Precise Sulfuric-Base Anodize for tight- tolerance machined parts

AnoTole is a breakthrough anodizing technology advanced by Anoplate to produce exacting and predictable anodizing build-up, much like that of Type 1 chromic anodize, using a sulfuric acid-based, Type II electrolyte. Typically the thickness of the coating is less than 0.0001 inch (~2.5 µm) with a nominal build-up per side of about 30 millionths of an inch.

Initially developed as an alternative to chromic acid anodize due to its environmental, worker safety and health concerns, AnoTole avoids the use of hexavalent chromium compounds in either the anodize or the sealing process.

In general, AnoTole is too thin to accept dyes or secondary coloring so it’s offered in natural, undyed color. Sealing is typically done with a trivalent conversion coating which imparts no additional coloration to the anodize but enhances durability and corrosion resistance.

Primary applications include any precise aluminum machined components where tolerances are below 0.001” and the only way parts can be anodized is with extensive masking. In many cases, the coating is so thin and results predictable that expensive masking can be minimized or altogether eliminated.


❖ MIL-A-8625, Type Ic (non-chromic acid anodizing alternative for Type I and Type Ib)
❖ MIL-A-8625, Type IIb (Thin Sulfuric Acid Anodizing)


❖ A minimal buildup of 20-50 millionths of an inch (0.5 to 1.3 micrometers)
❖ Exceeds 336-hour salt spray resistance corrosion test per ASM B117
❖ Can be applied universally to most aluminum alloys
❖ Hexavalent chromium-free coating (ELV, RoHS and WEEE compliant)
❖ Self-limiting thickness; consistent and predictable dimensional change lot to lot.