A comparison of the numerical simulation and an experimental study of the collision of the particles and the substrate during detonation spraying is presented. The spraying regimes were chosen to provide unmelted, partially melted, and completely molten particles. The numerical simulation was performed using the smoothed particle hydrodynamics (SPH) method with velocity and temperature settings as initial conditions. Good agreement was obtained between the simulation results and the experimental data, making the SPH simulation suitable for analysis of the deformation of particles and the substrate during detonation spraying. Information about the particle’s shape evolution during the collision is presented. An increase in temperature and plastic strain is analyzed at different points of the particle and substrate. Under certain spraying regimes, it is possible to melt a solid particle due to its high-strain-rate deformation, but no melting of the substrate was observed during the simulation.

In this study, Al₂₁Co₂₂Cr₂₂Fe₁₃Ni₂₂ high-entropy coatings were produced on steel substrates by non-vacuum electron beam cladding of Co, Cr, and NiAl powders. The high-temperature oxidation behavior of the coatings was studied by holding the specimens at 900 °C in air. The microstructure and phase constitution of the samples were studied both in the as-cladded state and after the heat treatment. The microstructure was characterized using light microscopy (LM) and scanning electron microscopy (SEM). Synchrotron X-ray diffraction (SXRD) and energy-dispersive X-ray spectroscopy (EDX) were used to study the phase constitution of the coatings and the “coating-substrate” interface. The coating consisted of disordered bcc (A2), ordered bcc (B2), and disordered fcc (A1) phases. Annealing the coatings for 50 h at 900 °C led to the formation of fcc precipitates in the bcc dendritic grains and a mixture of fcc and σ-phase particles in the interdendritic regions. Needle-like nanosized B2-precipitates were formed due to annealing in the fcc grains at the coating/substrate interface. The microhardness at the top of the as-cladded coating was 585 HV and gradually decreased towards the substrate. A more uniform distribution of the microhardness was obtained after the annealing. Its average value was 441 HV. Rhomboid Cr₂O₃, needle-like Al₂O₃, and spinels of a different morphology were found on the surface of the samples after oxidation at 900 °C.

The structural transformations of the Cr-Ni austenitic steel surface layers during non-vacuum electron beam cladding of the amorphous boron and wetting agents (Cr, Ni, Fe) were investigated. Gas- and hydroabrasive wear resistance of the obtained materials was evaluated. It was shown that the modified layer almost completely consisting of the complex borides (Cr,Fe)хBy is formed during the cladding. The structure provides improving the wear resistance of the steel by 2-5 times. The thickness of the formed layers is 2.5-2.7 mm. The coating formed by beam current 23 mA with Fe as wetting agent has the best set of properties.