Pre-Treatments : Effective cleaning and preparation of components
Pre-treatment is a chemical process in which the surface of the component to be coated is cleaned and prepared for the coating operation. Our team select the appropriate chemical for the metal substrate dependant on size, customer specification and additional process requirements.
Our range of pre-treatments include:
A type of conversion coating that forms a complete film on the part surface, changing the chemical and physical nature of the metal surface. An iron oxide base is developed, followed by a metal phosphate topcoat. The treated metal surface will typically have a grey to blue iridescent finish, depending on the coating weight and the base metal.
In our iron phosphate process, the cleaning and coating are combined by the incorporation of a detergent surfactant into the iron phosphate solution. Parts treated with our Iron phosphate pre-treatment will typically achieve 300-400 hours of salt spray resistance (dependant on subsequent coating system).
Our Toran3 polymer system is supplied by Envirometal Technologies and works using Plaforization. *Plaforization is a unique and patented treatment for multi metal products which, when dipped or sprayed with fluids at ambient temperature, are degreased, phosphated/polymerised, protected and prepared, in one, single operation, for the immediate or future application of either powder or liquid paint.
Toran 3 does not contain phosphoric acid but works in a double-cure system with powder coating systems. Greases and oils on the metal are dissolved and chemically transformed to form part of the clear protective layer laid down on the product which is impervious to water and gives high adhesion for paint. Any dirt, dust or metal particles are washed from the product and then filtered out. Plaforization™ does not generate any waste for notifiable disposal. No sludge, no waste water, no VOC and so is one of our most environmentally friendly pre-treatment processes.*
Parts treated with our Toran3 pre-treatment will typically achieve 600-700 hours of salt spray resistance (dependant on subsequent coating system) with some tests achieving in excess of 1000 hours. *Source – www. envirometaltech.co.uk.
Our Oxsilan chemical is manufactured by Chemetall and is an eco-friendly and multi-metal pre-treatment process. **The Oxsilan® process is based on silanes that form aqueous solutions, through hydrolysis and condensation, polysiloxanes. During coating process, the reactive silanol groups can be chemically bonded to the metal as well as to the paint coating.
Heat treatment, e.g. following cathodic electropainting (CEP), further cross-links the polysiloxanes. This creates layers in the range of 100 nm. In combination with many paint systems, this is already sufficient to achieve the same degree of corrosion protection as with the ten times thicker zinc-phosphating layers, thereby reducing materials consumption and pre-treatment times and increasing productivity.**
Parts treated with our Oxsilan chemical will typically achieve a minimum of 1000 hours of salt spray resistance (dependant on subsequent coating system). **Source – www.chemetall.com
Another type of conversion coating, Zinc phosphate is a non-metallic, crystalline coating that chemically adheres to the substrate. Zinc phosphate coatings are extremely adherent, they provide a uniform coating with improved coating adhesion properties, better coating in recessed areas and better corrosion resistance and have been widely used in the automotive sector for many years. Unlike Iron Phosphate treatments, zinc phosphate is unable to clean and coat simultaneously and so our 8-stage zinc phosphate line includes cleaning, rinsing and conditioning stages.
We believe that correct chemical selection is an essential part of the coating process and our team will assess the most effective method to achieve our customer’s end result. If you’re not sure which one is best for you, please contact us for advice.
The performance of any coating is significantly influenced by its ability to adhere properly to the substrate material. As the first stage of the metal finishing process, surface preparation is an essential element to ensure subsequent coating success. Surface preparation methods are used to remove surface contaminants such as scale, rust, oxide edges caused by the manufacturing process together with existing coatings and we are able to offer a variety of both mechanical and chemical preparation methods that include those mentioned on the right.