Electrochemical corrosion behaviour of plasma electrolytic oxidation coatings on AM50 magnesium alloy formed in silicate and phosphate based electrolytes

Liang, Jun; Srinivasan, P. Bala; Blawert, Carsten; Störmer, M.; Dietzel, W.

doi:10.1016/j.electacta.2009.02.004

Cited by 288 publications

(124 citation statements)

References 26 publications

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“…Even though PEO of magnesium alloys can be accomplished in many different electrolytes, silicate and phosphate based electrolytes are the most widely employed electrolytes even today [19][20][21][22][23][24]. In our previous work [21], the electrochemical behaviour of PEO coated AM50 magnesium alloy produced from silicate and phosphate electrolytes in 0.1 M NaCl solution was reported.…”

Section: Introductionmentioning

confidence: 99%

“…In our previous work [21], the electrochemical behaviour of PEO coated AM50 magnesium alloy produced from silicate and phosphate electrolytes in 0.1 M NaCl solution was reported. It was found that the corrosion resistance of the PEO coating formed in the silicate electrolyte was superior to that formed from the phosphate electrolyte, which was related to the microstructure and composition of the PEO coatings.…”

Section: Introductionmentioning

confidence: 99%

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Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

Liang

Srinivasan

Blawert

et al. 2010

Electrochimica Acta

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141

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The electrochemical degradation of a silicate-and a phosphate-based plasma electrolytic oxidation (PEO) coated AM50 magnesium alloy obtained using a pulsed DC power supply was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in NaCl solutions of different chloride ion concentrations viz., 0.01M, 0.1M, 0.5M and 1M. The surface of the PEO coated specimens after 50 h of immersion/EIS testing was examined by optical microscopy and scanning electron microscopy. The results showed that the corrosion deterioration of PEO coated magnesium alloy in NaCl solutions was significantly influenced by chloride ion concentration. The silicate-based coating was found to offer a superior corrosion resistance to the magnesium substrate than the phosphate based coatings in lower chloride ion concentration NaCl solutions (0.01 M and 0.1 M NaCl). On the other hand both these PEO coatings were found to be highly susceptible to localized damage, and could not provide an effective corrosion protection to Mg alloy substrate in solutions containing higher chloride concentrations (0.5 M and 1 M). The extent of localized damage was observed to be more with increase in chloride concentration in both the cases.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

Liang

Srinivasan

Blawert

et al. 2010

Electrochimica Acta

Self Cite

141

View full text Add to dashboard Cite

show abstract

“…Plasma electrolytic oxidation (PEO) method is one of the promising surface treatment methods for Mg alloys. The PEO treatment method is used to form an anodic oxide film on valve metals using micro arcs generated by dielectric breakdown of the oxide film under high electric field [1][2][3][4][5][6][7][8][9][10][11][12][13]. PEO film on AZ31 Mg alloy has been studied by many authors.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Moon¹,

Kwon²

2016

Journal of the Korean institute of surface engineering

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The present work was conducted to investigate the effects of NaF concentration in phosphate and silicatecontaining alkaline electrolyte on the morphology, thickness, surface roughness and hardness of anodic oxide films formed on AZ31 Mg alloy by plasma electrolytic oxidation (PEO) method. The PEO films showed flat surface morphology with pores in the absence of NaF in the electrolyte, but nodular features appeared on the PEO film surface prepared in NaF-containing electrolyte. Numerous pores ranging from 1 to 20 µm in size were observed in the PEO films and the size of pores decreased with increasing NaF concentration in the electrolyte. Surface roughness and thickness of PEO films showed increases with increasing NaF concentration. Hardness of the PEO films also increased with increasing NaF concentration. It was noticed that hardness of inner part of the PEO films is lower than that of outer part of them, irrespective of the concentration of NaF. The low hardness of PEO films was explained by the presence of a number of small size pores less than 2 µm near the PEO film/substrate interface.

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“…There are a number of studies on PEO coatings of magnesium alloys for corrosion protection. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] The composition, thickness and morphology of the PEO coatings are dependent upon various parameters including electrolyte composition, current density, applied voltage and current wave form. 15,[21][22][23][24] Pulsed DC or AC mode of anodizing is generally used, instead of simple DC anodizing, due to wider possibility of controlling the PEO process.…”

Section: Introductionmentioning

confidence: 99%

Influence of Phosphate Concentration on Plasma Electrolytic Oxidation of AZ80 Magnesium Alloy in Alkaline Aluminate Solution

2010

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Plasma electrolytic oxidation of AZ80 magnesium alloy in alkaline aluminate electrolytes develops MgAl 2 O 4 -based highly crystalline oxide coatings with the morphology changing largely with phosphate concentration in electrolyte. The thickness of the coatings increases with phosphate concentration from 5 mm in phosphate-free electrolyte to $70 mm in the electrolyte containing 0.1 molÁdm À3 phosphate after anodizing for 900 s. The formation of the latter thick coating is associated with intense sparking during anodizing. The thick coatings formed in the electrolytes containing 0.075 and 0.1 molÁdm À3 phosphate are highly cracked. In contrast, the coating formed in the electrolyte containing 0.05 molÁdm À3 phosphate is relatively uniform, showing the highest corrosion protection in 0.5 molÁdm À3 NaCl solution. The coatings consist of two layers, comprising an outer thick layer with high concentration of aluminum and an inner thin magnesium-rich layer.

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Electrochemical corrosion behaviour of plasma electrolytic oxidation coatings on AM50 magnesium alloy formed in silicate and phosphate based electrolytes

Cited by 288 publications

References 26 publications

Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

Influence of chloride ion concentration on the electrochemical corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy

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

Influence of Phosphate Concentration on Plasma Electrolytic Oxidation of AZ80 Magnesium Alloy in Alkaline Aluminate Solution

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