Aluminum Anodizing Types and Terms

  • Anodizing is a technique used to coat the exterior of a metal with a protective film.
  • Black anodizing is a process through which the surface of an anodized coated with a protective black dye.
  • Bright dip anodizing refers to the pretreatment step before anodizing, which takes place in a bath of acids and creates a bright, shiny finish.
  • Chromate conversions is a process that provides corrosion resistance and makes the aluminum surface electrically conductive. It also provides a superior surface condition for the application of paints, powder coats and adhesives.
  • Clear anodizing preoxidizes the aluminum surface for a clear, uniform finish.
  • Color anodizing is when a colored coat is applied to the exterior of a metal.
  • Conventional/Sulfuric anodizing provides a thin coating of aluminum oxide that is tightly bonded to the surface of the aluminum. This method offers corrosion resistance and aesthetic appeal, as well as makes the aluminum surface electrically non-conductive.
  • Hard coat anodizing is a variant of anodizing. It produces similar results to standard anodized surfaces, but the thicker and denser hard anodic film limits the coloring results to dark tones.
  • Impregnation is the filling of internal cracks, voids and corroded pockets, which would otherwise cause castings, forgings and powdered metal parts to leak.
  • Titanium anodizing is used most often in the jewelry segment of the industry, as it has less occurrence of skin allergy than any other metals.

Abrasion - The process of using friction to grind and wear away at a surface.
 
Activation - Changing a metal surface into a chemically-active state.
 
Alloy - A substance with metallic properties composed of two or more chemical elements. At least one element must be metal.
 
Alumina - An intermediate step in the production of aluminum from bauxite.
 
Anodizing Sheet - A sheet that has suitable metallurgical characteristics and surface quality for the development of protective and decorative films by anodic oxidation processes.
 
Bath - The chemical environment in which the anodizing takes place.
 
Brazing - Joining metals together by flowing a layer of molten filler metal between them.
 
Chemical Film - The application of chromate conversion coating on aluminum.
 
Corrosion - The gradual chemical or electrochemical wearing of a surface. Also, this is the deterioration due to environmental forces.
 
Cryolite - A white mineral used in making aluminum
 
Deburring - The removal of burrs, sharp edges and fins by mechanical, chemical or electrochemical means.
 
Edging - Dressing metal edges by rolling, filling and drawing.
 
Hardener - An alloy of aluminum and at least one other metal that is used to make additions to molten aluminum.
 
Impurities - Undesirable elements in aluminum compounds.
 
Inhibitor - A substance used to reduce the rate of a chemical or electrochemical reaction, commonly corrosion or pickling. 
 
Melting Point - The minimum temperature at which a metal will melt.
 
Passivation - Changing a chemically active metal into a passive state.
 
Plating - The process of laying a thin coat of metal on another.
 
Pores - Microscopic openings in an anodized surface, leading to a microscopic tube. Although porous, the anodized surface is very dense and hard.
 
Rack - The electrically-conductive device used to hold the parts to be anodized as they are lowered into the bath. Racks are made in different sizes, types and shapes to hold the large variety of parts and products encountered in anodizing.
 
Refined Aluminum - Aluminum that is in a very pure state.
 
Smelt - Fusing or melting ore in order to extract or refine the metal it contains.
 
Striation - Longitudinal lines that are not uniform, caused by uneven coating.
 
Ultimate Strength - The maximum stress a material can withstand.