## 3 Results  
With the presence of obstacles in the way of the gas flow, alternations in the character of the gas flow may happen, depending on the shape of the obstacle, characteristics of the flow, etc. It was assumed that similar phenomena occur when atomizing gas flows around the electrodes' butts, after which altered stream characteristics could be initiated in the areas. The ANSYS CFX simulation of an electrode airflow is presented in Figure 3, showing that the zone of depression appears in the flow just behind the electrode. When analyzing the pressure distribution along the axial line, it was found that the highest-pressure value corresponds to the nozzle edge being 0.56 MPa, remaining at this level at a distance of 15 mm from the nozzle's edge with further decreasing to 0.4 MPa. The airflow velocity there was equal to 310-350 m/s. Moving around a solid body (the electrode imitation) placed at a distance of 40 mm from the nozzle's edge, the airflow's pressure and velocity drastically dropped to 0.01 MPa and 30 m/sec accordingly, indicating a depression zone presence with a low oxygen concentration. In practice, the electrode metal is melted exactly within this zone, undergoing less oxidation. The simulated area of depression behind the electrode at EAS was further experimentally revealed by investigating the influence of two crossed electrodes upon the atomizing airflow (without arc initiating). The results of experimental fixation of the airflow are represented in Figure 4 in the form of the gas-spectrograms obtained by \"shadow\" photographing. As seen in the spectrograms, the presence of two electrodes crossed at an angle of 30 degrees with a gap of 2 mm leads to the formation of a depression zone at the electrode's edges. With the aim of confining such airflow behavior, the gas spectrograms were obtained directly under electric arc spraying. The obtained images (Figure 5) show that the shape of the arc discharge at the \"side view\" is close to the shape of the atomizing flow when it passes the edges of electrodes (Figure 4). The light s  
Figure 3: The model of the airflow around a solid body (electrode) at arc metallization: 1—the section with the highest pressure on the edge of the nozzle; 2—a solid body (mitator of an electrode at arc metallization); 3—the section with the highest pressure drop (depression section); 4—airflow; 5—the section where the airflow becomes dense. is smaller than in the peripheral sections, possibly because of the flow's heterogeneity and the presence of pressure drop in the center (Figure 5a). The presented gas-spectrograms allowed concluding that the arc discharge is placed within the zone of reduced pressure. It can also be seen in the \"side view\" that metallic molten particles that are present at the electrode's edges form two streams, imitating the shape of the atomizing gas flow. The \"top view\" images of the electrodes, previously taken by other researchers, could not allow tracking the particle's formation beyond the electrodes that happens under EAS. The performed investigations showed that between the electrodes, there was an area of stable functioning of the arc discharge in which the atomized metal was subjected to lesser oxidation. The obtained results were the basis for further investigation of the perceptiveness of the atomizing air flow pulsation under the EAS process. Figure 6 presents the gas spectrograms for the case of EAS with pulsating airflow. Their analysis shows that all flow sections are in a vibrating motion relative to the flow geometrical axis. The pulsating flow has a \"barrel-like\" wave structure with \"saw-like\" pressure spreading along the flow axis. In the nozzle cross-section, a depression area appears in the shape of a centered wave. The pulsating flow behavior behind the electrode significantly varied depending on the parameters of the non-stationary flow, such as Reynolds number, Mach number, the frequency, and the relative amplitude of the flow pulsations.