The electro-polishing process is an advanced electrochemical technique used to improve metal surfaces, especially stainless steel. This process is suitable for both parts and sheets, as it effectively removes microscopic surface irregularities and imperfections.

The result is a smoother surface with increased reflectivity. The level of smoothness and reflectivity achieved depends on the initial roughness of the material. However, it is important to note that electro-polishing cannot produce a mirror finish like mechanical polishing methods. Non-metallic surface contaminants are removed during the process, and the smoother surfaces are more corrosion-resistant since they are easier to clean and do not trap contaminants.

Electrolytic Colored Finishes

Stainless steel can be colored using electrolytic processes. In this method, a thin layer of neutral chromium oxide is formed on the surface, and depending on the immersion time in the acid solution, it can result in various colors such as bronze, gold, red, purple, blue, and green. These colors emerge as the oxide layer thickness increases from 0.02 to 0.36 microns. One of the benefits of this process is that the color does not fade under UV light since no pigments are used. The final appearance of the surface depends on the original finish of the steel. For example, if the surface is matte, the final color will also appear matte, and if the surface is polished, the final color will be highly reflective.

The color produced through this process is permanent and does not require repainting. However, the surface must be carefully maintained, as any damage to the oxide layer cannot be repaired, and the steel cannot be welded without damaging the color. When cleaning these surfaces, it is essential to avoid using chloride-containing solutions or abrasive tools such as steel wool, as they can cause permanent damage to the oxide layer.

Textured and Colored Finishes

Another interesting technique for stainless steel coloring involves creating patterns on the surface. This process combines pattern embossing with coloring, producing aesthetically pleasing designs. After coloring, grinding can be used to remove the color from the raised sections, resulting in a surface with a mix of the natural stainless steel color and the applied color. Additionally, the raised areas become less sensitive to physical damage. This method not only enhances the product’s appearance but also increases the durability of the raised portions against impacts and scratches.