Anodizing Surface Finish Supplier In China
Anodizing is an electrochemical process that grows a durable, corrosion-resistant, and electrically insulating aluminum oxide layer directly from the surface of an aluminum part. This versatile finish can be dyed in a variety of colors for cosmetic appeal or engineered as a “hardcoat” for exceptional wear resistance. As a leading supplier in China for precision-machined components, Celerity Precision offers both Type II (decorative) and Type III (hardcoat) anodizing. We provide a one-stop solution for parts that require both a superior aesthetic finish and robust surface protection.
For vibrant, durable, and precisely controlled anodized finishes on your aluminum components, contact Celerity Precision today.
Your Anodizing Finish Manufacturer
At Celerity Precision, we are more than a supplier; we are a dedicated manufacturer with a deep understanding of the science behind anodizing. Our in-house anodizing lines are equipped with advanced power rectifiers, temperature-controlled tanks, and rigorous chemical monitoring systems. This allows us to precisely control the thickness and density of the anodic layer, ensuring consistent color matching across batches and achieving the specified hardness for Type III hardcoat applications. Our skilled technicians masterfully execute the multi-step process, from etching and desmutting to anodizing, dyeing, and sealing.
As your single-source manufacturing partner, we seamlessly integrate our CNC machining and anodizing services. We understand the critical details, such as how different aluminum alloys (e.g., 6061 vs. 7075) anodize differently and require specific process parameters. We provide expert masking for threads, grounding points, and press-fit features to protect their integrity. This comprehensive control over the entire production chain ensures that the parts you receive are not only dimensionally perfect but also feature a flawless, functional, and durable anodized finish.
Experience the difference that true manufacturing control makes. Upload your specifications to Celerity Precision for a detailed quote on machined and anodized parts.
Anodizing: Technical Specifications
| Feature | Description |
| Surface Roughness (Ra) | Slight Increase. Anodizing can slightly increase the surface roughness as it grows a porous oxide layer. A smoother initial machine finish will result in a smoother final anodized finish. |
| Applicable Materials | Primarily for Aluminum alloys. Titanium can also be anodized (typically for color-coding in medical applications). Not applicable to steel or other metals. |
| Cosmetic Availability | Excellent (Type II). Can be dyed in a wide range of vibrant, uniform colors like black, red, blue, green, gold, etc. Functional (Type III). Color is limited to its natural dark grey/bronze/black. |
| Visual Appearance | Type II: A smooth, satin, or matte finish with a deep, integral color. Type III (Hardcoat): A thicker, often darker (grey to black) layer, which may have a slightly rougher texture. Both types provide a clean, durable appearance. |
Advantages of Anodizing Surface Finish
Exceptional Durability and Wear Resistance
The aluminum oxide layer is extremely hard (especially Type III Hardcoat), providing excellent scratch and abrasion resistance.
Superior Corrosion Protection
The stable, non-porous sealed layer offers robust protection against atmospheric and chemical corrosion.
Aesthetic Versatility (Type II)
Allows for a wide range of vibrant, long-lasting colors that are integral to the surface and won't chip or peel.
Electrical Insulation
The aluminum oxide layer is an excellent electrical insulator, ideal for electronic enclosures and chassis.
Improved Heat Dissipation
The porous nature of the oxide layer before sealing can increase the surface area, improving thermal emissivity for heat sinks.
Dimensionally Stable
The process is highly controllable, allowing for precise and repeatable coating thicknesses.
Anodizing Design Considerations
Dimensional Growth
Anodizing adds thickness. A good rule of thumb is that the layer grows 50% into the surface and 50% out. This must be accounted for in designs with very tight tolerances (e.g., for a 0.02mm thick coating, the surface will grow by 0.01mm).
Sharp Edges and Corners
Sharp external corners can lead to a thinner, less durable coating. A small radius (e.g., 0.5mm) is recommended for optimal coverage and durability. Sharp internal corners can "trap" chemicals and are harder to coat uniformly.
Masking and Grounding
The coating is an electrical insulator. Any areas requiring electrical contact (grounding points) or threads must be specified for masking (plugging).
Alloy Selection
Different aluminum alloys will produce slightly different shades of color, even with the same dye. For consistent color matching across multiple parts, using the same alloy (e.g., 6061) is critical.
FAQ
What is the difference between Type II and Type III (Hardcoat) anodizing?
Type II is thinner, primarily used for decorative color and good corrosion resistance. Type III (Hardcoat) is much thicker and denser, providing superior wear and abrasion resistance, with color as a secondary result.
Will the anodized color ever fade or chip?
Because the color is absorbed into the pores of the aluminum oxide layer itself, it is extremely durable and will not chip or peel like paint. High-quality dyes offer excellent UV resistance and color stability.
Can you anodize steel?
No, anodizing is a process specific to metals like aluminum and titanium that can form a stable oxide layer. Steel is typically protected by plating, painting, or black oxide.
How much size does anodizing add to my part?
The final surface will grow by approximately half of the total coating thickness. For standard Type II, this is often negligible (around 0.005mm-0.01mm). For Type III, it can be significant (up to 0.025mm or more) and must be factored into the design.
Can you match a specific color?
We offer a range of standard colors (black, clear, red, blue, green, etc.). Custom color matching is possible but requires a sample and may involve additional setup costs.
Why do hard-anodized parts look dark grey or black?
The thickness and density of the Type III hardcoat layer naturally create a dark color. It is difficult to dye hardcoat in light or vibrant colors.
Do you mask threads and critical holes?
Yes. This is a standard and critical part of our process. We plug all threaded holes and mask any surfaces specified on the drawing to remain conductive or to maintain their precise machined dimensions.
Will a welded part anodize well?
It can be challenging. The weld filler material and the heat-affected zone of the parent material will anodize differently, often resulting in a noticeable color and texture variation at the weld seam.
Which aluminum alloy is best for anodizing?
The 5xxx and 6xxx series alloys (like 6061) are excellent for both decorative and protective anodizing. The 7xxx series (like 7075) is great for hardcoating but can result in a less uniform color for decorative finishes.
How should I specify anodizing on my drawing?
Be specific. For example: “Anodize, Type II, Class 2, Black, per MIL-A-8625” or “Hardcoat Anodize, Type III, Class 1, Natural, 0.05mm thickness.” If unsure, “Anodize Black” is a common starting point.