When using double-wire arc spraying, strong dependencies between the process parameters and the layer characteristics can usually be determined. The aim of this article is to investigate the behavior of steel particles during flight depending on the input parameters of the spray gun to show how the particle characteristics affect the layer properties. The measurements of the "in-flight" particles are carried out with the aid of the DPV 2000 diagnostic system. The system allows the simultaneous measurement of speed, temperature, and particle size. Due to the direct dependence of the particle size distribution on the spraying parameters, a test stand is developed to capture particles at the spraying distance while taking into account the arrangement of the DVP 2000 measuring volume. Finally, the relationship between the spray parameters, the characteristics of the "in-flight" particles and the layer properties is worked out. Paper includes a German-language abstract.