Improving the corrosion properties of magnesium AZ31 alloy GTA weld metal using microarc oxidation process

Prasad, M. Siva; Ashfaq, Mohammed; Babu, N. Kishore; Sreekanth, Anandaram; Sivaprasad, K.; Muthupandi, V.

doi:10.1007/s12613-017-1438-x

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…It has been reported that the coating defects (pores, cracks and etc.) and thickness are the most dominant factors that can affects corrosion properties of PEO coatings [18,27,28]. Therefore, the superior corrosion resistance of S176 sample in comparison with S576 sample is reasonable.…”

Section: Resultsmentioning

confidence: 96%

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Rahimi¹,

Yarmand²,

Kolahi³

2020

Surf. Topogr.: Metrol. Prop.

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Plasma electrolytic oxidation (PEO) coatings were formed on cast A356 aluminum alloy by applying various process parameters (current density, duty cycle and processing time) in silicate based electrolyte. The phase composition of coatings was analyzed by x-ray diffraction (XRD), surface and cross section morphology and microstructure of coatings were characterized by scanning electron microscope (SEM). The Results of x-ray diffraction showed that all coatings are composed of gamma alumina. Coating produced in higher current density, duty cycle and time was more compact with fewer amounts of defects. Thickness and roughness of coatings surfaces were measured by Eddy current gauge and surface roughness tester, respectively. The thickness of the Coatings was in the range of 3–7 μm and it increased by increasing current density and time, but duty cycle did not have a noticeable effect on it. Corrosion resistance of bare and coated samples was evaluated by polarization test in 3.5 wt% NaCl solution. Sample S176 showed the best corrosion resistance with corrosion current density of 4.17 × 10−8 A.cm−2 and polarization resistance of 6.31 × 105 Ω.cm2 that attributed to its more dense structure.

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Section: Resultsmentioning

confidence: 96%

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Rahimi¹,

Yarmand²,

Kolahi³

2020

Surf. Topogr.: Metrol. Prop.

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“…However, due to their inherent strong electronegative potential, magnesium alloys are relatively poor from the point of view of corrosion resistance, which limits their use in harsh environments [4,5]. So, there are many surface technologies available for the coating of magnesium and its alloys, including conversion coating, electrochemical plating, anodising and vapour phase processes, protecting alloys from corrosive environments during service [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effect of cathode pulse square-wave on the microstructure and corrosion resistance of PEO coatings of AZ91D magnesium alloy prepared in the Na₂C₄H₄O₆–KF–Na₂SiO₃ system

Meng

Zhang

et al. 2022

Corrosion Engineering, Science and Technology

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Plasma electrolytic oxidation coatings were formed in Na 2 C 4 H 4 O 6 -KF-Na 2 SiO 3 system on AZ91D magnesium alloy by controlling the single-pulse square-wave and bipolar pulse square-wave, respectively. Potentiodynamic polarisation (PD), electrochemical impedance spectroscopy (EIS) and electrochemical noise measurement (EN) were employed to investigate their corrosion behaviour in 3.5% NaCl solution. The results show that with bipolar pulse mode for PEO process, the growth rate of PEO coating on magnesium alloy first decreased and some micropores were present inside the PEO coating. With the increasing oxidation time, the PEO coating became much homogeneous and the porosity of the coating decreased largely, and the corrosion resistance of PEO coating was enhanced. The use of the bipolar pulse mode is beneficial to the improvement of the compactness and corrision performance of magnesium alloy with PEO treatment for the higher voltage stage and longer oxidation time.

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“…Furthermore, the effects of post-treatments on PEO coated magnesium alloys were evaluated in terms of characterisation and corrosion resistance [34]. However, very few literatures are available in corrosion studies on friction stir welded magnesium alloy thin plates [35,36]. Hence, in the present research work, corrosion behaviour of friction stir welded rare earth magnesium alloy ZE41 thick plates treated with plasma electrolytic oxidation process has been examined.…”

Section: Introductionmentioning

confidence: 99%

Influence of plasma electrolytic oxidation coating on corrosion characteristics of friction stir welded ZE41 rare earth magnesium alloy

Sivashanmugam¹,

Harikrishna²,

Rao³

et al. 2021

Surf. Topogr.: Metrol. Prop.

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Magnesium and its alloys are extensively used in the defence, aerospace and automotive industries, owing to their excellent mechanical properties. But there is a requirement of corrosion prevention treatment before using it for applications, since the corrosion resistance of Mg alloy is poor. In this work, a study on the mechanical properties of friction stir welded ZE41 rare earth magnesium alloy thick plates of 15mm and 25mm, was carried out. A metallographic examination and mechanical tests were conducted on both the welds. Furthermore, Plasma Electrolytic Oxidation (PEO), a surface conversion treatment was carried out on both the base material as well as on the friction stir butt joints. X-ray diffraction and scanning electron microscopy analysis were carried out on all the samples, with and without coating. The coated and uncoated samples were assessed by potentiodynamic polarisation (PDP) tests and electrochemical impedance spectroscopy (EIS) to study the electrochemical corrosion behaviour. An outer porous layer and an inner dense layer, have been identified from the SEM images. From the corrosion tests results it was revealed that there was an improvement in the corrosion resistance of both the base metal as well as the weldments by the PEO coating process.

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Improving the corrosion properties of magnesium AZ31 alloy GTA weld metal using microarc oxidation process

Cited by 10 publications

References 22 publications

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Effect of cathode pulse square-wave on the microstructure and corrosion resistance of PEO coatings of AZ91D magnesium alloy prepared in the Na₂C₄H₄O₆–KF–Na₂SiO₃ system

Influence of plasma electrolytic oxidation coating on corrosion characteristics of friction stir welded ZE41 rare earth magnesium alloy

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Improving the corrosion properties of magnesium AZ31 alloy GTA weld metal using microarc oxidation process

Cited by 10 publications

References 22 publications

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Effect of cathode pulse square-wave on the microstructure and corrosion resistance of PEO coatings of AZ91D magnesium alloy prepared in the Na2C4H4O6–KF–Na2SiO3 system

Influence of plasma electrolytic oxidation coating on corrosion characteristics of friction stir welded ZE41 rare earth magnesium alloy

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Effect of cathode pulse square-wave on the microstructure and corrosion resistance of PEO coatings of AZ91D magnesium alloy prepared in the Na₂C₄H₄O₆–KF–Na₂SiO₃ system