Colored stainless steel sheets are stainless steel sheets that have been treated to change their color without compromising the corrosion resistance that’s characteristic of stainless steel. The color is not a coating, paint, or dye, but rather a layer of color that is integrated with the surface of the metal and thus cannot chip or flake off.
There are two common methods of producing colored stainless steel sheets:
- Chemical Coloring (Immersing Method): This method involves immersing the stainless steel sheet in a heated bath of chemicals. The sheet is then subjected to an electric current which stimulates a reaction between the chemicals and the metal surface, forming a layer of chromium oxide that changes the color of the steel. The color achieved is dependent on the thickness of the oxide layer. This process, known as electrochemical coloring or INCO coloring, doesn’t use any pigments or dyes, and the resulting color is extremely durable.
- PVD (Physical Vapor Deposition) Coloring: This process involves vaporizing a metal (like titanium, chromium, or zirconium) and applying it to the stainless steel surface in a vacuum. The vaporized metal reacts with specific gases to form a thin, extremely hard coating on the steel surface. This coating, often just a few microns thick, changes the color of the stainless steel and can also enhance its corrosion and scratch resistance.