance of the PEO coating was analyzed using electrochemical impedance spectroscopy (EIS).
The results exhibit high corrosion protection of the Al AM components, whereas still the material’s pores, which are typical for the AM process, show an enclosed homogenous PEO surface, and, thus, a further increasing of the corrosion protection