Standard Specifications:
MIL-A-8625 Type II, Class 1 & II • AMS 2471 and AMS 2472
Sulfuric anodizing has superb dielectric strength, good abrasion resistance, and excellent corrosion resistance. Type II anodizing has a naturally decorative appearance and lends itself readily to clear and color work, as the coating is more transparent than other types of anodizing. It serves as a base for color absorption to create decorative finishes because dyes can be deposited into the pores of the anodized layer and then sealed. The result is a highly desirable, rich, intense, permanent color finish. Type II anodizing is also used where a colorless film is important, as for ornamental purposes or reflectors.
Properties
Type II Sulfuric Anodizing improves the performance of your parts for:
• Wear Resistance
• Lubricity
• Dielectric Properties
• Heat Dissipation
• Corrosion Resistance
• Bonding
• Aesthetics
Please visit the Dye Anodize Section for
detailed information on our dye anodize process and color selections.
To view the Comparison between Type II and Type III Anodize PDF click on the link in the Resource section to the right.
For critical applications, please consult with your Pioneer Metal Finishing sales engineer. To contact a specialist click on the finishing expert email link in the resource section to the right.
Oxidation of Aluminum
Anodizing entails the immersion of an aluminum part into an electrolyte bath where an electric current is passed through the part. During this process an anodic coating penetrates and grows on the base
metal by converting the aluminum to aluminum oxide. The ratio of growth/penetration
for anodic coatings is typically 50/50*, resulting in a coating between .0001" and .001" thick.
To see the Growth/Penetration Video click on the link in the resource section to the right.
Proper formation of aluminum oxide coatings provides extreme hardness, a naturally decorative appearance and increased resistance to corrosion and abrasion. In addition, it serves as a base for color absorption to create decorative finishes.
Sealing the Anodized Part
The final processing step of clear or dyed anodized part is a sealing treatment to close the pores of the aluminum oxide and render the coating non-absorptive. Sealing is accomplished by immersion in deionized
water containing either nickel acetate, nickel fluoride, sodium dichromate or near boiling ionized
water (water chemically distilled to a high degree of purity).
Sealing Anodize Yields:
• Increased Corrosion Resistance
• Better Lubricity
• Better Light Fastness
• Better Weather Fastness
Each alloy anodizes differently because alloy metals change the conductivity of the part and cause it to form aluminum oxide, either faster or slower. All aluminum can be anodized, but some alloys work better than others. Castings tend to give the anodizer the most problems because of the porosity in the castings and alloying materials used. For applications requiring maximum corrosion protection visit the EnduraGuard™ section, or click on the EnduraGuard™ PDF in the resource section to the right to learn more about Pioneer's new breakthrough finish.
Proper formation of aluminum oxide coatings provides aluminum with a naturally decorative appearance and increased resistance to corrosion and abrasion. Normally between .0001" to .001" thick, sulfuric anodizing lends itself readily to clear and color work, as the coating is more transparent than other types of anodizing. In addition, it serves as a base for color absorption to create decorative finishes. Dyes can be deposited into the pores of the anodized layer and then sealed. The result is a highly desirable, rich, intense, permanent color finish.
Aluminum can be anodized and dyed to match a given decor or to simulate a particular metal. Click here to view our selection of dye colors or select the dye color chart PDF to the right in the Resource Links. For Custom designs in anodizing, please visit our Pioneer Metal Fx™ section.
Each alloy anodizes differently because alloy metals change the conductivity of the part and cause it to form aluminum oxide, either faster or slower. All aluminum can be anodized, but some alloys work better than others. Castings tend to give the anodizer the most problems because of the porosity in the castings and alloying materials used. For applications requiring maximum corrosion protection visit the EnduraGuard™ section, or click on the EnduraGuard™ PDF in the resource section to the right to learn more about Pioneer's new breakthrough finish.
Sulfuric anodizing has superb dielectric strength, good abrasion resistance, and excellent corrosion resistance. Type II anodizing is mostly used for decorative anodizing as it lends itself to the dying of light and dark colors, depending on the coating thickness. Where a colorless film is important, as for ornamental purposes or reflectors, Type II anodizing is used. There are some disadvantages to consider when contemplating the sulfuric acid process. The following types of parts should be avoided due to the corrosion nature of sulfuric acid: assembled parts, parts containing welds, joints, and recesses in which the anodizing solution may be retained.
