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Reference Chart

Anodizing Color & Thickness Chart

Visual reference for anodizing types, available colors, thickness ranges, and specifications for aluminum parts. Covers Type II (decorative) and Type III (hardcoat) anodizing per MIL-PRF-8625.

Showing 13 of 13 finishes
Color ▲ Type ▲ Thickness Range (mils) ▲ Thickness (µm) ▲ Hardness (HV) ▲ Spec Reference ▲ Best For ▲
ClearType II0.2 – 1.05 – 25200 – 400MIL-PRF-8625 Type II, Class 1General protection, clear cosmetic finish
BlackType II0.3 – 1.08 – 25200 – 400MIL-PRF-8625 Type II, Class 2Consumer electronics, tactical, instruments
RedType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Safety markings, consumer products, branding
BlueType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Aerospace identification, consumer goods
GoldType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Decorative, premium consumer products
GreenType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Military, color coding, branding
GreyType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Industrial, understated cosmetic finish
OrangeType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Safety markings, high visibility parts
PurpleType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Custom branding, consumer electronics
BronzeType II0.3 – 0.88 – 20200 – 400MIL-PRF-8625 Type II, Class 2Architectural, decorative hardware
Clear (Natural)Type III1.0 – 4.025 – 100400 – 700MIL-PRF-8625 Type III, Class 1Wear surfaces, sliding fits, military
BlackType III1.0 – 4.025 – 100400 – 700MIL-PRF-8625 Type III, Class 2Firearms, aerospace, high-wear components
Dark GreyType III1.0 – 3.025 – 75400 – 700MIL-PRF-8625 Type III, Class 2Industrial wear parts, defense applications
No finishes match your search. Try a different term or filter.

Quick Answer: What Is the Difference Between Type II and Type III Anodizing?

Anodizing is an electrochemical finish that grows a hard oxide layer on aluminum. Type II (sulfuric acid) is decorative and mildly protective at 0.2–1.0 mils thick and takes a wide range of dye colors. Type III (hardcoat) is thicker at 1.0–4.0 mils and much harder at 400–700 HV, giving superior wear resistance but only darker colors. Both follow MIL-PRF-8625.

This chart lists anodize types, colors, thickness ranges and hardness with: dye color, anodize type, thickness in mils and microns, Vickers hardness, MIL-PRF-8625 spec reference and best-use application. Inputs include the color you want and whether you need a Type II decorative or Type III hardcoat finish.

Key facts: Type II 0.2–1.0 mils (5–25 µm), 200–400 HV, full color range | Type III 1.0–4.0 mils (25–100 µm), 400–700 HV, black, dark grey and natural | dimensional growth ≈ 50% of total thickness per side | 6061-T6 gives the most uniform color.

Notes on This Chart

  • All specifications reference MIL-PRF-8625 (formerly MIL-A-8625). Class 1 = undyed, Class 2 = dyed.
  • Hardness values are Vickers (HV). Type III hardcoat can reach 65-70 HRC equivalent.
  • Actual color appearance varies by alloy, temper, and surface finish. 6061-T6 produces the most uniform colors.
  • Dimensional growth is approximately 50% of total coating thickness per side.
  • Color swatches are approximate representations. Request samples from your anodizer for critical color matching.

MIL-A-8625 Buildup vs. Penetration Simulator

Anodizing is an electrochemical process that converts the aluminum surface into an aluminum oxide coating. Unlike plating, which only builds up on top of the surface, anodizing grows 50% into the material (penetration) and 50% outward (buildup). Adjust the slider to see how this affects final part dimensions.

0.50 mils (12.7 µm)
Buildup (Growth per side): +0.250 mils (6.35 µm)
Penetration (Base consumption): -0.250 mils (6.35 µm)
Total Diametral Change: +0.50 mils (12.70 µm)
0.25 mil 0.25 mil ANODIZE BUILDUP (OUTWARD GROWTH) ANODIZE PENETRATION RAW ALUMINUM SUBSTRATE ORIGINAL SURFACE

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Frequently Asked Questions

What is the difference between Type II and Type III anodizing?

Type II is a decorative and mildly protective anodize with a thickness of 0.2 to 1.0 mils. It accepts a wide range of dye colors. Type III, also called hardcoat, is much thicker (1.0 to 4.0 mils) and significantly harder (400-700 HV). Type III provides superior wear and abrasion resistance but is limited to darker colors like black, dark grey, and natural.

What aluminum alloys can be anodized?

Most aluminum alloys can be anodized. The 5xxx and 6xxx series (like 6061 and 5052) anodize best with uniform color. The 2xxx series (like 2024) and 7xxx series (like 7075) can be anodized but may show color variation due to high copper or zinc content. Cast alloys generally produce a less uniform finish than wrought alloys.

How does anodizing affect part dimensions?

Anodizing grows both inward and outward from the original surface. Roughly 50% of the total thickness penetrates into the base metal and 50% builds up above it. For Type II at 0.5 mils total, expect about 0.25 mils per side of dimensional growth. For Type III at 2.0 mils total, expect about 1.0 mil per side. Account for this in your tolerancing.

Can you color-match anodized parts?

Exact color matching is difficult because the final color depends on the alloy, temper, surface finish, and bath chemistry. Different alloys in the same batch can appear slightly different. For best results, use the same alloy and temper across all parts, and specify a color sample or Pantone reference for your anodizer to target.

What MIL-SPEC covers anodizing?

MIL-PRF-8625 (formerly MIL-A-8625) is the governing specification for anodizing of aluminum alloys. It defines Type I (chromic acid), Type II (sulfuric acid), and Type III (hardcoat sulfuric acid) processes. It also defines Class 1 (non-dyed) and Class 2 (dyed) finishes. Most commercial and aerospace anodizing references this spec.

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