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What is Anodizing? Anodizing is an electrochemical process, that converts the aluminium surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Anodising also increases the wear resistant of the metal and produces a much better surface for the application of primers and paints. Anodising is often followed by dying, to produce an attractive, colourful finish. Anodised layers are non-conductive and provide improved adhesion for other finishes. An anodised surface is entirely integrated with the surface of the metal, it will not chip or peal away.
Anodising is a process through which a metal such as aluminium, receives a corrosion resistant, oxide finish (anodic finish). This is an oxide layer (aluminium oxide) created through electrolysis.
The metal, aluminium in this case, acts as the anode (positive electrode), as it is positively charged. It is submerged in a solution of sulphuric acid, sodium sulphate and water. Lead plates act as the cathode (negative electrode) and when electricity is allowed to flow, oxygen ions are released from the electrolyte. They combine with aluminium atoms at the surface of the anode, creating a thin oxide layer.
|Anodised finishes can be found all around us. It is used as a finish on some of the worlds must famous high buildings, including the Sears Tower in Chicago. It is often found as a finish on interiors, such as a aluminium stair cases and escalators. A recent medical innovation, is in the production of anodised titanium dental implants and other medical implants. MP3 players, mobile phones and many other electronic gadgets have an anodised finish, that is also colourfully dyed. Scientific instruments are often anodised.|
|SOME METALS THAT CAN BE ANODISED|
|ALUMINIUM - TITANIUM - MAGNESIUM - ZINC - TANTALUM - NIOBIUM|
|Dyes are often added as part of the anodising process. Organic acids are mixed with the electrolyte and they are selected according to the final colour required. An alternative method is to apply colour after the anodising process, using solvent based dyes, that are adsorbed by the porous anodise surface.|
|ANODISED FINISH - COLOURS / SHADES - SAMPLE PRODUCTS|
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