Normal Anodizing/Type II Anodizing :

Normal acid Anodizing, often called “Type II, Class 1 & 2 anodizing” as denoted by MIL spec 8625, is an electro-chemical process that creates a controlled oxide film on the surface of aluminum. This is a standard specification used for aerospace,military and defense industry Sulfuric acid anodizing is a process that provides a conversion on aluminum which changes the surface of the material to a naturally occurring aluminum oxide. The oxide build up changes the surface of the aluminum which then provides greater abrasion resistance as well as increased corrosion protection. The finish will not only build up the aluminum oxide on the surface. Other than a clear anodize this coating may also be dyed in various colors. The typical industry colors include black, clear, green, gold, red, and blue. The less alloying elements in the aluminium, the result will be better for dying the anodic layer.One of the interesting property of the aluminum oxide is that it is a great electrical insulator.