The objective of this Statement of Need (SON) was to develop environmentally benign processes that replace electrolytic chromium and nickel plating used on maraging steel, corrosion-resistant steel, and aluminum alloys in localized areas of weapons system components. The proposed technology should have met the following requirements:
Proposals submitted must have included theoretical or known deposition rate calculations and existing technical and operational performance data to support the concept. The proposer should have considered similar deposited metal technical characteristic requirements, such as but not limited to: Aerospace Material Specification (AMS) 2406, AMS 2460, and AMS QQ-N-290. Technical data required to successfully transition the proposed method or technology was include, but was not limited to: adhesion, hardness, density, porosity content, corrosion, and no (or a minimal and quantifiable) substrate fatigue debit. Other technical issues expected to be addressed for final Department of Defense (DoD) qualification included cleaning, surface preparation treatments and final machining.
Currently the military has limited ability to execute repair operations on low-risk military items, in part, due to the existing state-of-the-art metallic repair process operational, regulatory, and infrastructure footprints. Preference was be given to technologies that advance state-of-the-art and require limited or no new specialized labor skills and are suitable for front line military field or ship-based operations. Approaches requiring substrate heating or extensive post-treatments were not of interest and were not be considered.
This work will develop a material or technique that: (1) reduces or eliminates dependence on electro-deposition technologies that require intensive and costly infrastructure to prolong the life of military hardware and components, and (2) meets weapon systems’ technical requirements while reducing the DoD’s current weapon systems’ environmental and logistical footprints. When implemented, technologies developed in response to this SON will help DoD components meet their environmental compliance goals.
Military items and components frequently undergo front line maintenance inspection and, when found deficient, are spot repaired or replaced with spare parts to minimize down time. Deficient items are frequently scrapped or returned to repair facilities for more extensive repairs that often include restoring metallic surfaces. Transportation and regulatory costs for repairing metallic plated components are significant expenses for traditional military weapon system life-cycles.
Electrolytic chromium plating is a common repair process typically used on parts for increasing abrasion resistance, increasing tool and die life, maintaining accuracy of gauges, and reconditioning worn or undersized parts. These parts include but are not limited to long shafts, pinions, and gears. Gun barrels (20 mm to 155 mm) use metallic protective coatings on their interior bore surfaces to resist damage from hot propellant gases and the thermo-chemical and mechanical effects of the projectiles passing through the bore. While chromium is effective in many applications, hexavalent chromium solutions are known human carcinogens that are strictly regulated. Management of these operations requires significant fixed infrastructure, operations and environmental and safety controls. The U.S. Occupational Safety and Health Administration (OSHA) regulates worker hexavalent chromium permissible exposure limits (PEL) to 5 µg/m3.
Nickel coating deposition processes, including Electro-less and Sulfamate Nickel, are commonly used for substrate repair. Operational risks result from possible inhalation, ingestion and dermal contact. Existing nickel deposition processes also are impacted by U.S. and international operational and waste environmental regulations complicating transition to military front line locations. Based on the associated hazards, there is concern in the nickel industry that nickel compounds utilized in surface treatment may become subject to strict requirements under the European Union (EU) Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulations. The PEL for nickel and soluble nickel compounds is 1 mg/m3 . Additional limits exist under the U.S Clean Water Act and Safe Drinking Water Act.
The cost and time to meet the requirements of this SON were at the discretion of the proposer. Two options were available:
Standard Proposals: These proposals describe a complete research effort. The proposer should incorporate the appropriate time, schedule, and cost requirements to accomplish the scope of work proposed. SERDP projects normally run from two to five years in length and vary considerably in cost consistent with the scope of the effort. It is expected that most proposals will fall into this category.
Limited Scope Proposals: Proposers with innovative approaches to the SON that entail high technical risk or have minimal supporting data may submit a Limited Scope Proposal for funding up to $150,000 and approximately one year in duration. Such proposals may be eligible for follow-on funding if they result in a successful initial project. The objective of these proposals should be to acquire the data necessary to demonstrate proof-of-concept or reduction of risk that will lead to development of a future Standard Proposal. Proposers should submit Limited Scope Proposals in accordance with the SERDP Core Solicitation instructions and deadlines.