Comparative study of different environmentally friendly (Chromium-free) methods for surface modification of pure magnesium

Zuleta, Alejandro; Correa, Esteban; Villada, Carolina; Sepúlveda, Marcela; Castaño, Juan G.; Echeverría, Félix

doi:10.1016/j.surfcoat.2011.05.048

Cited by 29 publications

(12 citation statements)

References 43 publications

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“…These coatings are developed in an aqueous solution at high voltage leading to the local formation of plasma discharges at the metal surface converting part of it into a ceramic-like coating as a result of interaction with components of electrolyte [3,4]. Many studies have utilized wide range of chemical compositions and concentrations of electrolytes, different electrical parameters and processing time for PEO coating on magnesium alloys [5][6][7][8][9]. Among these parameters, the composition and concentration of electrolyte have an important impact on the final coating morphology, composition and performance.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Degradation behavior of PEO coating on AM50 magnesium alloy produced from electrolytes with clay particle addition

Sah

Scharnagl

et al. 2015

Surface and Coatings Technology

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Section: Accepted Manuscriptmentioning

confidence: 99%

Degradation behavior of PEO coating on AM50 magnesium alloy produced from electrolytes with clay particle addition

Sah

Scharnagl

et al. 2015

Surface and Coatings Technology

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“…For this reason, surface tratments are needed in order to improve the surface properties and thereby extend the use of magnesium and its alloys. Various processes, such as electrodepostion [5][6][7], electroless coating [8][9][10][11][12], conversion coating [13][14][15], microarcoxidation [16,17], gas-phase deposition [18,19], surface laser modification [20], and the combination of two or more of the mentioned approaches, have been used to improve the surface performance of the alloys; among these, electroless Ni-P plating offers the possibility of generating uniform, crack-free, and well-adhered coatings, without the need of an external power source [21,22].…”

Section: Introductionmentioning

confidence: 99%

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

Zuleta

Correa

Castaño

et al. 2017

Surface and Coatings Technology

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In this work, alkaline electroless Ni-P coatings were directly formed on commercial purity magnesium and AZ31B magnesium alloy substrates using a process that avoided the use of Cr(VI) compounds. The study focused on two aspects of coating formation: (i) the effect of the substrate roughness on the kinetics of the electroless Ni-P deposition process on magnesium; (ii) the morphological and chemical evolution of the coating on both magnesium and the AZ31B alloy. For these purposes, gravimetric measurements, scanning electron microscopy (SEM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and open-circuit potential (OCP) measurements were employed. It is shown that a relatively rough substrate promotes the rapid formation of the Ni-P coating on the substrate surface in comparison with smoother substrates. Furthermore, the presence of fluoride ions derived from the NH 4 HF 2 reagent in the electroless Ni-P plating bath leads to formation of MgF 2 a few seconds after immersion in the bath; the MgF 2 . Subsequently, crystals of NaMgF 3 , with a cubic morphology, are developed, which later become embedded in the Ni-P matrix. The presence of fluorine species passivates the substrate during coating formation and hence restricts the decomposition of the electroless Ni-P plating bath, which can occur due to release of Mg 2+ ions. Finally, according to gravimetric measurements, SEM and XRD, the plating process is initially faster on magnesium than on the alloy.

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“…The high frequency capacitance loop is related to the characteristics of the electric double layer at the interface of substrate (or HT¯lm) and solution, while the low frequency inductive loop is attributed to adsorption of corrosion products on the substrate surface. 29 The medium frequency capacitive loop is connected with HT¯lm on the Mg-Gd-Zn alloy. Higher jZj value represents better corrosion resistance.…”

Section: Corrosion Behaviormentioning

confidence: 99%

FORMATION AND CORROSION RESISTANCE OF Mg–Al HYDROTALCITE FILM ON Mg–Gd–Zn ALLOY

Dong

Kong

et al. 2016

Surf. Rev. Lett.

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An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg 6 Al 2 (OH) 16 -CO 3 Á 4H 2 O) conversion¯lm was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the¯lm were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray di®raction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT¯lm in the simulated body°uid (SBF). It was found that the formation of Mg-Al HT¯lm was a transition from amorphous precursor to a crystalline HT structure. The HT¯lm can e®ectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

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Comparative study of different environmentally friendly (Chromium-free) methods for surface modification of pure magnesium

Cited by 29 publications

References 43 publications

Degradation behavior of PEO coating on AM50 magnesium alloy produced from electrolytes with clay particle addition

Degradation behavior of PEO coating on AM50 magnesium alloy produced from electrolytes with clay particle addition

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

FORMATION AND CORROSION RESISTANCE OF Mg–Al HYDROTALCITE FILM ON Mg–Gd–Zn ALLOY

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