Anodization

Focus

We are an operation compartment for surface finishing focused on anodizing. Our services include coating of aluminum castings and aluminum 99.9% plus all common aluminum alloys used in industrial and medical applications.

Name Usability for anodization
New Old EU-Norm DIN 10725-1 Functional Decorative
Forgeable alloys DIN EN 573-3
Al99,8(A) Al99,8(A) EN AW-1080A 3.085 excellent excellent
Al99,5 Al99,5 EN AW-1050A 3.0255 excellent good
Al99,0 Al99,0 EN AW-1200 3.0205 excellent acceptable
AlCuBiPb AlCuBiPb EN AW-2011 3.1655 not recommended inapplicable
AlCuSiMn AlCu4SiMg EN AW-2014 3.1255 acceptable inapplicable
AlMn1 AlMn1 EN AW-3103 3.0515 excellent insufficient
AlMn0,5Mg0,5 AlMn0,5Mg0,5 EN AW-3105 3.0505 acceptable acceptable
AlMg1(C) AlMg1 EN AW-5005A 3.3315 excellent good
AlMg3Mn AlMg2,7Mn EN AW-5454 3.3537 good insufficient
AlMg4,5Mn0,7 AlMg4,5Mn EN AW-5083 3.3547 good insufficient
AlMg3 AlMg3 EN AW-5754 3.3535 excellent good
AlMg1SiCu AlMg1SiCu EN AW-6061 3.3211 excellent acceptable
AlSi1MgMn AlMgSi1 EN AW-6082 3.2315 excellent acceptable
AlZn4,5Mg1 AlZn4,5Mg1 EN AW-7020 3.4335 good acceptable
Cast alloys DIN EN 1725
G-/GK-AlSi12 AlSi12

3.2581 insufficient inapplicable
G-/GK-/GF-AlSi7Mg AlSi7Mg

3.2371 insufficient inapplicable
G-/GK-/GF-AlMg3 AlMg3

3.3541 excellent excellent
G-/GK-AlMg5 AlMg5

3.3561 excellent excellent
Cast alloys DIN EN 1706
G-/GK-AlSi10Mg(a) AlSi10Mg

EN AC-43000

3.2381 not recommended inapplicable
G-/GK-AlSi10Mg(Cu) AlCi12Cu

EN AC-43200

3.2383 not recommended inapplicable
G-/GK-/GF-AlMg3(a) AlMg3

EN AC-51100

3.3541 excellent excellent
G-/GKAlMg5 AlMg5

EN AC-51300

3.3561 excellent excellent

Source: Aluminium-Werkstoff-Datenblätter, Aluminium-Verlag
1. Depending on the alloy, the oxide layers generated in alloy typical color casts.
2.When machine parts created of different aluminum alloys colordifferences may happen.

Technique

We operate one of the most modern rectifier systems in our house. The anodising is automatically performed and stopped when the preset thickness is reached.
Capability: L x B x H 800mm x 300mm x 500mm

Chemical pre-treatment

Aluminum objects cannot be oxidized chemically or anodically easily. Dirt, oil, grease, coolants and abrasives as well as roll, pressing, blooming and cast skins need to be removed in the chemical pretreatment. A clean surface is mandatory for a uniform oxide layer.
Not all listed methods are possible in architecture and / or industry.

a) Degreasing

In this first wet chemical level in all chemical or electrochemical treatments all traces of organic substances are removed thoroughly. The parts are treated in alkaline aqueous cleaning baths. Grease and oils are emulsified, other fouling are replaced and dispersed.
Note: Silicone oils, silicone-containing release agent or dried, not emulsifiable operating materials may require additional effort (eg. Use of solvents or abrasive degreasing by hand).

b) Mordanting (E0*)

After degreasing the aluminum parts are normally stained. This is done in an alkaline pickling bath (chromic acid anodization = acidic pickling baths), which removes the last traces of grease, dirt and natural oxide layer.
Note: Complete removal of the oxide layer is essential for the uniform layer structure in the following oxidation. Fully machined, precision components pickling is reduced to a minimum or even omitted for reasons of dimensional stability.
A precondition in these cases is a clean delivery of the parts without adherent dirt. Only this way the proper structure of the layers can be guaranteed.

c) Chemical gloss (E7*)

For reflectors, fittings, ornaments and selected equippment components of aluminum often a maximum gloss and reflectivity is desired.
A maximum of gloss and reflectivity is often desired when it comes to reflectors, fittings, ornaments and selected equippment components of aluminum. Mechanically mirror finished aluminum surfaces have a reflectance of only 70 percent. To protect and preserve the gloss an anodic oxide film is necessary, but it also reduces the reflectivity by another 5 to 15 percent. Chemical brightening and a subsequent oxidation shield increases the reflectivity up to 80 percent. By chemical removal of 5-10 microns the aluminum gets smoothed, so it obtains a shiny surface.
Note: High gloss levels can only be achieved using pure (99.8%) and purest (99.9%) aluminum.

d) Abrasive blast cleaning

A suitable blasting agent (corundum, aluminum granules, glass beads etc.) is thrown onto the metal surface by compressed air. The workpiece’s surface is cleaned, deburred and can even be decorative refined. The effect of blasting can hereby be controlled by choosing a proper abrasive.
Source: http://www.vsa-asa.ch/jwa/de/anodisieren/vorbehandlung/vorbehandlung_details.jsp

Anodization

The anodization of aluminum – also called anodic oxidation – is a proven and common for surface finishing of aluminum. The aluminum surface is changed into aluminum oxide in an electrochemical process. The oxide layer is ceramic hard, transparent, and, in contrast to other finishing processes, firmly connected to the base material. The film thickness can be selected depending on the intended use of the workpiece. Anodizing is applied to preserve the valuable metallic character of aluminum in architecture (eg. facades) and indurstry (eg. medical, aerospace, machinery industry).

Electrochemical coloration

According to costumer request all generated layers can be colored. It is black, natural bright/lucid and chemically shiny bright/lucid or black. Other colors can be made feasible by request and special agreement.

Properties

Different specialized anodising allows us to go into your specific application area or the required layer properties. The common DC anodizing (DC / sulfuric acid method) is in the foreground. Anodic oxide layers are compacted at the end of the process and creates a sealed homogeneous oxide layer. This procedure is essential for the quality of the oxide layer.

http://erko-eloxal.de/wp-content/uploads/2016/03/Material-Tabelle-web.pdf
This link includes a table that contains the entire alloys and its capability of anodising. It would be great if you make use of that table when you are requesting.