Passivation is a chemical treatment designed to protect the surface of ferrous materials such as steel and stainless steel from corrosion or rust, thereby improving their appearance, performance and cleanliness. The process involves immersing the machined metal parts in an acidic solution such as nitric acid or citric acid to remove iron from the surface, resulting in a smooth and polished surface.
Since passivation is not a coating process, there is no need for masking and no thickness added to the machined parts. The acidic solution removes traces of iron and rust from the surface of the parts and forms a protective film composed of chromium or nickel on the metal surface. Although nitric acid is the traditional passivating agent, citric acid solutions are widely used due to their shorter cycle times.
Passivated parts have excellent rust resistance and are ideal for outdoor applications. More importantly, passivation is a surface treatment method widely used in various industries, from the aerospace industry, which requires high-quality steel and tight dimensional tolerances, to the medical industry, which has extremely high requirements for product sterilization and service life.
However, passivation can increase part production time because these metal parts require pre-treatment prior to passivation, such as cleaning to remove debris, grease or other contaminants. While immersion is the most common passivation technique due to its fast cycle times and consistent performance, acid spray is also a more efficient option.(来源：UG学习堂小胥收徒)
MID focuses on high-precision parts manufacturing and services, providing one-stop solutions covering CNC precision machining, and has rich experience in diversified surface treatment processes. Including anodizing (multiple colors available), nickel/chrome electroplating, sandblasting polishing, passivation treatment and Teflon coating, etc., which can significantly improve the corrosion resistance, wear resistance and appearance texture of parts to meet the stringent requirements of medical, aviation, automotive and other industries. Relying on advanced surface treatment equipment and strict quality control, we ensure the quality delivery of the entire process from micron-level processing to terminal protection.
