- 12 June 2007 -
Defense Specs Keen on ‘Green’

Hazardous materials experts—as well as those with insights on how specifications for the Department of Defense (DOD) are developed—have seen the future of metal finishing for military/defense applications, and the outlook is stark green. Specifically, the DOD is moving toward user- and environmentally friendly chromate- and cadmium-free finishing technologies—areas that heretofore received special regulatory exemptions.

While the destination is clear, the path could be dicey. Observers agree that as finishers and contractors prepare to quickly move in a greener direction, the emphasis will be focused on better collaboration across the board. That was one of the key highlights of several conference sessions delivered at the recent Washington Forum. There, Dr. Keith Legg of Rowan Technology, and Shannon Cunniff, Director, Emerging Contaminants, for the Office of the Deputy Undersecretary of Defense (Installations and Environment), gave attendees a glimpse of the impending challenges in addressing the emerging demands of military and defense customers.

During his presentation, “Defense: Pentagon Coatings Research & the ‘Green’ Future,” Dr. Legg noted that the scrutiny that lead, cadmium, and hex chrome are already receiving in other end-use markets has been creeping into defense. Additionally, he notes, there are also growing concerns relative to nickel, cobalt, and zinc, as well as processes such as nanotechnology. “It’s an issue of how can we better collaborate and come up with a rational approach that really deals with these things,” Dr. Legg explained. The next step, he added, is gathering all the pertinent research for the purpose of developing an “information database.”

And Cunniff knows that mission very well. As the DOD’s point person for emerging contaminants, she cited critical military training activities that were derailed due to possible metal contaminants. “This is an issue that’s having a clear effect on our Armed Forces,” she said. In her mind, it underscores the new mindset that environmental issues must be integrated into DOD, particularly in the way that the department looks at what she referred to as “enterprise risks. We all need to look at the whole life cycle, including cleanup.”

All this, of course, must begin with a thorough understanding of what DOD uses for particular applications. Furthermore, getting a good grasp on what new, clean finishing methods DOD is moving toward and why. For those answers, Dr. Legg points to the summary of the 2006 SERDP/ESTCP Workshop (1), which was compiled over the course of several months following last year’s Washington Forum. The primary objective of the workshop was to strategically guide future environmental research development testing and evaluation (RDT&E) investments and to support the transition of demonstrated technologies in the area of metal plating and finishing. Specifically:

1. Examine the current state of practice in the defense manufacturing and maintenance community;
2. Identify the current and emerging regulatory/other pressures within the U.S. and abroad;
3. review the current non-hazardous alternatives for metal finishing and plating practices;
4. identify the perceived gaps in performance, which limit the transition of non-hazardous alternatives; and
5. identify technical, financial and other barriers to the implementation of less-hazardous or environmentally benign alternatives.

Following are highlights of that summary:

DoD usage of Cr, Cd, Cr6+
Hard chrome, cadmium plate and hexavalent chrome (Cr6+) are used on all weapons platforms. Hard chrome is used for wear resistance, but its primary DOD use is for rebuilding worn and corroded components. Cd is used on most steels to provide sacrificial corrosion protection (as in galvanized steels), including protection against galvanic corrosion between dissimilar metals (such as aluminum and steel that are often in close proximity). It also gives fasteners the proper torque-tension characteristics so that bolted components will not come undone or freeze up. Cr6+, in the form of chromates, is used everywhere, on almost all aluminum surfaces and Cd plated or galvanized components. It is self-healing so that it continues to protect even when scratched. Thus, all aluminum-skinned aircraft are chromated, steel fasteners are Cd plated, and hydraulic rods are chrome plated.

Impact of new U.S. and overseas regulations
Our usage of these materials is being strongly impacted by new environmental regulations, not just in the U.S. but also in Europe, Japan, and even China. The most obvious recent U.S. regulation is OSHA’s Cr6+ PEL released in February 2006. This rule reduced allowable worker exposure by a factor of 10. However, in Europe the ELV, WEEE, and RoHS environmental regulations have severely restricted, and effectively banned, the use of Cd and Cr6+ on vehicles and electrical equipment, as well as mandating the use of lead-free solder.

Even though military uses and aircraft are exempt from the European regulations, the exemptions mean little since the effect is to remove these materials and processes from the commercial market, with the result that they will become increasingly difficult and expensive to obtain. In the long term, as alternatives become more widely available and accepted, it is likely that the exemptions will disappear, subjecting military equipment that the U.S. sells or uses abroad to the same stringent regulations. The WEEE-mandated use of lead-free solder has already caused failures in critical systems, such as satellites and power plants, and is likely to do the same in critical military systems, which must use some COTS hardware.

Drivers for replacement
While Environmental Safety and Occupational Health (ESOH) issues are important, they are not a strong driver for replacement in DOD. The primary drivers are performance and cost, followed by concern over worker safety and the possibility of class-action lawsuits and other liability issues, and the increasing burden of meeting environmental and health regulations.

Barriers to replacement
There are, however, many barriers, both cultural and technical, to replacing the existing technologies in DOD, even where they have been replaced commercially.

1. There is no cohesive Pentagon policy requiring alternatives, and high-level policies are not effectively channeled down to the procurement/sustainment levels.
2. Even in new weapons systems, where procurement contracts encourage the use of clean alternatives, there are often disincentives to the use of new technologies that have a lower life-cycle cost but a higher procurement cost.
3. Military hardware must be reliable above all else. However, materials changes always entail risk, and the management system tends to provide little reward for success but exacts a high penalty for failure. This makes most DOD engineers highly conservative.
4. Hard chrome, Cd, and Cr6+ are so simple and effective, and used so widely, that there are no single drop-in alternatives. There are excellent alternatives, but no single alternative works well in all applications, leaving some applications with no clear cost-effective option. This makes it necessary to obtain accurate and extensive performance and cost data for different applications, and to make that data available to all users, while filling in the remaining gaps.
5. The standard methods of cost analysis tend to mitigate against the use of alternatives, since the old technologies are so cheap and the cost of implementing alternatives is so high. Cost analysis that does not take into account long-term risk, continued availability of hazardous technologies, and sustainment cost is a poor basis for decisions on adopting alternatives.

Adoption of Alternatives in DOD
Alternatives are being adopted in new weapons programs such as the Army Stryker program and the Fighter (JSF), as well as for depot operations. For example:

• Hard chrome plating is being replaced by High Velocity Oxy-Fuel (HVOF) carbide coatings on the landing gear of all new aircraft, military and commercial. Ogden ALC is adopting it throughout landing gear repair operations.
• Cd plating is being replaced by Zn and ZnNi electroplates on Stryker and elsewhere in the aircraft systems such as JSF are replacing Cd with electroplated and vacuum Al coatings and IVD Al). IVD Al is now used by most depots for at least some component overhaul.
• Numerous alternatives to Cr6+ conversion coatings are now available commercially, Chrome Pretreatment (TCP), developed by NAVAIR as a replacement for chromate conversion aluminum, which has proved superior to most other alternatives. TCP is qualified by NAVAIR alloys, and this as well as other alternatives is beginning to be used in military systems.

For the full SERDP/ESTCP report, contact the National Association for Surface Finishing at (202) 457-0630. For more information on hazardous materials alternatives, visit www.hazmat-alternatives.com.

REFERENCES

1. SERDP/ESTCP (Strategic Environmental Research and Development Program; Environmental Security Technology Certification Program.) Summary provided by the 2006 Washington Forum Workshop Steering Committee as well as conference attendees.