Ricerc@Sapienza

Process optimization and quality control are important issues in cold spraying and coating development. Because the cold spray processing is based on high kinetic energy by high particle velocities, online spray monitoring of particle inflight properties can be used as an assisting process tool. Particle velocities, their positions in the spray jet, and particle size measurements give valuable information about spraying conditions. This, in turn, improves reproducibility and reliability of coating production.

Cold-gas spray (CGS) deposition of amorphous steel coatings starting from a commercial feedstock powder containing boron, tungsten, and silicon was investigated. Microstructural
characterization, carried out by X-ray diffraction (XRD), transmission electron microscopy, and backscattered electron diffraction (EBSD) analysis, confirmed the amorphous nature of deposited
coatings. The amorphization phenomenon is related to high-strain/strain-rate deformation with shear instability caused by very high particle kinetic energy, with a mechanism that resembles the severe