It is a no-brainer — aluminium is one of the most widely used metals in the industrial world. It offers a unique blend of important properties that make it a suitable choice of material for use in multiple industrial applications including building construction, automotive, aeronautics, transportation, packaging, energy distribution, and so on. Aluminium is a lightweight, corrosion-resistant metal whose strength, durability and aesthetic qualities can be improved by applying a surface finish onto the substrate metal. There are various types of finishes that can be used to enhance aluminium products. The finish-type you select for your aluminium is extremely important and typically depends on the intended use of the metal.
Read on below to learn about some of the main types of finishes available for aluminium.
1. Mechanical finishes
Generally speaking, mechanical finishes for aluminium can be grouped into two broad categories: (1) processes which clean or etch metal by abrasion, or (2) processes which improve the texture of the metal by mechanical force. Aluminium can be blasted, grinded, buffed, embossed, polished, or sanded. These surface treatments can enhance the surface quality or prepare the metal for other decorating finishes. For example, high finish polishing can be done to achieve a mirror finish in preparation for a bright anodising finish. In the same vein, cast aluminium components can be shot blasted to rid of cast skin and enhance the appearance of the components.
2. Chemical finishes
As the name implies, chemical finishes are achieved by relying on chemical processes. Here, aluminium can be cleaned, etched, milled, electrochemically plated, brightened, etc. Chemical surface treatments can be used as a pre-treatment prior to application of other coating systems or used to achieve a spectacular finish without any further finishing. Chemical brightening, for example, is used to remove surface texture to desired depth and give a mirror finish. Chemical cleaning, on the other hand, is used as a pre-treatment designed to remove surface impurities that may be inhibitive to effective application of final finishes.
Aluminium is a highly reactive metal that readily reacts with the oxygen in the air to form an inert protective layer known as aluminium oxide. Anodising is used to make the layer of aluminium oxide thicker so as to provide better protection for the substrate. It is achieved by dipping the metal in an electrolyte — often aqueous sulphuric acid. Anodised finishes include hard anodising, decorative anodising and electrolytic polishing, depending on the intended use of the aluminium.
Aside from the above discussed finishes, aluminium can also be painted and powder-coated. To find out the right finish-type for your aluminium, contact an aluminium fabrication expert.