Phosphorylation and Chromate Passivation
Surface surface treatment is a process of changing or improving the physical, chemical and/or mechanical properties of the surface layer on a substrate. In the most general definition, the surface treatment process is used to enhance or change the substrate surface so as to form a protective coating or improve adhesion or wettability or prevent corrosion. There are several methods used today to extend the life of a substrate. Examples of applied surface treatments include anodization, alodization, galvanization, phosphorylation, passivation and chromate passivation.
In this paper, we are going to discuss the process of phosphorylation and chromate passivation. Phosphorylation and chromate passivation are surface treatments used to increase the corrosion resistance of metal substrates. They can also be used for aesthetic purposes.
Phosphorylation is a surface treatment process that uses a phosphoric acid-based electrolyte to create an oxide and phosphate layer on the substrate. The oxide layer provides a barrier and the phosphate layer helps to increase adhesion between the substrate and an organic coating. The oxide and phosphate layers resist corrosion, provide a good key for paint, and can reduce the effects of electrochemical reactions.
Chromate passivation is a chemical surface treatment that uses a chromic acid-based solution to create a coating on top of the existing oxide and phosphate layers created by the phosphorylation process. The chromate coating is then rinsed and allowed to dry. This coating helps to further protect the substrate and create an aesthetically pleasing finish.
When both the phosphorylation and chromate passivation processes are used together, the substrate is further protected against corrosion. The combined process helps to create a barrier against any environmental elements and also increases the adhesion of the substrate to an organic coating.
In some cases, the combined process of phosphorylation and chromate passivation can be applied without the need for any additional primers or finishes. In other cases, the phosphorylation and chromate passivation processes should be used with a primer and/or finish for added protection and aesthetic purposes.
When applied together, phosphorylation and chromate passivation can help to increase the life and overall performance of a substrate. The process not only protects against corrosion, but also helps to increase the adhesion of a substrate to an organic coating. This helps to further protect the substrate and improves the appearance of the finished product.
Overall, phosphorylation and chromate passivation are two effective processes used to improve the surface of a substrate. By applying both processes together, one can increase the substrate’s resistance to corrosion and also achieve an aesthetically pleasing finish. The combined processes help to create a barrier against any environmental elements and also provide an increased adhesion for organic coatings.
