Alodine Surface Finish Supplier In China
Alodine, also known as Chem-Film or chemical conversion coating, is a chemical process that creates a thin, protective layer on aluminum and its alloys. This coating provides excellent corrosion resistance and serves as a highly effective primer for paint and adhesives, while maintaining electrical conductivity. As a specialized supplier in China with deep expertise in aerospace and electronics manufacturing, Celerity Precision offers certified Alodine finishing (conforming to standards like MIL-DTL-5541) to protect your critical aluminum components from environmental degradation and ensure superior surface adhesion.
For certified, high-performance Alodine finishing that meets the most stringent industry standards, partner with Celerity Precision.
Your Alodine Finish Manufacturer
At Celerity Precision, we don’t just apply a finish; we manufacture a fully compliant surface solution. Our Alodine process is managed in-house within a dedicated chemical processing line, where we have precise control over every variable. Our technicians expertly manage the multi-stage process, including alkaline cleaning, deoxidizing, and immersion in the chromate conversion bath, followed by meticulous rinsing and drying. We control the chemical concentrations, temperature, and immersion time to ensure the resulting coating is uniform, adherent, and meets the specific Type and Class (e.g., Type I, Class 1A or Type II, Class 3) required by your specifications.
As your direct manufacturing partner, we understand the importance of masking. We skillfully protect threaded features, grounding points, and tolerance-sensitive areas to ensure the final part functions perfectly. By integrating Alodine finishing with our precision CNC machining services, we provide a streamlined, single-source solution. This eliminates logistical risks and guarantees that the parts you receive are not only dimensionally accurate but also fully protected and ready for assembly in demanding aerospace, military, and electronic applications.
Ensure your aluminum parts have the protection they need. Upload your design files to Celerity Precision for a comprehensive quote that includes our expert Alodine finishing.
Alodine: Technical Specifications
| Feature | Description |
| Surface Roughness (Ra) | Minimal Impact. The coating is extremely thin (typically < 1 μm) and follows the contours of the surface, so it has a negligible effect on the original Ra value of the machined part. |
| Applicable Materials | Exclusively for Aluminum alloys (e.g., 6061, 7075, 5052). |
| Cosmetic Availability | Functional. The primary purpose is corrosion protection and paint adhesion. The color is a result of the chemical reaction and can have slight variations in hue, so it’s not a decorative finish. |
| Visual Appearance | Type I (Hexavalent Chromium): A translucent, iridescent gold to light brown color. Type II (Trivalent Chromium / RoHS compliant): Clear to a very light, near-colorless iridescent blue hue. |
Advantages of Alodine Surface Finish
Excellent Corrosion Resistance
Provides a robust barrier against oxidation and corrosion for aluminum alloys, especially in saline or humid environments.
Maintains Electrical Conductivity
Unlike anodizing, the thin coating allows for excellent electrical conductivity, making it ideal for electronic chassis and grounding points.
Superior Paint and Adhesive Primer
Creates a chemically active surface that dramatically improves the adhesion of paints, powder coatings, and structural adhesives.
Minimal Dimensional Change
The coating is exceptionally thin, adding virtually no thickness to the part, making it suitable for high-precision components.
Cost-Effective Protection
Offers a lower-cost alternative to anodizing for applications where corrosion resistance and paint adhesion are the primary goals.
RoHS Compliant Options Available
Type II Alodine (trivalent chromium) is available for applications requiring compliance with environmental regulations.
Alodine Design Considerations
Specify Type and Class
Clearly state the required specification on your drawing (e.g., "Alodine per MIL-DTL-5541, Type II, Class 1A") to ensure the correct chemical process is used.
Masking Requirements
Identify any areas that must remain free of the coating (e.g., for specific surface conductivity measurements) so they can be properly masked.
Surface Preparation is Key
The quality of the finish is highly dependent on the cleanliness of the part. Our process includes multi-stage cleaning to ensure a perfect result.
Low Abrasion Resistance
The coating is soft and provides minimal resistance to wear and scratching. For high-wear applications, consider hardcoat anodizing instead.
FAQ
What is the difference between Alodine and Anodizing?
Alodine is a thin chemical conversion coating that maintains electrical conductivity. Anodizing is a thicker, harder electrochemical process that creates an aluminum oxide layer which is an electrical insulator.
Is Alodine the same as Chem-Film or Iridite?
Yes, these are all trade names for the same type of chemical conversion coating for aluminum.
Which type should I choose, Type I or Type II?
Type I (hexavalent chrome, gold color) offers the best corrosion protection but is not RoHS compliant. Type II (trivalent chrome, clear/blue) is RoHS compliant and is the standard for most new designs.
How much does Alodine add to the part's dimensions?
Virtually nothing. The coating is extremely thin, so you do not need to make dimensional allowances for it in your design.
Is the gold color of Type I a form of plating?
No, the color is a natural result of the chemical reaction between the chromates and the aluminum surface. It is not a plated layer.
Can you Alodine steel or other metals?
No, the Alodine process is specifically formulated for aluminum and its alloys.
How durable is the Alodine coating?
It provides excellent corrosion protection but is very soft and can be easily scratched. It is not designed for wear resistance.
Why is it used so often in the aerospace industry?
Because it provides a lightweight, corrosion-resistant, and electrically conductive surface that is a perfect primer for the high-performance paints used on aircraft.
Do I need to clean the parts before sending them for Alodine?
No. As part of our manufacturing process, we perform a thorough multi-stage cleaning and deoxidizing of every part immediately before the Alodine process to ensure perfect adhesion.
How do I specify Alodine on a technical drawing?
The best practice is to reference the military specification: “Finish per MIL-DTL-5541, Type II, Class 1A.” If you are unsure, simply writing “Alodine, RoHS compliant” is also acceptable, and our engineers can assist.