Magnesium fabricated using additive technology: Specificity of corrosion and protection

Direct laser deposition (DLD) technology was used to obtain magnesium (Mg) samples in this work. The morphology, composition, electrochemical and mechanical properties of the Mg specimens with and without protective layers were investigated using microhardness and scratch tests, SEM-EDX and XRD analysis, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and immersion tests. The localized corrosion processes on the DLD Mg sample surface were studied using scanning vibrating electrode technique (SVET) and scanning ion-selective electrode technique (SIET). Plasma electrolytic oxidation (PEO) method was applied to modify the DLD Mg material intended to be used as bioresorbable implants for bone repair applications. Composite polymer-containing layers were designed to increase the corrosion resistance of the protected material. It was established that the use of additive technology for the formation of the material does not require correction of the electrical modes of PEO, developed for wrought magnesium alloys. The formed coatings possess high adhesive strength and sufficiently increase the protective properties of the DLD samples in a 3 wt% NaCl solution. (C) 2019 Elsevier B.V. All rights reserved.