Characterization and corrosion behavior of ceramic coating on magnesium by micro-arc oxidation

Corrosion behavior of a self-sealing pore micro-arc oxidation film on AM60 magnesium alloy

“…Spark discharge occurs first at the weak locations of the films (such as defects and thin sites) during the increase of oxidation voltages [16,17]. Plasma groups flow out through the discharge channels, similar to a volcanic eruption, and then are cooled rapidly by the solution [18]. The molten components are deposited on both film surface and pore walls [15].…”

“…All magnesium ions in the film come from the dissolution of Mg substrate [22]. The dissolved Mg 2+ ions from Mg substrate migrate outward, while F -and O 2-migrate inward in the discharge channels under the effect of electrical field [18]. These ions react with each other in the discharge channels to form MgO and MgF 2 , and then they are erupted outside.…”

Degradation behavior of n-MAO/EPD bio-ceramic composite coatings on magnesium alloy in simulated body fluid

“…MAO is a novel and unique surface modification technique based on anodic oxidation, which enables to produce a corrosion resistant coating with dense, well-adhered and wear resistant on the surface of Mg based materials in a suitable electrolyte [12][13][14]. Some researchers have proven that the MAO coating can improve corrosion resistance of Mg alloys substrate [14][15][16][17][18][19][20][21][22]. Durdua et al [15] reveal that the MAO coating produced on pure Mg in silicate electrolyte has higher corrosion resistance than that of produced in phosphate electrolyte in 3.5 wt.% NaCl.…”

“…Some researchers have proven that the MAO coating can improve corrosion resistance of Mg alloys substrate [14][15][16][17][18][19][20][21][22]. Durdua et al [15] reveal that the MAO coating produced on pure Mg in silicate electrolyte has higher corrosion resistance than that of produced in phosphate electrolyte in 3.5 wt.% NaCl. Wang et al [16] found that the MAO coating was produced on AZ91 alloy obviously slowing down the biodegradation rate compare with AZ91 alloy substrate in the SBF.…”

Hemocompatibility and selective cell fate of polydopamine-assisted heparinized PEO/PLLA composite coating on biodegradable AZ31 alloy

“…However, although providing good protection and enhanced surface biocompatibility for the magnesium substrate, the polymer coatings did not maintain a reduction in corrosion rate over the long term and the inhomogeneous coating durability with gas pocket formation in the polymer coating will result in eventual detachment from the alloy surface [13]. Plasma electrolytic oxidation (PEO), also called micro arc oxidation (MAO), has been widely used to fabricate protective ceramic coatings on magnesium substrates in industrial applications [14,15]. As used in biomedical application, the PEO coatings can be conveniently adjusted to be non-toxic by dislodging the potential toxic addition in electrolytes [16].…”