Influence of surface pretreatment on the chromium-free conversion coating of magnesium alloy

Zhao, Ming-Chun; Wu, Shusen; An, Ping; Ji-rong, Luo

doi:10.1016/j.matchemphys.2007.02.058

Cited by 36 publications

(6 citation statements)

References 12 publications

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“…In fact, the formation of magnesium phosphate films during etching in phosphoric acid has been previously observed 33. The following reactions have been proposed for magnesium alloys with acidic phosphate solutions33: In the first reaction, anodic dissolution of magnesium occurs because of its instability at pH values less than 11, and this is coupled with the reduction of hydrogen (reaction 2). Indeed, hydrogen bubbles were observed during etching of our samples.…”

Section: Resultsmentioning

confidence: 99%

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Influence of surface modification on the in vitro corrosion rate of magnesium alloy AZ31

Gray-Munro

Seguin

Strong

2008

J Biomedical Materials Res

150

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In recent years, magnesium alloys have been proposed as a new class of metallic bioabsorbable implant material. Unfortunately, the production of hydrogen gas and an increase in alkalinity are both by-products of the degradation process of these materials. This necessitates the development of magnesium alloys with controlled degradation rates. Furthermore, biocompatible coatings that can delay the onset of corrosion would ensure that the mechanical integrity of the implant remains intact in the early stages of healing. This article explores the influence of surface modification by biomimetic calcium phosphate coating, biodegradable polymer coatings, and acid etching on the corrosion rate of the AZ31 magnesium alloy in simulated body fluid. Our results indicate that all of these surface treatments have a positive impact on the corrosion rate of the material and that in the early stages of implantation it is possible to tailor the corrosion rate through an appropriate choice of surface treatment.

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Section: Resultsmentioning

confidence: 99%

“…32 In fact, the formation of magnesium phosphate films during etching in phosphoric acid has been previously observed. 33 The following reactions have been proposed for magnesium alloys with acidic phosphate solutions 33 :…”

Section: Influence Of Acid Etchingmentioning

confidence: 99%

Influence of surface modification on the in vitro corrosion rate of magnesium alloy AZ31

Gray-Munro

Seguin

Strong

2008

J Biomedical Materials Res

150

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“…Seeing from Figure 2(d), when the treatment time reached 5 min, an integral coating with some meshy cracks on it was formed on the specimen, which was similar with other kinds of conversion coatings [17,18]. The grinding trace couldn't be seen there, which suggested that the phytic acid conversion coating became comparatively thick and flat.…”

Section: Formation Process Of Phytic Acid Conversion Coatingmentioning

confidence: 67%

“…Surface treatments that can improve the corrosion resistance of magnesium and its alloys have been researched extensively in recently years (Gray and Luan, 2002). Surface treatment methods, such as chemical conversion treatment, is an effective and simple approach, and utilize chromate (Sharma, 1989), permanganate (Umehara et al, 2003), phosphate (Zhou et al, 2008;Li et al, 2006), and phosphate/ permanganate (Zhao et al, 2007; treatments. Chromate conversion treatment is the conventional chemical conversion method, which has been used widely in industry for many years.…”

Section: Introductionmentioning

confidence: 99%

Formation process and properties of phytic acid conversion coatings on magnesium

Liu

Guo

Huang

2012

Anti-Corrosion Methods and Materials

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“…In the traditional process, chromate conversion coatings can also provide good corrosion resistance on magnesium alloys. However, the Cr(VI) ion is so toxic to the human body and the environment that its application is severely restricted (Bierwagen et al, 2010;Zhao et al, 2007). In consequence, it is very necessary to develop new chemical conversion film technologies that are free from chromate to replace the use of Cr(VI) ions for magnesium alloy coatings to meet the needs of industry.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of a cerium conversion film on magnesium alloy

Sun

Wang

2015

Anti-Corrosion Methods and Materials

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Purpose -The purpose of this paper was to prepare the cerium-based conversion coating on AZ91D magnesium alloy, and its compositions, micro-morphology, corrosion resistance and the chemical valence state of the film elements were investigated. Design/methodology/approach -The methodology comprised preparation of coatings at different temperatures, which then were characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, an electrochemistry workstation and by means of X-ray photoelectron spectroscopy. Findings -The conversion coating had a micro-cracked morphology. The conversion coatings were composed of MgO (or Mg-OH), CeO 2 and Ce2O 3 . The best corrosion resistance of the cerium passivation film appeared when the treatment temperature was about 35°C. Originality/value -The corrosion current densities of conversion coatings were lower by one to two orders of magnitude than the corrosion current density of the blank sample. The rare earth passivation coating prepared under the best condition could reduce the corrosion current to 3.548 ϫ 10 Ϫ6 A/cm 2 .

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Influence of surface pretreatment on the chromium-free conversion coating of magnesium alloy

Cited by 36 publications

References 12 publications

Influence of surface modification on the in vitro corrosion rate of magnesium alloy AZ31

Influence of surface modification on the in vitro corrosion rate of magnesium alloy AZ31

Formation process and properties of phytic acid conversion coatings on magnesium

Preparation and characterization of a cerium conversion film on magnesium alloy

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