Preliminary Assessment of a Chemical Pretreatment on Titanium

Author(s):

John Kelley, Thomas Considine, Thomas Braswell, Tyler Sexton, and David Orsini

Abstract:

The need to lighten next-generation vehicles will likely require the use of titanium (Ti) alloys to meet weight requirements. Under the regulation AR 750-1, all Army-based ground equipment is required to have a full Chemical Agent Resistant Coating (CARC) system. The typical CARC system consists of a pretreatment in direct contact with the substrate properly applied in accordance with TT-C-490 prior to applying the epoxy primer and polyurethane topcoat. The current practice for painting Ti involves abrasive blast and applying the CARC system directly to metal. Moreover, applying the CARC system to these multimetal assets can be complicated, since it may not be practical to coat the components and parts separately. This limited-scope investigation examines Bonderite M-NT 7400, a widely used, TT-C-490 qualified product database-listed pretreatment approved for steel and aluminum substrates. This work tests Bonderite M-NT 7400 on Ti using adhesion and accelerated corrosion test methods. The results show Ti surface prepared without a pretreatment and those with the Bonderite M-NT 7400: both provided a good initial and post-ASTM B117-exposed coating adhesion. This suggests that Ti surfaces can be effectively pretreated with adjacent non-Ti surfaces during the same repair/reset operations without masking.