Surface Finishing, Industry Knowledge

Surface Finishing：What is anodizing?

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Anodizing component machining

Anodizing is an electrolytic process that creates a durable, corrosion-resistant oxide layer on the surface of aluminum (and other non-ferrous metals like titanium). This layer is integral to the metal—unlike paint or plating, it won’t peel or chip—and can be dyed in vibrant colors for aesthetic or functional purposes.

How It Works

The process immerses the metal part in an electrolytic bath (typically sulfuric acid) and passes an electric current through it: the part acts as the anode, causing oxygen ions to react with the metal surface and form a porous aluminum oxide (Al₂O₃) layer. The pores are then sealed (via hot water or chemical treatment) to lock in color and boost corrosion resistance, or left open for specialized coatings (e.g., lubricant retention).
  • Corrosion resistance: The oxide layer shields aluminum from moisture and chemicals, ideal for outdoor or marine applications.
  • Wear resistance: Harder than bare aluminum, it withstands scratches and abrasion (hard anodizing can reach 60+ HRC).
  • Aesthetic flexibility: The porous layer absorbs dyes, enabling custom colors (black, red, gold) while maintaining a metallic finish.
  • Adhesion: Improves bonding for paints or adhesives, enhancing durability of secondary coatings.

Common Uses

Anodizing is widely used in aerospace components, automotive parts, consumer electronics (e.g., phone casings), architectural trim, and industrial machinery—anywhere aluminum needs enhanced performance or visual appeal.
It’s a cost-effective, eco-friendly process that extends the lifespan of aluminum parts while adding customizable value.

  • Some common anodizing Color

Anodizing alone cannot conceal tool marks, so for cosmetic parts during processing, we typically need to confirm whether sandblasting should be carried out in conjunction with anodizing.

This is especially true for natural anodizing—differentiation can only be made by subtle details, as the finish typically has a distinct luster compared to the base metal’s natural appearance after anodizing.

clear matte anodized part factory
blue anodized component
brown anodized component
black anodized component bright

This is the finish after anodizing and sandblasting.

So anodizing can certainly be customized to colors matching Pantone or RAL color charts.

clear anodizing
black anodized component matte

This is the finish after anodizing and sandblasting,BUT this is matte.

No specific notes, we typically apply a bright, metal-toned anodizing finish by default. Any special requirements must be clearly specified in the quotation.

  • Some applications:

Clear anodized+Sandblasting
/120mesh：

  • (including sand blasting, glass bead blasting or dry ice blasting): Applied to create matte, textured finishes or for surface cleaning.
sandblasting parts

Clear anodizedSandblasting/
180mesh：

  • I'm sure you've seen this surface before. Exactly, MacBook!
gradient anodization exposure development polished anodizied

Anodizing can also achieve gradient anodization effects, or create diverse surface finishes through exposure development and laser engraving.

Logo Laser Engraved Formexfabtech

  • Application of Anodizing+ Sandblasting +Masking

  1. CNC Texturing: First, fine knife patterns are carved into the metal surface using CNC machining.

  2. Sandblasting: The surface is treated with high-pressure sandblasting to cover certain areas of the knife patterns, giving it a uniform matte finish.

  3. Anodizing: Anodizing treatment is applied to enhance corrosion resistance while adding color.

This method combines the precision of machining with the matte texture of sandblasting, and the anodizing enhances durability and uniformity of appearance.

application anodizing sandblasting and masking

Certainly, masking techniques can also be used in anodizing to achieve diverse surface effects. The charm of CFM lies in its boundless creativity—and our machining team is committed to turning those ideas into reality.

  • Splatter anodization&Splash-ink anodization

The aluminum alloy shell adopts splatter anodization to achieve a unique artistic texture.

 

Splash-ink anodization is based on conventional anodization. By controlling electrolyte composition, current parameters, or adopting special coloring methods, it forms irregular "splash-ink" textures on the oxide film instead of a uniform single color.

 

FORMEXFABTECH primarily offers processing services for various product designs, ranging from sample development to mass production. If you are looking for a reliable partner, please feel free to contact us.

 

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