20
July 2015
The most popular coloring methods of Stainless Steel
Stainless steel is nowadays a very popular material. Its corrosion resistance, its high tolerance in time and environmental circumstances along with its aesthetic quality make inox a unique material. There were times that the natural look of the material could not meet the aesthetic demands of the project and this is how the idea of painted inox came up, where the creator could combine the mechanic features of the material with the appropriate coloration. This brought the construction of high-aesthetic buildings with better structure around the globe.
Painting
The anti-corrosion features of stainless steel are well known therefore painting inox is mostly for aesthetic purposes unlike other metals. To apply paint correctly on an inox product its surface must be well prepared so that we do not face any unpleasant effects like pealing or cracking of the paint that may cause corrosion. Therefore, pickling with good rinsing afterwards or abrasion for smaller surfaces is suggested in order to prepare the surface the best you can. This procedure needs to be thorough so that all traces of grease, oil and foreign elements. It is also important to remove passivated surfaces so that the paint is better absorbed. A very popular preparation procedure for stainless steel painting is sand-blasting as it can adjust how hard or soft the metal is. Those who choose to paint stainless steel will have to keep in mind that the painting will eventually fail as the metal is more fond to environmental circumstances than to chemical paint.
Metallic coating
Metallic coating was mostly used in roof-tops and drainage pipe systems. Nowadays it is also applied to exterior wall claddings. It is very common for stainless steel to paint it with one layer of tin to improve the surface for the coating. In that case it just needs a primer (suggested by the fabricator) before the coating and effectively material passivation is not required. There is also the coating with copper with galvanization. Another yet very important advantage of metallic coating is that if the surface gets scratched or injured it does not affect the anti-corrosion properties of the material.
Electrochemical painting
As one of the oldest stainless steel painting methods, the electrochemical painting has moved on many stages to end being one of the most popular yet pricy methods. The aesthetic result is uniform or iridescent and proportional to the process we conduct. The light and the point of view from which we look at the coloring or the spot where the metal has a leaning angle can give many color shadings. Electrochemical painting is a irreversible method that must be performed in final products and you cannot weld, curve of bend the surface as those may cause permanent damage on the color. It is also important to point out that if the color is damaged there is a high risk of metal corrosion and its life expectancy is shorter.
PVD or Sputtering
The Physical Vapor Deposition coating or sputtered color is a series of process methods during which thin layers are created with particles on the metal surface. It is quite popular as the color variety is wide, the aesthetic result is satisfying and the surface is reinforced against corrosion, friction and with endurance. It is widely used in industry and for home products. The procedure is conducted in sealed spaces and in inert atmosphere. An inert gas is needed in order for the vapor particles to lay on the final product’s surface and the gas is usually argon. The original form of the material that is applied on the material starts vapor and its particles fall on the metal, creating tolerant in time and corrosion thin layers on the surface of the substrate. There are many ways to “melt” and vapor the cover product like high power catholic arc, laser, high vapor pressure and plasma discharge bombardment (also known as sputtering). The thin layer created is ceramic not metallic and the texture of the substrate is usually visible. The PVD coating can be ruined if it is severely injured; therefore it is absolutely necessary to apply it on final products that do not need any further processing.
Information source: www.euro-inox.org