GMW 14665 Test Standard for Anodized Oxidation Coating on Aluminum

EUROLAB laboratory provides testing and compliance service within the scope of GMW 14665 standard. This specification covers the basic requirements for anodic coatings on aluminum and aluminum alloys.

The anodic coating is an oxide layer produced by the electrolytic oxidation process. The oxide layer provides enhanced corrosion protection. This coating can be transparent or colored. Anodic coatings must be either sealed or painted to maintain their appearance.

Exterior parts, whether transparent or colored, are further classified in terms of chemical resistance and application as follows:

Class A – Extreme alkaline resistance up to pH 13,5. An additional coating is mandatory for Class A.
Class B – High alkaline resistance to pH 13.0.
Class C – alkaline resistance to pH 12.0.

This level of performance can be used in emerging markets or other areas where environments are known to be moderate. It can only be used with a special drawing annotation for parts that are not shared among other regions. If the decorative exterior class is not listed in the drawing, Class B is assumed.

Exterior applications should be limited to the top of the belt line. Applications below the belt line are subject to a special edition and special requirements of a higher level must be defined. Corrosion severity in this area is much higher than above the belt line due to copper (etc.) containing brake dust.

Exterior Applications including painted aluminum parts and hard anodized layers. Hard anodized coatings are characterized by their hardness and thickness of more than 25 μm. For applications that need little corrosion protection as well as high wear protection, the hard anodic layer may not be sealed. For applications that need a very high corrosion protection, but only moderate wear protection, the hard anodic layer needs to be sealed. Anodized coatings used as paint substrates are sealed or partially sealed (for example, 5 minutes in hot water) to ensure the best paint adhesion.

As Eurolab laboratory, we provide the best service to you, our manufacturers, with our experienced and professional staff within the scope of all automotive standards. Our laboratory and test team work diligently to provide the best service for manufacturers.