TAILIEUCHUNG - CHEMISTRY, ELECTROCHEMISTRY, AND ELECTROCHEMICAL APPLICATIONS
Aluminum is the most abundant metallic element, making up about 8% by weight of the Earth’s crust. It is a silverywhite metal and belongs to group III of the periodic table. Its atomic number is 13 and atomic weight 54. Pure aluminum is soft and ductile. | CHEMISTRY ELECTROCHEMISTRY AND ELECTROCHEMICAL APPLICATIONS Contents Aluminum Carbon Iron Hydrogen Lead Lithium Manganese Nickel Oxygen Platinum Group Elements Silver Zinc Aluminum Q Li JO Jensen and NJ Bjerrum Technical University of Denmark Lyngby Denmark 2009 Elsevier . All rights reserved. Introduction Aluminum is the most abundant metallic element making up about 8 by weight of the Earth s crust. It is a silvery-white metal and belongs to group III of the periodic table. Its atomic number is 13 and atomic weight 54. Pure aluminum is soft and ductile. However it can be alloyed with small amounts of copper magnesium and silicon to increase its strength and impart a number of useful properties such as high strength good ductility and low density. The most common aluminum alloy A6061 for example contains copper magnesium silicon zinc and iron and is widely used as a vital structural component in aerospace automotive railroad and other industrial applications. Chemically aluminum is very reactive. Whenever a freshly created aluminum surface is exposed to air or water at room temperature an oxide film forms immediately and grows to a thickness of about 5 nm in air and to a somewhat greater thickness in water. This oxide layer is impervious and adherent to the metal surface protecting aluminum from further corrosion. It is this oxide layer that makes aluminum remarkable for its corrosion and wear resistance. Aluminum surface coatings onto other metallic substrates are a well-known technology for corrosion protection. Anodizing an electrolytic passivation process to increase the thickness of the natural oxide layer on the surface of metal parts forms an important part of aluminum electrochemistry and offers better use of the oxide layer. The electrochemically prepared oxide layers can be either porous or barrier type the former providing corrosion resistance and allowing for coloring the surface with organic dyes pigment .
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