TT-C-490 Chemical Conversion Coatings And Pretreatments For Metallic Substrates Base For Organic CoatingsThis specification covers processes, pretreatments, and pre-primer surface preparations of metallic substrates for coating applicators. It covers metal surface preparation for delaying corrosion initiation and promoting primer adhesion. In addition, this specification covers the testing requirements for qualification of conversion coatings, the pretreatments and pre-primer coatings.