Alodine Yellow [MIL-C-5541]

Alodine Yellow, also known as “Chem Film”, is a chromate conversion coating primarily used to protect aluminum from corrosion. Here are the key points:

Purpose:

• Corrosion Protection: Alodine forms an adhesive aluminum coat, adding an extra layer of protection to the metal surface (a process called passivation).
• Base for Paint Coatings: It serves as an excellent base for paint coatings and priming.
• Preserves Electrical Conductivity: Alodine leaves aluminum unaffected, making it easier to apply paint without altering its properties.

Application:

• Alodine finish is typically applied by dipping, brushing, or spraying onto precision machined parts.
• Widely used in industries such as aerospace, electrical, military, and precision machining.

Film Formation:

• The chromate conversion coating process involves immersing the metal in a chemical bath containing chromium compounds.
  
• The resulting film is not as thick as an anodizing layer but effectively prevents corrosion by eliminating chemical processes.

Remember, Alodine provides excellent corrosion resistance but may not be suitable for decorative finishes due to its limited abrasion resistance.