Influence of Heat Treatment Temperature on Corrosion Characteristics of Biodegradable EW10X04 Mg Alloy Coated with Nd

Abstract

The effect of heat treatment temperature (150, 350, and 550 C) on corrosion of biodegradable EW10X04 Mg alloy coated with Nd was tested in PBS solution. The microstructure was examined by SEM, XRD, and XPS analysis and corrosion resistancewas evaluated by immersion test, potentiodynamic polarization and EIS analysis. Comparatively the complex microstructure of the surface obtained after heat treatment at 350 C has the best corrosion resistance. This was mainly due to the formation of a nearly continuous network of Mg 41 Nd 5 that acts as a protective barrier around a-Mg grains. The heat treatment at 150 C was not effective in creating a similar protective network. In the heat treatment at 550 C, a new intermetallic phase (Mg 3 Nd) was formed having a detrimental effect on corrosion resistance.

Effect of Thermal Oxidation on Microstructure and Corrosion Behavior of the PVD Hf‐Coated Mg Alloy

“…The binding force between the coating and the substrate is a critical factor for deciding on the anticorrosion performance of coating. In addition, the heat treatment temperature and adhesion and the corrosion resistance are intimately related . Hence, the adhesion of the as‐deposited and treated coating on Mg alloys was estimated using a cross cut adhesion test according to ASTMD3359‐02.…”

“…Due to their low weight, good electrical conductivity, and biocompatible property, magnesium (Mg) alloys have been widely used in automotive, biomedical industries, and polymer electrolyte membrane fuel cells . However, Mg alloys exhibit the highest chemical reactivity among the construction materials (steel, aluminum, and titanium alloys) .…”

“…Keeping the above mentioned information in mind, pre‐ or post‐treatments have been conducted to solve coating defects to further improve their service quality . Thermal oxidation treatment has been highly praised as an efficient and feasible post‐treatment for enhancing the corrosion resistance of coatings (including PVD and other coatings) . Generally, the barrier oxide layer was deliberately generated on the metal surface during an in situ thermal oxidation treatment, which enhanced corrosion or wear resistance .…”

“…Generally, the barrier oxide layer was deliberately generated on the metal surface during an in situ thermal oxidation treatment, which enhanced corrosion or wear resistance . The low melting coating, such as aluminum or neodymium, formed the intermetallic phase with Mg alloys, which acted as a protective barrier for the substrates . Regarding the refractory coating, the influence of thermal oxidation on the coating's microstructure, composition, and corrosion property was complex.…”