Corrosion Of Magnesium Alloys

This book makes it easy for you to find what effect environment has on the corrosion of metals and alloys. However, this volume offers information on additional environments including concrete, soil, groundwater, distilled water, sodium acetate and more. ThereAs also updated and expanded coverage of previously discussed environments as well as information on environments which deal with the dairy, food, brewing, aerospace, petrochemical and building industries. The environments are listed alphabetically. Each listing includes a general description of the conditions, a comment on the corrosion characteristics of various alloys in such a situation, a bibliography of recent articles specific to the environment, tables consolidating and comparing corrosion rates at various temperatures and concentrations for various alloys, and graphical information. Also included are summaries on the general corrosion characteristics of major metals and alloys.

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.

Classical magnesium alloys are a combination of aluminium, magnesium, manganese and zinc. Magnesium combined with lithium forms ultralight alloys that have many uses. Since it is a reasonable material, it offers great possibilities and is constantly tested at various angles of applications and properties. Magnesium, previously used for military purposes, seems to fit perfectly to the requirements of the currently prevailing technology. Low density with appropriate mechanical properties (strength, high operating temperature), good foundry properties (high castability and low shrinkage), vibration damping ability and cost-effectiveness of recycling seem to be an ideal response to market needs. All things considered, magnesium alloys are the perfect material used in various industries starting from the automotive industry, through sport, electronics up to the space industry and defence. This book is written by experts in various areas of magnesium science and technology. It gives a general idea of modern advancements in theory and practical purposes of magnesium alloys. The book reports fundamental aspects of corrosion types and details about magnesium alloys designed to work in elevated temperatures and superplastic behaviour. Fundamentals, broad experience, theory as well as complex technological aspects make this work helpful for engineers and scientists from all over the world.

Magnesium is the lightest of all the metals and the sixth most abundant on Earth. Magnesium is ductile and the most machinable of all the metals. Magnesium alloy developments have traditionally been driven by requirements for lightweight materials to operate under increasingly demanding conditions (magnesium alloy castings, wrought products, powder metallurgy components, office equipment, nuclear applications, flares, sacrificial anodes for the protection of other metals, flash photography and tools). The biggest potential market for magnesium alloys is in the automotive industry. In recent years new magnesium alloys have demonstrated a superior corrosion resistance for aerospace and specialty applications. Considering the information above, special issues on magnesium alloys are exposed in this book: casting technology; surface modification of some special Mg alloys; protective carbon coatings on magnesium alloys; fatigue cracking behaviors of cast magnesium alloys and also, magnesium alloys biocompatibility as degradable implant materials.

This memorandum deals with the corrosion protection of magnesium and magnesium alloys. The corrosion resistance of these alloys in many natural environments, while not as good as that of copper, nickel, stainless steel, and aluminum, is in the same range as that of the iron and plain carbon steels. Some type of additional corrosion protection is often necessary and, as with steel, the protective measures usually involve some type of coating system and/or surface treatments. Also, magnesium can suffer accelerated attack when coupled, in the presence of a conductive electrolyte, to most metals below it in the galvanic series. This galvanic effect complicates the problem of corrosion protection. A number of coating systems have been proposed and used satisfactorily. Depending upon the application, these coating systems include the use of conversion coatings, organic coatings, metallic coatings, and others. In addition, special designs can be employed to improve the over-all corrosion resistance of the systems. This memorandum describes many of the coating systems and design methods which are used to reduce corrosive attack on both galvanically coupled and uncoupled magnesium assembliesd (Author).

This book covers fundamentals and recent advancements on conversion coatings for magnesium and its alloys. The contents are presented in two sections, respectively dealing with chemical and electrochemical conversion coatings. The chemical conversion coating section is further subdivided into inorganic conversion coatings, organic conversion coatings and advanced approaches/coatings. The section on electrochemical conversion coatings spans from fundamentals to state-of-the-art progress on electrochemical anodization and plasma electrolytic oxidation of magnesium and its alloys.

Magnesium and magnesium alloys provide unique properties for engineering applications. Magnesium alloys are popular as a structural material because of their combination of light weight and strength. They are desirable for portable tools, appliances, electronic devices, airplanes, space vehicles, and land transportation. This book is written for engineers, scientists, teachers, and students engaged in the design process of material selection and material elimination. While focused on mechanical properties for structural design, the physical properties that are germane to corrosion behavior and electrical applications are represented. Two-thirds of the book is devoted to datasheets for individual alloys which provide a handy quick reference to specific properties and performance. The remainder of the book addresses topics common to all magnesium alloys such as the alloy designation system and product forms. Casting alloys and wrought alloys are compared. The alloy performance at elevated temperature is presented, as are fatigue properties. Finally, a summary of the corrosion behavior of selected alloys is discussed along with how these corrosion mechanisms can be applied for beneficial results.

Magnesium alloys with their unique physical and chemical properties are important candidates for many modern engineering applications. Their density, being the lowest of all structural metals, makes them the primary choice in global attempts aimed at reducing the weight of transportation vehicles. However, magnesium also creates challenges at certain stages of raw alloy melting, fabrication of net-shape components and their service. The first one is caused by very high affinity of magnesium to oxygen, which requires protective atmospheres increasing manufacturing cost and heavily contributing to greenhouse gas emissions. The second challenge relates to very high corrosivity of liquid magnesium towards materials it contacts. This imposes restrictions on the selection of materials used to contain, transfer or process molten magnesium during manufacturing operations. A mixture of unique benefits and serious challenges of magnesium alloys in solid and liquid states described here makes the book very useful for a broad audience of scientists and engineers from academia and industry.