Anodising is a chemical process that leads to a rise in the oxide layer thickness on the surface of aluminium. In its natural state, the layer is highly thin. Since the layer is attached to a soft metal, it is prone to damage. The thicker layer protects the integrity of the aluminum underneath it.
The coating produced by anodising the metal is more proof against abrasion and corrosion. In a few cases, the oxide layer is permeable permitting the method to add colour. This gives the aluminium a protecting finish that is also ornamental.
Producers of appliances, automobile parts and sea equipment use this process. Architectural pieces including doors and windows are sometimes anodised. The process helps in producing lighting equipment, furniture and certain sporting goods.
Correct coating of a part needs preparation. A weak alkali solution washes away any grease or oil sticking the surface. Etching of the surface removes any heavy oxides that will meddle with the coating. The method of etching leaves insoluble material on the surface and requires submersion in a desmut solution to get rid of it. Water washes the part and completes the preparation process.
The next step is to dunk the part in an acid and water blend. The acid used depends upon the required coating. Organic acids work best for hard coatings while sulphuric acid is used for soft coatings that accept dye easily.
With the applying of direct current, the water breaks down and oxygen deposits form on the aluminum part. This forms the oxide film. When the anodic film is the required thickness, the processor takes away the part and rinses away the acids.
Three different techniques of coloring are used in this process. Full immersion in an inorganic pigment or organic dye will grant the film pores to absorb the colour. UV radiation has no effect on some inorganic pigments but just about all organic dyes will change color with lengthened exposure to UV rays.
Integral color involves processing the part and manipulating assorted parameters. The electrolyte composition, current density and temperature react with the metal's alloying elements to provide assorted colors. The intermetallic particles are colored and spread thru the film.
Electrolytic deposition is the third way to add colour. This is a technique where the anodic film base accepts deposits of oxide particles and stable metals. After sealing, the clear film locks in the specified color.
Clear or colored films are similarly efficacious in safeguarding the metal surface. When used for exterior architectural or structural applications the coating thickness ranges from 20 to 25 microns. This is also an appropriate range for sea applications. The film thickness could be as little as 10 microns for some environments.
Anodised metal is a good way to bolster the structural integrity. It also defends the part from abrasions, corrosion and exposure to the elements. It is widely used in the sea industry as it gives great protection against the cruel climate, which may cause damage to metal. The process is not employed in places where parts bend because the film can crack.
The coating produced by anodising the metal is more proof against abrasion and corrosion. In a few cases, the oxide layer is permeable permitting the method to add colour. This gives the aluminium a protecting finish that is also ornamental.
Producers of appliances, automobile parts and sea equipment use this process. Architectural pieces including doors and windows are sometimes anodised. The process helps in producing lighting equipment, furniture and certain sporting goods.
Correct coating of a part needs preparation. A weak alkali solution washes away any grease or oil sticking the surface. Etching of the surface removes any heavy oxides that will meddle with the coating. The method of etching leaves insoluble material on the surface and requires submersion in a desmut solution to get rid of it. Water washes the part and completes the preparation process.
The next step is to dunk the part in an acid and water blend. The acid used depends upon the required coating. Organic acids work best for hard coatings while sulphuric acid is used for soft coatings that accept dye easily.
With the applying of direct current, the water breaks down and oxygen deposits form on the aluminum part. This forms the oxide film. When the anodic film is the required thickness, the processor takes away the part and rinses away the acids.
Three different techniques of coloring are used in this process. Full immersion in an inorganic pigment or organic dye will grant the film pores to absorb the colour. UV radiation has no effect on some inorganic pigments but just about all organic dyes will change color with lengthened exposure to UV rays.
Integral color involves processing the part and manipulating assorted parameters. The electrolyte composition, current density and temperature react with the metal's alloying elements to provide assorted colors. The intermetallic particles are colored and spread thru the film.
Electrolytic deposition is the third way to add colour. This is a technique where the anodic film base accepts deposits of oxide particles and stable metals. After sealing, the clear film locks in the specified color.
Clear or colored films are similarly efficacious in safeguarding the metal surface. When used for exterior architectural or structural applications the coating thickness ranges from 20 to 25 microns. This is also an appropriate range for sea applications. The film thickness could be as little as 10 microns for some environments.
Anodised metal is a good way to bolster the structural integrity. It also defends the part from abrasions, corrosion and exposure to the elements. It is widely used in the sea industry as it gives great protection against the cruel climate, which may cause damage to metal. The process is not employed in places where parts bend because the film can crack.
About the Author:
Badger Anodising (Birmingham) L.T.D are a UK based anodising, metal finishing and metal polishing company. Alumimium extrusion gets passed to the company and they can then work their wizardry.
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