Before paint, the surface can be prepared with three different methods which are developed for aluminium and aluminium alloys in terms of surface treatment applications.
1- Aluminium acidic degreasing Rinsing two times Chromate Rinsing
2- Aluminium acidic degreasing Rinsing Nitric acid bath Rinsing Chromate Rinsing
3- Aluminium alkaline degreasing Rinsing Caustic bath Rinsing Nitric acid Rinsing Chromate Rinsing
It is possible to coat the aluminium based materials with yellow, green and transparent coloured chromate. Yellow chromate coats Cr+6, green and transparent chromates coats Cr+3. Coating weight can vary between 0,4-1,5 gr/m² according to application time and coating type. Drying temperature is recommended to be at 60º-80ºC for yellow chromate and 85º-90ºC for green and transparent chromate coatings. Coating is not wanted to be burnt while drying. Heating is used in alkaline degreasing and caustic baths for aluminium alkaline degreasing process. All other baths work at room temperature. Using the special additives developed for nitric acid and caustic baths increases the surface quality. It removes the problems related to the aluminium solution.