Natural Anodizing

OX-A is a natural aluminium anodizing treatment in conformity with MIL-A-8625 Type II and ISO 7599 standards.

Corrosion resistance

The OX-A layer protects the base material from corrosion withstanding 336 hours of exposure to salt mist according to the requirements of the MIL-A-8625 standard.

Resistance to light wear and scratches

The aluminium oxide layer formed by the OX-A treatment permits obtaining resistance to scratches and light-wear phenomena.


Compared to other aluminium anodizing treatments, it is cheaper thanks to the high efficiency of the process.

OX-AN black variant

The OX-Atreatment can be pigmented deep black, thereby making the colour uniform on all aluminium alloys.


The OX-A treatment transforms the base aluminium into a compact layer of aluminium oxide. The composition therefore largely depends on the initial alloy.
Al O S Impurities
20÷40% 50÷70% 3÷5% Depending on the alloy
Product technical standards
ISO 7599
MIL-A-8625 | Type II
RoHS Conformity
RoHS conform. No restricted-use substances beyond maximum tolerated concentrations.
REACh Conformity
REACh conform. No SVHC in quantities greater than 0.1% by weight.
Anodizable alloys
Wrought alloys Corrosion resistance Max thickness
Containing high percentages of copper and zinc ★★★☆☆ ★★★★☆
Other alloys ★★★★★ ★★★★★
Casting alloys Corrosion resistance Max thickness
Alloys with Si>8% or Cu>2% ★☆☆☆☆ ★☆☆☆☆
Die-casts with Si<8% or Cu<2% ★★☆☆☆ ★☆☆☆☆
Other alloys ★★★☆☆ ★★★☆☆
Coating thickness
Standard thickness Tolerance
15µm ±5µm
Treatment thickness grows 30% outside and 70% inside the surface of the aluminium piece. The radial dimensional increase is therefore equal to 30% of the treatment thickness. 
Uniform thickness over the entire external surface. Reduced thickness in holes.
Aesthetic appearance
Semi-gloss appearance with light grey colour. The colour tone depends on the base alloy and treatment thickness. Morphology is similar to the machined piece.
Black colour option in OX-AN version
Wear resistance
Resistance to light wear and scratches.
In case of greater need, the OX-HS and OX-W treatments permit obtaining very high wear resistance.
Corrosion resistance
The OX-A treatment permits obtaining high resistance to corrosion and oxidization. It passes the resistance requirements of the accelerated corrosion test in salt mist according to the MIL-A-8625F Type II standard.
Corrosion resistance value Base material
NSS according to MIL-A-8625F
≥336 hours Alloy 6000
Chemical resistance
Approximate values of compatibility with the coating environment. The actual resistance to the environment must in any case be tested in the field.
Hydrocarbons (e.g. petrol, diesel fuel, mineral oil, toluene)
Alcohols, ketones (e.g. ethanol, methanol, acetone)
Neutral saline solutions (e.g. sodium chloride, magnesium chloride, brine)
Diluted reducing acids (e.g. citric acid, oxalic acid)
Oxidizing acids (e.g. nitric acid)
Concentrated acids (e.g. sulphuric acid, hydrochloric acid)
Diluted bases (e.g. diluted sodium hydroxide)
Oxidizing bases (e.g. sodium hypochlorite)
Concentrated bases (e.g. concentrated sodium hydroxide)



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