Hard Anodising is a type of heat treating, which involves the application of anodic or cathodic coating on a ferrous or nonferrous metal item, and is used by companies like Poeton. It is achieved by passing an electric current through the article or area of interest, which generates heat on contact with the coating. Anodising also allows metals like aluminium to gain better performance in many different applications in the industrial sectors like aerospace, precision engineering, space and defence. It also helps metals attain better mechanical properties by reducing friction and preventing corrosion. Hard Anodising is often combined with other process steps for enhanced results.
The most common types of anodising used in the automotive industry are Type I and Type IV, which are respectively the slowest and the most effective types of hard anodising. For Type I anodising, an electric current is passed through the ferrous or nonferrous metal article under controlled pressure so that the colour change occurs at a particular wavelength. This is the most commonly used method in the aerospace industry, where this type of coating is used in components like aluminium airframes. Another type of this treatment utilises a different type of laser technology known as pulsed illumination, or Pulsed Light Anodising (PLA). For this process, a green beam of laser light is used against an aluminium alloy to induce the colour change.
The most popular colour change coatings are those that utilise both the anodic and cathodic properties of hard anodising. This is because it is easier to control the thickness of the colour through these properties, and it achieves a better overall finish with lesser maintenance costs. Other factors that affect the final colour of the metal that has been treated using this process include: the type of additives that are used in the anodisation process (i.e. the metal additive compounds that are using to promote the colour change), the thickness of the colour, the metallic properties of the base material that is used, and the properties of the anodic and cathodic beams of laser light that are used to carry out the treatment.