Anodizing — Connect with Top Providers
Anodizing creates a controlled oxide layer on aluminum parts through an electrochemical process, providing excellent corrosion resistance, wear resistance, and color options.
About Anodizing
Anodizing is an electrochemical process that converts the surface of aluminum into a durable, corrosion-resistant aluminum oxide layer. The aluminum part is immersed in an acid electrolyte bath, and electric current causes oxygen ions to bond with aluminum atoms on the surface, growing an oxide layer that is integral to the base metal (not a coating that can peel). The oxide layer can be dyed in various colors before sealing. There are three main types: Type I (chromic acid — thin, for aerospace), Type II (sulfuric acid — standard, most common), and Type III (hard anodize — thick, for wear resistance). Anodizing is the standard finish for aluminum parts in aerospace, electronics, sporting goods, and architectural applications.
Tolerances
Type II adds ~0.001" total; Type III adds ~0.002" total (half grows into the surface)
Lead Time
3-7 business days
Cost Range
$2-$20 per part; volume pricing significantly lower
Compatible Materials
Advantages
- Integral to the base metal (won't peel)
- Excellent corrosion resistance
- Wide color range with dyeing
- Hard anodize provides wear resistance
- Electrical insulation
- Environmentally stable
Limitations
- Only works on aluminum (and titanium)
- Color consistency varies with alloy
- Hard anodize reduces fatigue strength slightly
- Dimensional change must be accounted for
- Masking needed for selective anodizing
- Dark colors easier than light on some alloys
Industries Served
Aerospace
The aerospace industry manufactures aircraft, spacecraft, satellites, and related components requiring the highest standards of precision, quality, and reliability.
Automotive
The automotive industry manufactures vehicles and components, demanding high-volume production, consistent quality, and competitive pricing across a complex global supply chain.
Medical Devices
The medical device industry manufactures instruments, implants, diagnostics, and equipment that must meet stringent regulatory requirements for safety and biocompatibility.
Defense & Military
The defense industry manufactures weapons systems, vehicles, equipment, and components for military applications, requiring the highest security, reliability, and quality standards.
Electronics
The electronics manufacturing industry produces circuit boards, components, enclosures, and assemblies for computing, communications, industrial controls, and consumer devices.
Consumer Products
Consumer products manufacturing produces household goods, appliances, sporting equipment, and personal items through high-volume processes prioritizing aesthetics and cost efficiency.
Anodizing FAQ
What is the difference between Type II and Type III anodizing?
Type II (standard sulfuric acid anodizing) produces a 0.0002"-0.001" thick oxide layer for corrosion protection and aesthetics. Type III (hard anodize) produces a 0.001"-0.004" thick, extremely hard layer (60-70 Rc) for wear resistance and is used on pistons, gears, and sliding components.
What colors can anodized aluminum be?
Type II anodized aluminum can be dyed virtually any color including black, red, blue, green, gold, and purple. Black and gold are the most popular. Clear (natural) anodize preserves the silver aluminum appearance. Color vibrancy depends on the aluminum alloy and anodize thickness.
Does anodizing change dimensions?
Yes, anodizing grows approximately half the oxide thickness into the surface and half outward. Type II adds about 0.0005" per surface. Type III adds about 0.001" per surface. For precision parts, dimension tolerances should account for the anodize buildup.
Is anodizing suitable for outdoor use?
Yes, anodized aluminum is highly weather-resistant. Type II anodized aluminum is standard for architectural applications (window frames, building facades) and can last decades outdoors. Hard anodize (Type III) also provides excellent outdoor durability.
Can anodized parts be re-anodized?
Yes, anodized parts can be stripped (using sodium hydroxide) and re-anodized. This is common for repairing damaged anodize or changing colors. However, each strip-and-anodize cycle removes some base material, so dimensional tolerance must be considered.
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