Phosphating process of AZ31 magnesium alloy and corrosion resistance of coatings

Cheng, Yingliang; Wu, Hai-lan; Chen, Zhenhua; Wang, Huimin; Li, Lingling

doi:10.1016/s1003-6326(06)60382-8

Cited by 39 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zinc phosphate improves the corrosion resistance relative to a simple phosphate coating [17,18,42,45,47]. Higher corrosion potentials are obtained with zinc phosphate baths ( Table 4).…”

Section: -mentioning

confidence: 99%

Corrosion Protection of Magnesium Alloys: From Chromium VI Process to Alternative Coatings Technologies

Frayret¹,

Dupin²,

Pommiers³

2017

Magnesium Alloys

View full text Add to dashboard Cite

Magnesium and its alloys present several advantages such as a high strength/weight ratio and a low density. These properties allow them to be used for many aeronautical applications but they are very sensitive to corrosion. In order to solve this problem, chromium VI conversion coatings (CCC) are deposited on the surface before a protective top coat application. This process is now limited by several environmental laws due to the high toxicity of hexavalent chromium. However the chemical mechanisms of CCC deposition will be detailed in this chapter in order to understand the chemical properties of this coating. Pre-treatment steps allow cleaning and preparing the surface for improving the coating deposition. A final layer of chromium (III) oxide and magnesium hydroxide composes the coating allowing the protective properties. Orthorhombic potassium chromate clusters trapped on the coating surface give self-healing property to the coating. Alternative conversion coatings are based onto solutions containing chromium (III), permanganate, phosphates, Rare Earth Elements (REEs) or vanadium. The second part of this chapter will detail the deposition and the protection mechanisms of these promising processes of CrVI substitution. Among them, permanganate/phosphate-based coating presents a better corrosion resistance than CCC and REEs have very efficient self-healing properties.

show abstract

“…Zinc phosphate improves the corrosion resistance relative to a simple phosphate coating [17,18,42,45,47]. Higher corrosion potentials are obtained with zinc phosphate baths ( Table 4).…”

Section: -mentioning

confidence: 99%

Corrosion Protection of Magnesium Alloys: From Chromium VI Process to Alternative Coatings Technologies

Frayret¹,

Dupin²,

Pommiers³

2017

Magnesium Alloys

View full text Add to dashboard Cite

show abstract

“…This work proposes the use of an intermediary conversion layer of magnesium alloy, combined with a hybrid sol-gel film. This layer was produced by the treatment of the samples with phosphoric acid, in order to form phosphate-based compounds, chemically more stable than the magnesium metallic surface [8,10,11,14]. The characteristics of the produced conversion layers are described hereinafter.…”

Section: Sol-gel Coating Without Conversion Filmmentioning

confidence: 99%

“…These films are composed of insoluble and stable compounds that protect the metallic substrate from corrosive species. These conversion treatments generally include the use of phosphates [8][9][10][11][12][13], phosphate-permanganate [14,15], fluorides [16][17][18][19][20][21][22][23] and rare earths [24][25][26]. However, the protection afforded by many of these coatings is limited, and generally they are used as a support base for additional coatings, like paints or/and other organic coatings [27].…”

Section: Introductionmentioning

confidence: 99%

Protection against corrosion of magnesium alloys with both conversion layer and sol–gel coating

Murillo-Gutiérrez

Ansart

Bonino

et al. 2013

Surface and Coatings Technology

View full text Add to dashboard Cite

The anticorrosion performances of a system consisting of a phosphate based conversion layer and a hybrid sol-gel coating have been evaluated for the magnesium alloy Elektron21. The lone sol-gel coating affords a significant protection of the magnesium substrate. However, the presence of an intermediate conversion layer is presumed to improve the corrosion resistance of the system. The surface morphology of the protection coatings was characterized by optical microscopy, scanning electron microscopy (SEM) and white-light source interferometry. The corrosion behavior of the systems was analyzed by electrochemical impedance spectroscopy (EIS). The impedance measurements show that the presence of the added conversion layer increases the resistance of the whole system during immersion in a 0.05 M NaCl solution, compared to the single sol-gel coating.

show abstract

“…Various chemical conversion coatings and anodic oxidation layers have been selected for the protection of magnesium alloys from corrosion in our group. The phosphating processes of AZ31 and ZK60 and corrosion resistance of the coatings were studied respectively [31,32]. The results showed that the chemical conversion layers were not effective in preventing magnesium alloys from corrosion.…”

Section: Surface Modification Of Magnesium Alloysmentioning

confidence: 99%

A review: Hot topics on magnesium technology in China

Chen

2008

Front. Mater. Sci. China

Self Cite

View full text Add to dashboard Cite

Magnesium alloys have wide applications in automobiles, aerospace and so on due to many advantages, while a number of undesirable properties including poor corrosion resistance, inferior creep resistance and bad plastic processing ability have hindered their applications. Creep-resistant magnesium alloy design, plastic processing of magnesium alloys and rapid solidification processing of magnesium alloys have become the hot topics in magnesium technology. Other than these, surface modification as well as laser beam welding are also involved. The research progress and development in magnesium technology in China are reviewed in the paper.

show abstract

Phosphating process of AZ31 magnesium alloy and corrosion resistance of coatings

Cited by 39 publications

References 15 publications

Corrosion Protection of Magnesium Alloys: From Chromium VI Process to Alternative Coatings Technologies

Corrosion Protection of Magnesium Alloys: From Chromium VI Process to Alternative Coatings Technologies

Protection against corrosion of magnesium alloys with both conversion layer and sol–gel coating

A review: Hot topics on magnesium technology in China

Contact Info

Product

Resources

About