What is chromate conversion coating?
Chromate conversion coating is a process used to protect aluminum and some other metals from corrosion, commonly known as rust. Corrosion is caused by the reaction of metals and oxygen with moisture or water. Rust is an oxide of metal in which oxygen atoms react chemically with metal atoms. If not corrected, oxidation or rust will occur at high humidity rapid damage to metal parts in weather.
• Copper and copper alloy chromate treatment
Function: Copper and copper alloy chromate passivation, not only can improve the corrosion resistance but also can make the surface polished copper and copper alloy surface dirt is more serious need to first soak in cold emulsifier and then clean with hot emulsion, and then clean with water to remove oil.
• Aluminum and aluminum alloy chromate treatment
Aluminum and aluminum alloy chromate treatment can obtain a chemical conversion film on which is completely different from anodizing, which is composed of complex compounds, and has a certain protective performance with the film layer at the same time, does not lead to a significant impact on the size of the part and its electrical conductivity. In addition, the high frequency conductivity of aluminate film on aluminum is quite high.
Process flow
- Cleaning preparation: The metal surface needs to be thoroughly cleaned before chromate surface treatment to remove any impurities or dirt.
- Pretreatment: Surface pretreatment is an important step of chromate surface treatment. First, the metal surface is soaked in an acid cleaning agent to remove surface oxidation.
- Contaminants such as rust and grease.
- Degreasing and degreasing: Soak the metal surface in degreasing agent to remove the grease on the surface,
- Cleaning: After washing the surface, rinse it thoroughly with water to ensure that the surface is clean.
- Chromate treatment: The chromate solution is sprayed or impregnated on the metal surface, and reacts at a certain temperature within a certain time,6. Neutralization: neutralize the metal surface with water or lye to remove chromate residue.
- Cleaning: Clean the surface with clean water to prevent turbidity or white scale and other phenomena.
- Drying: Dry the surface or blow dry with a dryer, and proceed to the next step as soon as possible.
Application field
Chromate surface treatment is suitable for a variety of metal materials, such as stainless steel, aluminum alloy, galvanized sheet, nickel alloy, etc., and is widely used in aerospace, machinery manufacturing, automobile manufacturing, electronics and other fields. Especially for the easily corroded metal surface treatment, can effectively improve its anti-corrosion performance and service life.
