John La Scala, division chief for material and manufacturing sciences at CCDC ARL agrees. “It would allow you to have a layer-by-layer differentiation of properties, which could be really useful to achieve high performance,” he says. For example, combat vehicle parts could contain a hard outer shell with softer inner layers for damage tolerance – all achieved through the single process of cold spraying. The technology could also be used for rapid, in-theater repair of combat vehicles.
Hypersonic weapons, which travel at more than five times the speed of sound, are another potential application. La Scala says that cold spray processes could potentially be used to create light, strong, high-temperature resistant carbon-carbon composite hypersonic casings. Among other benefits, this would allow for pyrolysis of each carbon-carbon layer, which would reduce the voids caused by the carbonization process.
Initially, researchers worked with polystyrene because it is a well-characterized material. Now, they are focused on thermoplastics such as polycarbonate and PEEK. Next, they hope to tackle thermosets like vinyl resin and epoxy systems. Since commercially available powder polymers and composites are limited, the team is synthesizing polymers in-house, as well as adding fibers and fill and reducing particle sizes with milling, grinding and microfluidics techniques.
In the long run, this developing technology could benefit numerous industries, including aerospace, automobile and petrochemical. Stanzione and Haas are particularly excited about potential biomedical applications, such as lighter weight, more advanced prosthetics.