June 15, 2021

Download Ebook Free Corrosion Prevention Of Magnesium Alloys

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : X.-P. Guo,G.-L. Song,J.-Y. Hu,D.-B. Huang
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Addition of inhibitors in service environments is a practical corrosion protection approach for engineering materials in industry. This chapter provides an overview of corrosion inhibition of magnesium (Mg) alloys. After a summary of inhibitor inhibition mechanisms on Mg, a few case studies on inhibitor selection and inhibition efficiency evaluation for Mg and its alloys in various media are presented. Based on promising results, future work in this area is proposed.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : G.S. Cole
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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This chapter discusses magnesium corrosion with particular reference to how magnesium automotive components, exposed to the automotive corrosion environment, can be protected and provide durable function. The chapter introduces the four types of corrosion that occur with automotive magnesium alloy components. The major focus is on the galvanic events associated with manufacturing and fastening between magnesium components and the steel/aluminum structures used in automotive construction. Examples of new applications, taken from the literature, are discussed with details of the protective modalities that were developed to ensure long-term vehicle durability.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : X.-B. Chen,M.A. Easton,N. Birbilis,H.-Y. Yang,T.B. Abbott
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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The escalation of ongoing research on the topic of conversion coatings for magnesium alloys confirms that the search continues for appropriate replacements to toxic chromate-based coatings. This chapter reviews the performance of the range of typical conversion coating technologies presently available. As a means to rationalise coating performance and characteristics more generally, thermodynamic analysis has been used to compare coating processes and coating pretreatment, the latter of which appears to be at least as significant as the choice of coating technology itself.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : G.-L. Song
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Magnesium (Mg) alloys have low corrosion resistance and exhibit unusual corrosion behavior in aqueous environments. Because of this unique corrosion performance, some special corrosion prevention techniques have to be employed for Mg alloys in their applications. This chapter briefly summarizes the corrosion characteristics of Mg alloys, and also presents a strategy and methodologies to mitigate the corrosion damage of Mg alloys in applications.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : K. Yang,L. Tan
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Magnesium-based metals, including pure magnesium and its alloys, are becoming increasingly popular in the medical industry due to the fact that they are biodegradable. This chapter briefly introduces the concept of biodegradable magnesium-based metals and their advantages as a new class of metallic biomaterials. Relevant research progress is summarized, especially the corrosion control of magnesium-based metals by appropriate surface modification, which is a key issue for clinical applications.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : G.-L. Song,Z. Shi
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Anodization is one of the most important and effective surface pre-treatments for Mg alloys. This chapter systematically summarizes Mg alloy anodizing behavior, the compositions and microstructures of anodized films on Mg alloys and the anodization-influencing factors. Based on the anodizing voltage variation, gas evolution and sparking behavior in a typical anodizing process and the characteristic composition and microstructure of an anodized coating, a four-stage anodizing mechanism is postulated. Moreover, the corrosion performance of anodized Mg alloys is systematically reviewed and a corrosion model is proposed to explain the corrosion performance and electrochemical behavior. It is believed that some of the measured electrochemical features can be utilized to rapidly evaluate or compare the corrosion resistance of anodized Mg alloys.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : G.-L. Song
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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A thin E-coating can be rapidly deposited on the surface of a Mg alloy in a cathodic E-coating bath without applying any current or potential. The selectively self-deposited coating results from the high surface alkalinity of Mg. The ‘electroless’ E-coating pre-film can offer adequate corrosion protection for Mg alloys. The stability of the film can be further improved significantly after curing. The coating can be either a temporary or permanent layer. It may also be used to pre-treat a Mg alloy surface for a normal E-coating or powder coating. Such a simple dipping step can even seal porous phosphating or anodizing coatings on Mg alloys.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : K. Azumi,H.H. Elsentriecy,J. Tang
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Plating on Mg alloys has proved difficult due to their high susceptibility to the degradation reactions such as galvanic corrosion in the plating processes. In this chapter, surface conditioning, activation, electroless- or electroplating methods are discussed from viewpoints of corrosion engineering. Degradation reactions of the Mg substrate in each plating stage are considered to figure out how to suppress degradation of substrate and to achieve uniform deposition of a plating layer. Building up an interface between the substrate and the plating layer is also an important subject to establish enough adhesion strength of the plating layer and low defect density to prohibit corrosion progress of the substrate. Al coating plating on Mg alloys electrodeposited from an ionic liquid bath is also introduced to provide coatings with less-galvanic coupling property with a less-noble Mg substrate.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : S.A. Salman,M. Okido
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Anodizing is one of the most widely used surface treatments for magnesium and its alloys. In this electrolytic oxidation process, the surface of a metal is converted to an anodic oxide/hydroxide film with desirable protective, decorative or functional properties. This chapter describes the fundamentals of anodizing treatment, with an emphasis on the difference between magnesium anodizing and aluminum anodizing. The chapter then discusses the most widely used commercial anodic treatments and describes how the treatment conditions affect the corrosion resistance and the physical and mechanical properties of the anodic coating that forms on magnesium alloys. A critical review of recent patents and advances in the anodizing of magnesium is given. After reviewing the literature, the chapter explains how surface treatment can lead to more widespread use of magnesium alloys in a range of industrial applications.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : B.L. Jiang,Y.F. Ge
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Micro-arc oxidation (MAO) is a novel and attractive surface engineering process for magnesium (Mg) alloys. In an electrolytic bath with high electric energy, the surface of a magnesium alloy can be converted into a dense and hard ceramic oxide coating. The MAO process can be used in diverse applications as a corrosion control technique. Due to its simplified pre-treatment, superior corrosion resistance performance and environmentally safe coating process, MAO technology has emerged as an important alternative to anodizing techniques in certain areas. This chapter presents a review of MAO techniques for Mg alloys from the scientific, technological and application points of view.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : G.-L. Song,Z. Xu
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Corrosion is a surface degradation process determined by an alloy’s surface state, composition and microstructure. This chapter presents an overview of surface processing and alloying techniques that can improve the corrosion resistance of Mg alloys. It is found that some surface engineering processes can significantly change the surface state, composition and microstructure of Mg alloys. For example, surface mechanical and chemical cleaning can effectively remove surface contaminations; burnishing can modify the surface layer’s microstructure including grain size and grain orientation; surface alloying can produce a metallic layer on top of the Mg alloy base material. All these surface engineering processes lead to enhanced corrosion resistance of Mg alloys without affecting their bulk properties.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : J. Meng,W. Sun,Z. Tian,X. Qiu,D. Zhang
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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In magnesium alloys, the rare-earth (RE) elements first react with the impurities in the alloy, then with alloying elements, and finally form an intermetallic compound with magnesium. Therefore, RE elements play the key role in removing impurity and purifying the matrix in Mg alloys so as to enhance the corrosion resistance. The RE elements have a lower electrode potential resulting in a decrease in the electrode potential of the intermetallic compound in which they participate. The reaction results lead to reduced electrode potential difference between the matrix and second phase. It will play an important role in reducing galvanic corrosion.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : J. Dutta Majumdar,I. Manna
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Magnesium and its alloys are promising materials for automotive, aerospace and bio-implant applications due to low density (1.81g/cm3), very low elastic modulus (45GPa) and high tensile yield strength (200MPa). However, they corrode too quickly in aggressive environments and possess poor wear resistance. Wear and corrosion are essentially surface dependent degradation which may be improved by suitable modification of surface microstructure and composition. Laser as a source of coherent and monochromatic radiation may be applied for tailoring the surface microstructure and composition. In the present contribution, a detailed overview of laser surface engineering of magnesium-based alloys is presented. Finally, the future scope of application of laser surface engineering of magnesium-based alloys is presented with examples.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : W.-T. Tsai,I.-W. Sun
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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To improve the corrosion resistance of magnesium (Mg) alloys, surface modification is applied in an attempt to produce a corrosion resistant barrier. In this chapter, a new method to deposit aluminum (Al) film on a Mg alloy surface is demonstrated. Electrodeposition of Al on AZ91D Mg alloy, using an acidic aluminum chloride–1-ethyl-3-methyl-imidazolium chloride ionic liquid (AlCl3–EMIC), has been shown to be feasible. The existence of Al coating can cause a substantial increase in corrosion resistance, reducing the susceptibility of Mg alloy to aqueous corrosion. The results of electrochemical impedance spectroscopy show that Al coating leads to an increase in the polarization resistance of a bare Mg alloy by one order of magnitude in 3.5wt% NaCl solution. Furthermore, the potentiodynamic polarization results show that Al-coated Mg alloy can be passivated, and a wider passive region with a lower passive current density can be obtained if the Al is electrodeposited at a lower applied current or a low cathodic overpotential. The passivity of the co-deposited Al/Zn film is slightly inferior to that of the pure Al coating.

Corrosion prevention of magnesium alloys

Corrosion prevention of magnesium alloys
Author : V.K. Champagne,B. Gabriel,J. Villafuerte
Publisher : Elsevier Inc. Chapters
Release Date : 2013-02-22
Category : Technology & Engineering
Total pages :582
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Magnesium alloys are widely used in aircraft and automotive components because of their inherent light weight compared to other engineering metals. However, premature corrosion is one of the challenges associated with magnesium. In the aerospace industry, many expensive castings cannot be reclaimed adequately because current methods are often inappropriate due to excessive porosity, oxidation and thermal damage. Cold spray is a solid-state coating process that uses a supersonic gas jet to accelerate small particles against a substrate to produce metal bonding by rapid plastic deformation of the impacting particles. Significantly, magnesium components can be repaired, restored and protected by cold spray deposition of pure aluminum which has thus already been specified by some aerospace users as a standard technique for magnesium repair. In this chapter, the state of the art of commercial cold spray technologies for magnesium repair will be discussed, as well as their advantages and limitations compared to traditional thermal processes.