Cold Spray: Over 30 Years of Development Toward a Hot Future

Abstract

Cold Spray (CS) is a deposition process, part of the thermal spray family. In this method, powder particles are accelerated at supersonic speed within a nozzle; impacts against a substrate material triggers a complex process, ultimately leading to consolidation and bonding. CS, in its modern form, has been around for approximately 30 years and has undergone through exciting and unprecedented developmental steps. In this article, we have summarized the key inventions and sub-inventions which pioneered the innovation aspect to the process that is known today, and the key breakthroughs related to the processing of materials CS is currently mastering. CS has not followed a liner path since its invention, but an evolution more similar to a hype cycle: high initial growth of expectations, followed by a decrease in interest and a renewed thrust pushed by a number of demonstrated industrial applications. The process interest is expected to continue (gently) to grow, alongside with further development of equipment and feedstock materials specific for CS processing. A number of current applications have been identified the areas that the process is likely to be the most disruptive in the medium-long term future have been laid down.

Selective Surface Metallization of 3D-Printed Polymers by Cold-Spray-Assisted Electroless Deposition

“…Moreover, the water droplet likely stayed on the metallized layer peaks above the surface entrapping as stated in Cassie–Baxter wetting state, which can lead to shrinkage of the droplets, resulting in a larger CA. Besides, previous studies reported that the hydrophobic performance of the as-CS surfaces is also attributed to the hierarchical architectures of the dendrite-shaped feedstock Cu powders . Overall, in the present study, CS with dendrite-shaped Cu particles (Figure a) increased the hydrophobic properties of the polymer surface.…”

“…Besides, previous studies reported that the hydrophobic performance of the as-CS surfaces is also attributed to the hierarchical architectures of the dendrite-shaped feedstock Cu powders. 57 Overall, in the present study, CS with dendriteshaped Cu particles (Figure 1a) increased the hydrophobic properties of the polymer surface.…”

Understanding cold spray technology for hydroxyapatite deposition

“…As a result, CS is a suitable approach for spraying compounds that are delicate to oxygen and temperature, producing deposits with the same chemical composition as the input. On the other hand, metals flex plastically when they strike a surface and bind to it by kinetic compaction [29]. Despite recent research addressing their deposition methods, which are greatly influenced by the feedstock's characteristics, ceramics are more challenging to spray [31][32][33][34].…”

Crystal Plasticity Modeling to Capture Microstructural Variations in Cold-Sprayed Materials

“…While interparticle (intersplat) bonding and residual stress-related issues limit the mechanical properties and performance of CSAM parts, the microstructural characterization of the as-sprayed and the post-processed condition of the material has shown increased particle-particle bonding within cold-sprayed materials [15,16]. In particular, Aluminum 6061 (Al6061) is explicitly studied for cold-spray technology research due to its remarkable plasticity required for bonding at a relatively low critical velocity [17][18][19]. Besides being a lightweight material, Al6061 is resistant to corrosion, stress, and cracking, and its high magnesium and silicon alloying provide improved strain hardening, tensile strength, and performance at higher temperatures without breaking down, making it an effective structural candidate as a cold-sprayed material [20].…”