TT-C-490F Testing

What is TT-C-490F?

TT-C-490F is a Federal Specification that outlines various cleaning, chemical conversion coatings, and pretreatments used to provide preparation for organic coatings on metallic substrates.  It also describes the required testing procedures and pass/fail criteria for such parameters as cyclic corrosion resistance (GMW 14872), salt spray resistance (ASTM B117), and coating adhesion (ASTM D3359).

 

These pretreatments include such processes as zinc phosphate, iron phosphate, and chemical conversion coatings for aluminum (MIL-DTL-5541F).  The organic coatings used over the TT-C490F pretreatments include epoxy primers (MIL-DTL-53022, MIL-PRF 23377, and MIL-DTL-53030), CARC paints (MIL-DTL-53072), and CARC powder coating (MIL-PRF-32348).

 

TT-C-490F provides minimal guidance on actual application procedures, instead recommending applicators to use parameters provided by chemical suppliers.  The number and dimensions of sample panels, as well as the frequency of sample submission is clearly delineated.

 

Rev Level F includes several significant changes from Rev Level E, including usage of an X-scribe on panels (ASTM D1654) prior to corrosion testing exposure, and usage of cyclic corrosion testing (GMW 14872) in addition to salt spray testing (ASTM B117).