"Alodine" is a non-anodic protective coating.   Alodine {aka Iridite, aka Chromate Conversion} is a microscopic thin film commonly prescribed on aluminum to:

• Provide an Excellent surface prep for paint
• Aid in Corrosion Resistance
• Impose desired Electrical 'Resistance' characteristics,                       (commonly prescribed for Radio and Amplifier cabinets.)

SPECIFICATIONS & CERTIFICATIONS:  Alodine Methods and Properties are described in Mil-C-5541 (Now AMS-C-5541)  and AMS-A-2473.  All other Customer Specifications follow the format and guidelines of those documents. The common Spec Call-outs are

• Class 1A:  Standard for Maximum Protection, and
• Class 3:  Minimum thickness for reduced electrical resistance