Untreated aluminium, referred to as mill finish aluminium, is extremely vulnerable to corrosion and discolouration, rendering it unsuitable for use in the construction industry unless it has been treated. The most popular treatment in the last forty years has been powder coating, although anodised coating of aluminium has been in use for almost twice as long and has considerable advantages over its rival.
Powder coated aluminium requires the mill finish product to undergo various treatments before coating takes place and essentially remains as painted aluminium. Anodising is an electrochemical procedure that prompts a reaction between the aluminium and the other components used in the treatment to create a very different form of the metal rather than receiving a coating that merely paints the surface. Anodised aluminium has a lifetime guarantee because it cannot corrode or fade. Additional qualities of superior strength and durability have made it the preferred choice in the construction of satellites and computer hardware. It has also become a favourite material amongst architects who value its intense metallic sheen when designing contemporary buildings, using it for many functions including walls, window frames, staircases and lifts.
The Anodising Process
To create an anodised aluminium, the mill finish version is treated through a technical process to transform it into an entirely different form of aluminium. To begin with, mill finish aluminium is placed in an acid electrolyte tank which then has an electric current passed through it. The chemical changes that create anodised aluminium occur when the current flows from cathode to anode, which are both determined by the current itself. The cathode is negatively charged while the anode is positive and as a result, the cathode attracts the anode. The acid electrolyte tank becomes the negative cathode, the aluminium is the positive anode. The chemical attraction between these two elements causes a reaction between the aluminium and oxygen to form aluminium oxide which creates the new anodised metal. The strength of the anodised aluminium and the depth of colour increases in direct relation to the length of time the process is allowed to continue.
Professional Anodising Skills
Anodised aluminium is available in an extensive range of colours with an intense metallic sheen, which are achieved through different applications of electro-colouring. The anodised coating of aluminium is a complex electrochemical process that requires the expertise of professional anodising companies such as Edmo whose products offer superior qualities of strength, colour and durability.