Anodising can produce a variety of colours and finishes to allow for increased aesthetic appeal and uniformity in a range of applications. DecoUltra AD anodising is available in clear (standard) anodised finishes, as well as black and bronze colours on request, with darker colours being achieved through increasing the hardness of the anodising process to 50 microns or higher using our DecoUltra ZD hard anodising technology. 

Dyeing Process

Prior to sealing the pores of anodised aluminium, it undergoes a dyeing process by being immersed in a bath of coloured dye. The dye permeates the pores and remains embedded in the anodised surface after sealing. Dyeing proves to be an effective method for imparting colour to anodized products. However, it is essential to recognize that the reproducibility of colours can vary, with certain hues exhibiting more consistent results both between and within batches. For instance, black dye yields minimal variation, whereas red and blue dyes may result in greater differences between batches or even among parts within the same batch. Notably, achieving white-coloured anodizing is unattainable due to the larger size of white dye particles, composed of titanium dioxide, which surpass the dimensions of the aluminium oxide pores.

Electrocolouring Process

The electrocolouring process entails immersing the anodized product in an electrolytic tin solution. This gives rise to an organic 'salt' that deposits at the base of the aluminium oxide pores and is subsequently sealed in. By adjusting the duration of immersion and the applied voltage, a diverse range of colours can be achieved. Maintaining consistency in colours necessitates precise control over the combination of time and voltage. Electrocolouring has the capability to produce an array of colours, spanning from red and blue to various shades of bronze. It is noteworthy that hard anodizing can undergo both dyeing and electrocolouring processes. However, as the anodic layer is darker than standard anodizing, it does impact the visual appearance of the coloured product.

Download our whitepaper to learn more about the benefits of anodising.