Anodizing is a technique used to change the exterior of a metal. A change in the surface topography and crystal structure may occur, as well as an increase in corrosion resistance when anodizing. The process of anodizing is often used to protect titanium and aluminum from abrasion and corrosion. It also allows metals to be dyed in various colors.
Anodizing is an important industrial process; anodized metals are popular throughout industry and commerce, including the computer product context. They are valued for their corrosion resistant properties and for their appearance. They can be used in decorative paneling, as housing for electronics like computers, as furniture components and in many other applications. Types of anodizing include titanium anodizing, niobium anodizing and aluminum anodizing.
Aluminum anodizing is the most popular because the chemical structure of aluminum alloys are strengthened by an anodizing treatment rather then deteriorated as some metals are. Iron, for example, rusts when bathed or painted with the acid treatment. The essence of this acid treatment varies, but three common styles are the chromic acid anodization, sulfuric acid anodization and hard anodization.
All three processes involve immersing a metal into a vat of chromic or sulfuric acid, and then using an electric current to change the chemical structure on the surface of the metal. With certain metals like aluminum and titanium, the oily and corrosive substances strengthen and harden the metals, making them weatherproof and also improving them aesthetically.
Color anodizing, clear anodizing and custom anodizing are a few examples of other anodizing processes also offered by anodizing operations. Clear anodizing is the natural result of a sulfuric acid treatment, although it can be turned into a color anodization because the pore size after anodizing is larger and soaks up color better.
Custom anodizing is available for consumers that require specific levels of hardness, thickness or color. This is when the less well known anodizing styles are employed, smaller scale processes that offer more control and precision. Painting rather then submerging the metal in organic, citric or boric acids is a variation often used by custom anodizers. The anodizing process, which literally is changing the chemical structure of a metal, is not always environmentally friendly.
Certain types of anodizing emit toxic fumes into the atmosphere that can be detrimental to the health of the planet as well as humans in the area. Thankfully, there are enough safe acids that can be utilized that the industry is not suffering, and there are organizations that regulate the process to ensure safety.