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Projects/Active
Hexavalent
Chromium Coating Alternatives
Project
Number: 08-OC-36
The JG-PP
is partnering with the DoD
services, NASA
and DLA
to support a hexavalent chromium coating alternatives technology survey
focusing on organic coatings. The effort will compile information on prior
work accomplished, identify gaps in the current technology and identify
potential alternatives for future demonstration/validation consideration.
Under the Clean Air Act (CAA),
the Environmental Protection Agency (EPA)
regulates hexavalent chromium emissions as a hazardous air pollutant (HAP)
in accordance with the Aerospace National Emission Standards for Hazardous
Air Pollutants (NESHAP)
rule. Hexavalent chromium is also strictly regulated by the Occupational
Safety and Hazard Administration (OSHA).
To date, there is no single
across the board hexavalent chrome alternative solution. Solutions may
be substrate or process specific. While there have been many studies and
solutions qualified in some applications, there remains a need to provide
a consolidated assessment of the current state of available technologies,
potential demonstration/validation ready alternatives. Consideration will
also be given to establishing a group similar to the Joint Service Solvent
Substitution Working Group that would focus on identifying and validating
solutions for areas that have not yet been able to qualify alternatives.
Organic pretreatments and primers contain hexavalent chromium (Cr+6) as
a corrosion preventive/control element in the coating system. Many studies
have been accomplished to remove the Cr+6 from both of these coatings,
but many studies have looked at specific layers within the coating system.
Organic topcoats are the primary source of barrier-type protection against
environmental degradation of DoD
aircraft, weapon systems and support equipment. They must be resistant
to chemicals, ultraviolet radiation, and moisture, while imparting flexibility
and a cleanable surface. In addition, these materials provide passive
countermeasures against many enemy threats. Hexavalent chromium is not
typically present in topcoats.
The initial effort will focus
on discussions with subject matter experts, key DoD,
NASA
and OEM
sources to establish an information baseline for conducting a detailed
literature and Internet technology search. The results will be compiled
and distributed to participants to share the findings, technology gaps,
and potential courses of action for follow-on efforts.
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