SBIR-STTR Award

Structural steels found in bridges and railways are damaged over time due to loading and the environmental conditions in which they operate. VRC Metal Systems, LLC in collaboration with research partners at Northeastern University propose to develop novel protective/repair coating materials that can be applied to bridges and railways by using the cold gas spray (CS) technology to improve the wear and corrosion resistance of the existing materials and enable spot repair of cracks and corrosion areas. The top candidate for this cold spray coating is nickel–chromium carbide (Ni-CrC), an extremely high strength, nanostructured metal matrix composite (MMC). Other candidate materials that have shown promise include Stellite 6, 316L, 410 and 420 stainless steel. In general, cold sprayed coatings have crack-retarding compressive residual stresses and a high concentration of dislocation-trapping twin boundaries. The materials can be independently deposited in atmosphere at economic rates up to 200 cm3/hr requiring no special jigs or fixturing to apply (i.e. hand application) and can be applied at low temperatures compared to existing welding practices for repair and augmentation applications. The proposed work will develop a lower cost repair solution for railways and bridges

VRC Metal Systems (VRC) and Northeastern University (NU) propose a joint effort to develop point-of-need hybrid repair technologies, that can be applied specifically to repairing bridge and railways structures. During the feasibility phase I effort, a robust coating repair system was developed and subsequently applied to railway steel. While the repair method worked on large gouges, it failed to bridge narrow cracks. In this work, both VRC and NU will investigate hybrid repair methods, such as, cold spray and secondary processing, cold spray and laser-glazing, wire-arc additive manufacturing (WAAM) and cold spray for the specific purposes of repairing complex geometry and improving the performance of the repair. This phase II program will also investigate additional cold spray repair coating systems, to ensure the most robust repair method is deposited. Lastly, VRC will build and implement a mobile high-pressure cold spray unit and design a mobile trailer system for point-of-need repairs. A complete repair will be demonstrated at the completion of this program.