Degradation Behavior of Coatings Formed by the Plasma Electrolytic Oxidation Technique on AZ61 Magnesium Alloys Containing 0, 1 and 2 wt% Ca&#x0D;

Anawati, Anawati; Asoh, Hidetaka; Ono, Satoshi

doi:10.14716/ijtech.v9i3.712

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…After the chemical treatments, the specimen was first washed thoroughly with DI water and then dried. The procedure for acid-alkaline treatment used in previous research was utilized as pretreatment for the growth of composite conversion coatings [12][13][14].…”

Section: Experimental Methodsmentioning

confidence: 99%

Improving the Surface Corrosion Resistance of AMX601 Magnesium Alloy by Acid–Alkaline Treatment

2020

Makara J. Sci.

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A drawback of acid cleaning as surface finishing of magnesium (Mg) surface is the absence of a protective oxide film on its surface. Acid-alkaline treatment is proposed to enhance the surface corrosion resistance of AMX601 Mg alloy. Acid-alkaline treatment was conducted by first dipping the alloy in HNO 3-H 3 PO 4 solution and then immersing the alloy in NaOH solution. The potentiodynamic polarization test in 0.9% NaCl solution at 37°C revealed a nobler corrosion potential of −1.36 V Ag/AgCl and a lower corrosion current density of 36.0 µA•cm −2 of the acid-alkaline-treated specimen than the acid-treated (−1.44 V Ag/AgCl , 89.7 µA•cm −2) and untreated (−1.52 V Ag/AgCl , 40.0 µA•cm −2) specimens. Acid treatment induced a significantly higher surface roughness (20 µm) than acid-alkaline (10 µm) and grinding (0.5 µm) treatments because of the selective dissolution of the Mg matrix and the accumulation of intermetallic precipitates. The film formed on the acid-alkaline-treated specimen was thick and free of cracks, whereas that formed on the acid-treated specimen was thin and cleaved. The formation of a protective oxide film and the enrichment of cathodic intermetallic particles on the acid-alkaline-treated specimen enhanced the corrosion resistance of the surface.

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Section: Experimental Methodsmentioning

confidence: 99%

Improving the Surface Corrosion Resistance of AMX601 Magnesium Alloy by Acid–Alkaline Treatment

2020

Makara J. Sci.

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“…Pt wire was used as a counter electrode, and silver chloride (Ag/AgCl) was used as a reference electrode. The electrochemical cell condition and arrangement were similar to as reported earlier [24]. Potentiodynamic polarization test was conducted from 100 mV below open circuit potential (OCP) and terminated when the current output reached 30 mA at a sweep rate of 1 mV·s −1 .…”

Section: Methodsmentioning

confidence: 99%

“…An embodiment of Ca in the coating and its presence in the alloy accelerated the growth of apatite in simulated body fluid (SBF). However, short-term (8 min) grown coatings on Mg–6Al–1Zn–xCa alloys revealed no bioactivity in SBF and significantly high corrosion rate [24]. The reason for such behavior was still unclear.…”

Section: Introductionmentioning

confidence: 99%

Corrosion Resistance and Apatite-Forming Ability of Composite Coatings formed on Mg–Al–Zn–Ca Alloys

2019

Self Cite

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The properties of composite coatings formed by plasma electrolytic oxidation (PEO) were affected by the alloy composition. The corrosion resistance and apatite-forming ability of PEO coatings formed on Mg–6Al–1Zn–xCa alloys with a variation of Ca content were investigated. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements showed an order magnitude improvement of corrosion resistance in the AZ61 alloy as a result of the coating. A higher enhancement in polarization resistance was obtained in the Mg–6Al–1Zn–1Ca and Mg–6Al–1Zn–2Ca alloys due to thicker coatings were formed as a result of the incorporation of calcium oxide/hydroxide. However, the underlying substrates were more prone to localized corrosion with increasing Ca content. The microstructure investigation revealed an enlargement in precipitates (Al2Ca, Mg2Ca) sizes with increasing Ca content in the alloys. The growth of larger size precipitates increased the danger to micro galvanic corrosion. Apatite layers were formed on all of the coatings indicating high apatite-forming ability, but the layers formed on the Mg–6Al–1Zn–1Ca and Mg–6Al–1Zn–2Ca alloys contained higher Mg, possibly due to the accumulation of corrosion product, than that on the Mg–6Al–1Zn alloy. The alloying element Ca should be limited to 1 wt.% as the excess tended to degrade the corrosion resistance and apatite-forming ability of the PEO coating.

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“…Hence, researchers have conducted studies on the effect of Sm addition to various magnesium systems such as Mg-6.0Zn-0.5Zr alloy (ZK60) (Guan et al, 2018), Mg-11Gd-2Y-0.6Al (Chen et al, 2019), Mg-Al-Zn (AZ61) (Anawati, Asoh, and Ono, 2018;Chen et al, 2015) Al-Zr-Ce (Kirman, Zulfia, and Suharno, 2016) and Mg-5Y-2Nd-0.5Zr (Yunwei et al, 2018). It is found the application of 1.5 wt.% Sm additive in Mg-6.0Zn-0.5Zr alloy (ZK60) refined the grains of the as-cast sample, while the extruded sample shows even finer (Guan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Magnesium ZRE1 (Mg-Zn-Zr) Alloy with Rare Earth Element (Samarium) Addition

Tukiat,

Yusuf,

Khaireez

et al. 2024

IJTech

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The influences of rare earth (RE) samarium (Sm) added contents to ZRE1 (Mg-Zn-Zr) magnesium (Mg) cast alloy over strength properties to be investigated. Sm at 0.5, 1.0, 1.5, and 2.0 wt.% were added separately as an alloying element to ZRE1 alloy. Optical Microscope (OM), X-ray powder diffraction (XRD), and scanning electron microscope Energy-dispersive X-ray (SEM/EDS) were used to investigate the microstructure of alloy, while mechanical properties investigated include Ultimate Tensile Strength (UTS)and Micro-Hardness (MH) tests. The result revealed that as the Sm level reached 1.5 wt.%, the grain size decreased by 20.9 %. Additionally, UTS and Yield Strength (YS) showed improvements of 8.5 % and 7.9 %, respectively, with the addition of 1.5 wt.% of Sm. In addition, elongation and hardness have been improved by 32.3 % and 10.9 % respectively at 1.5 wt.% Sm addition. Mg-Zn-Ce-Sm was formed as a new phase upon the addition of Sm and was detected via XRD analysis. The addition of Sm to the ZRE1 alloy had significant effects on the refinement of the material's microstructure, leading to an increase in its mechanical and physical properties. Therefore, the new ZRE1-RE magnesium alloy was developed.

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Degradation Behavior of Coatings Formed by the Plasma Electrolytic Oxidation Technique on AZ61 Magnesium Alloys Containing 0, 1 and 2 wt% Ca

Cited by 7 publications

References 12 publications

Improving the Surface Corrosion Resistance of AMX601 Magnesium Alloy by Acid–Alkaline Treatment

Improving the Surface Corrosion Resistance of AMX601 Magnesium Alloy by Acid–Alkaline Treatment

Corrosion Resistance and Apatite-Forming Ability of Composite Coatings formed on Mg–Al–Zn–Ca Alloys

Microstructure and Mechanical Properties of Magnesium ZRE1 (Mg-Zn-Zr) Alloy with Rare Earth Element (Samarium) Addition

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