Cold, anodized surfaces

[Jean Marc DEFISE]

Posted to CCD-world:
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>From my own experience with space hardware, mineral black anodizing is a
usual process for aluminum parts in optical systems. The natural anodizing
is porous, but in this case it is filled with the mineral dyes used to
blacken the surface. The organic dyes (e.g. used for window frames) are not
suitable for outgassing reasons.

Using mineral anodizing is not considered as a sorb. It is equivalent to
alodine (eridite) coating of aluminum.

On the other hand, uncoated aluminum is naturally covered by the oxyde Al2O3
which is porous. I would say that alodine or mineral anodization is always
preferred for vacuum applications.

Best regards,

Jean-Marc Defise

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Jean Marc DEFISE
CENTRE SPATIAL DE LIEGE
Avenue du Pre Aily B-4031 Angleur BELGIUM
www.ulg.ac.be/cslulg
jmdefise at ulg.ac.be
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