Electrochemical corrosion properties of CeO2-containing coatings on AZ31 magnesium alloys prepared by plasma electrolytic oxidation

A study on microstructure and corrosion resistance of ZrO2-containing PEO coatings formed on AZ31 Mg alloy in phosphate-based electrolyte

“…The extracted potentiodynamic parameters are listed in Table 4. It is showed that the E corr and i corr of the AZ31 Mg alloy substrate are registered as -1.57 V (vs. SCE) and 86.74 μA/cm 2 , respectively, which are approximately in accordance with those found in literature [11,24,25]. After the PEO treatment, all the coatings exhibited a more positive E corr and a much lower i corr than that of uncoated AZ31 Mg alloy substrate.…”

“…Liang et.al [6] have demonstrated that ZrO 2 coating formed in K 2 ZrF 6 solution could offer a quite longer time protection to the magnesium alloy substrate than traditional PEO coatings fabricated in alkaline phosphate electrolyte due to the higher chemical stability of ZrO 2 . Liu et.al [11] have found that the elements distribution in the PEO coating produced in K 2 ZrF 6 -containing is inhomogeneous, and the content of MgF 2 is high in the pores and an MgO-rich layer is evident in the layer near to the Mg substrate. Luo et.al [13] proved that the ZrO 2 -containing ceramic coatings fabricated in K 2 ZrF 6 -NaSiO 3 -KOH electrolyte showed the most superior anti-corrosion properties than that of the other two electrolytes, i.e., Zr(NO 3 ) 4 -KOH electrolyte and ZrOCl 2 -KOH electrolyte, because of its uniform surface, a compact inner layer and the maximum thickness and some corrosion resistance phases.…”

“…Plasma electrolytic oxidation (PEO), derived from the traditional anodic oxidation, is one of the effective technique to produce ceramic coating with good corrosion resistance and wear resistance on magnesium alloys. The properties of PEO coatings were mainly characterized by electric parameters [3][4][5], chemical composition of electrolyte [6][7][8], substrate material [9], electrolyte additives [10][11][12].…”

Anodic Oxide Films Formed on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation Method in Electrolytes Containing Various NaF Concentrations

“…The composition and corrosion resistance of PEO films on Mg alloys have been known to be largely dependent upon the solution composition and concentration. PEO treatment of Mg alloys has been conducted in many different aqueous electrolytes containing silicates [4,[14][15][16], fluorides [5,8], phosphates, borates and stannite electrolytes. Verdure et al [17] reported that all the elements in the electrolytes could be included in the PEO films on AM60 Mg alloy.…”

Effects of Hydroxide and Silicate ions on the Plasma Electrolytic Oxidation of AZ31 Mg Alloy

“…The composition and corrosion resistance of PEO films on Mg alloys have been known to be largely dependent upon the solution composition and concentration. PEO treatment of Mg alloys have been conducted in many different aqueous electrolytes containing silicates 5,6,[15][16][17] , fluorides 10,11,18) , phosphates 3,19) , borates 20) and stannate electrolytes 21) . Verdier et al…”