Copyright 2009 Eastern Plating Company Website Design by Graphical Media Services What Is Anodize? There are many metals that are structurally weakened by the oxidation process, aluminum is not one of these metals. Aluminum surfaces can be made stronger and more durable through a process called 'anodizing'. Anodizing involves placing a sheet of aluminum into a chemical acid bath. The sheet of aluminum becomes the positive anode of a chemical battery and the acid bath becomes the negative. An electric current passes through the acid, causing the surface of the aluminum to oxidize  (rust). The oxidized aluminum forms a strong coating as it replaces the original aluminum on the surface. The result is an extremely hard substance called anodized aluminum. Anodized aluminum can be nearly as hard as diamond under the right anodizing process. Many modern buildings use anodized aluminum in places where the metal framework is exposed to the elements. Anodized aluminum is also a popular material for making high-end cookware such as frying pans and pots. Heat is distributed evenly across anodized aluminum, and the process of anodizing provides a naturally protective finish. It is possible to use another electroplating process to make anodized aluminum look like copper or brass or other metals. Special dyes can also be used to color the anodized aluminum for decorative uses. Because of its strength and durability, anodized aluminum is also used in a number of other applications. Many of the satellites circling the Earth are protected from space debris by layers of anodized aluminum. The automobile industry relies heavily on anodized aluminum for trims and protective housings for exposed parts. Furniture designers often use anodized aluminum as the framework for outdoor pieces as well as the base metal for lamps and other decorative items. Modern home appliances and computer systems may utilize anodized aluminum as protective housing. Eastern Plating Company anodizes to all three types of anodization specified by MIL-A-8625. This includes Types I, II, and III (hardcoat). Type I - Chromic Acid Anodize - Type 1 is anodizing that uses a chromic acid based chemical bath. Used mostly for aerospace and Defense Department requirements where a thin coating and a high level of corrosion resistance is desired. It is also used as an excellent primer for paint and other top coats. Type II - Sulfuric Acid Anodize - Type II is anodizing that uses a sulfuric acid based chemical bath. Used for general and commercial anodizing of aluminum, Type 2 is widely used for everything from toys to sporting equipment to computer hardware. The list is almost endless. Type 2 can be colored in virtually every color of the rainbow. Type III - Sulfuric Acid Anodize (Hardcoat) - Also called Hard Coat anodizing, Type III anodizing is used wherever a super hard surface is required. Type 3 is used in military equipment and weapons, scratch resistant aluminum cookware, commercial pizza pans, sporting goods, bearing surfaces to name just a few. Type III is not usually colored or dyed. Darker or lighter shades of grey to black are achieved by altering temperature, voltage and bath compositions. Anodize USEFUL AND INFORMATIVE LINKS www.astm.org - Search and purchase ASTM Specifications www.sae.org - Search and purchase AMS Specifications. www.finishing.com - Finishing information and forums assist.daps.dla.mil/quicksearch - Search and download Military Specifications. www.anodizing.org - find valuable information about the metal finishing process of aluminum anodizing