The project, managed by Integran Technologies Inc. (Integran) in collaboration with Cirrus Materials Science (Cirrus) and Corrdesa, sought to develop an alternative repair technology for worn components that is free of chromium and nickel. Based upon previous proprietary developments by the applicants in the area of nanostructured metal and metal-matrix composites applied by electroplating and selective (brush) plating, a materials technology development and optimization program was conducted to specifically target the cost-effective repair of damaged components and structures.

The overall technical objective of the project was to develop and validate an alternative repair technology based on electrodeposited nanostructured cobalt that meets and/or exceeds the properties and performance of (1) electroplated nickel coatings in both Class 1 (corrosion protection) and Class 2 (engineering plating) applications, as specified in military and aerospace standards for bulk component plating such as MIL-STD-868A and AMS-QQ-N-290; (2) electrolytic hard chrome coatings per AMS-QQ-C-320; and (3) for selective plating, repair, and rebuilds as outlined in MIL-STD-865C.

To develop a nanocrystalline cobalt-phosphorous alloy to meet the above requirements, the primary technical objectives of the project were as follows:

1. Optimize a nanocrystalline cobalt-phosphorus electrodeposition process for repair operations that is based on conventional direct current rectifiers to reduce infrastructure costs associated with pulse plating;
2. Develop novel nanocomposite coating systems consisting of a nanocrystalline cobalt-phosphorus matrix embedded with second-phase hard particles to improve Taber wear performance of nanocrystalline cobalt-phosphorus systems;
3.  Evaluate suitable equipment to enable brush plating for specialized repair using the optimized material; and
4. Reduce repair implementation cost by utilizing state-of-the-art computational fluid dynamic, electroplating, and galvanic corrosion design software to optimize deposition rates and aid in material selection.

The project concentrated on five tasks to address the project objectives:

1. Development and optimization of nanostructured cobalt-phosphorous (nCoP) matrix material: development of plating process for matrix material deposition on steel and aluminum substrates;
2. Development of process to co-deposit hard ceramic, second phase particles: entails development of the process to co-deposit hard ceramic second-phase particles using particle-suspension plating baths as well as Cirrus dopant technology based baths;
3. Development of specialized repair methods via brush plating: development of brush plating method, plating deposits developed in first two tasks, suitable for repair applications;
4. Optimized (final) process stand-up: scale-up of the process developed in the preceding tasks and optimization of the coating process; and
5. Coating characterization, testing and evaluation: characterization of deposits produced in fourth task, used for feedback for effective process and material optimization and validation.

The overall project breakdown is: the first task was aimed at optimizing the nCoP matrix; the second task involved the investigation of co-deposition of second phase particles in the nCoP matrix to enhance mechanical properties; and the third task involved the design and development of nCoP and nCoP-particle brush plating system suitable for repair operations and consequent scale up for the fourth task and validation testing in the fifth task. The findings of every task were used in the development of the succeeding tasks.

Integran, in collaboration with Cirrus and Corrdesa, successfully completed Strategic Environmental Research and Development Program (SERDP) Project WP-2609, in which a cost-effective nCoP composite alloy was successfully developed for the repair and refurbishment of damaged components for use within the US Department of Defense (DoD). Validation testing performed in the project demonstrated that the novel nanostructured composite coatings meet and/or exceed the properties and performance of electroplated nickel coatings and Electrolytic Hard Chrome (EHC) and can be successfully applied to steel and aluminum components. The development efforts in the project built upon the core Nanostructured Cobalt-Phosphorus technology that was successfully demonstrated and validated at the Fleet Readiness Center - Southeast (FRC-SE) in Environmental Security Technology Certification Program (ESTCP) Project WP-200411.

In terms of overall benefits, the report states the following in regards to EHC replacement and nickel replacememt:

• EHC replacement: All cobalt-phosphorous alloy (CoP)-based configurations (CoP, CoP-Diamond, CoP-Silicon Carbide, and CoP-Alumina Dopant) are fully dense, with great corrosion performance, good hydrogen embrittlement resistance, and better sliding wear performance and ductility than EHC. This makes CoP a suitable candidate for applications requiring good sliding wear properties such as hydraulics. For applications that require superior Taber wear resistance, CoP-Diamond system is a suitable replacement for EHC as it can be deposited at 125μm/hour vs EHC 15μm/hour. The fast deposition rate is also an asset for quicker repairs.
• Nickel replacement: All down-selected systems: CoP, CoP-Diamond, CoP-Silicon Carbide, and CoP-Alumina Dopant display better taber wear and hardness properties than Electroplated Nickel Metal (Ni).