Investigation of Factors, Determining Dispersity of Coating Particles at Arc Sputtering With Pulsating Spraying Stream

Royanov, Vyacheslav; Zakharova, Irina; Mykyta, Kriuchkov; Chigarev, V. V.

doi:10.31435/rsglobal_ws/30062020/7099

Cited by 2 publications

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“…This can be explained by the effect of the pulsation frequency on the curvature radius of molten metallic droplets forming at the electrode butt (the droplet size is important since it determines the area of liquid metal that contacts with the airflow oxygen). This approach is outlined in [39], where the mass transfer of electrode metal under the airflow pulsation was analyzed, and the conditions of the detachment of molten metal from the electrode were studied. According to [39], the curvature radius of a droplet (R cur ) can be calculated by the equation:…”

Section: Discussionmentioning

confidence: 99%

“…This approach is outlined in [39], where the mass transfer of electrode metal under the airflow pulsation was analyzed, and the conditions of the detachment of molten metal from the electrode were studied. According to [39], the curvature radius of a droplet (R cur ) can be calculated by the equation:…”

Section: Discussionmentioning

confidence: 99%

“…ditions of the detachment of molten metal from the electrode were studied. According to [39], the curvature radius of a droplet (Rcur) can be calculated by the equation: where vel-electrode feeding velocity, f-pulsation frequency, щ-angle between the electrodes, del-diameter of the electrode.…”

Section: Discussionmentioning

confidence: 99%

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Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

2021

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The paper aims to investigate the airflow dynamics of electric-arc spraying (EAS) with airflow pulsation. The study is focused on the dynamic structure of the airflow with an obstacle in the form of crossed electrodes at the steady and the pulsating air supply (with a frequency up to 120 Hz). The work was fulfilled using a computer simulation, the airflow “shadow” photo visualization, and the microstructure characterization of the coatings formed. It was found that when air flows along the crossed electrodes with a gap of 2 mm, a depression zone appears in the flow with a pressure drop from 0.56 MPa to 0.01 MPa. The air pulsation resulted in a change in a flow’s dynamic structure towards an increase in the length of the depression zone, which covers most of the arc, affecting the liquid metal oxidation. It is established that the frequency of a droplet formation should match the frequency of the airflow pulsation to minimize the metal oxidation. With the air pulsating at about 65 Hz, the oxide volume fraction in the aluminum coating was reduced by 3.6 times compared to the steady airflow. EAS with airflow pulsation has the potential for technological cost reduction.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

2021

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“…which takes part in the process of metal spraying using a pulsator, was determined analytically depending on the frequency of pulsations of the air flow for different positions of the pulsator valve (K), for which the expression [26] was used:…”

Section: Principle Of Spray Flow Control In Electric Arc Sprayingmentioning

confidence: 99%

Determination of adhesion of the coating deposited by arc spraying with pulsation of atomizing air flow

Zakharova

2021

EEJET

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During electric arc spraying, during the transfer of molten metal by air flow, there is a significant burnout of alloying elements with the formation of a large amount of oxides, which negatively affects the adhesion of the coating to the base. A solution to the problem of increasing the adhesion strength by using pulsation of the atomizing air flow is proposed. At the optimal frequency of the pulsed flow shut-off, the time of formation of liquid metal droplets at the ends of the electrodes coincides with the frequency of pulses of the spraying flow. As a result, the droplets acquire an optimal size, they are transported by an air flow with conservation of energy, a lower mass of oxygen and, as a consequence, a significant decrease in the oxidation of alloying elements in the sprayed material. The existing test methods of sprayed coatings for adhesion strength to the base are analyzed. The design of a modernized device for determining the adhesion strength is developed and described, which provides complex loading of the coating with a combination of tear-off and shear. The tests revealed a significant (up to two times) increase in the adhesion strength of aluminum, zinc-aluminum and steel (Sv08A) coatings applied with air pulsation. This is achieved by increasing the number of fusion zones of the coating particles between themselves and with the base. It is shown that the effect of the pulsation frequency on the adhesion strength changes along a curve with a maximum corresponding to a frequency of 70–80 Hz, regardless of the coating material. It has been established that the aluminum coating has an increased tendency to oxidation, as a result of which it is 15–20 % inferior to the zinc-aluminum coating in adhesion strength. The data obtained substantiate the use of the proposed spraying technology in production

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Investigation of Factors, Determining Dispersity of Coating Particles at Arc Sputtering With Pulsating Spraying Stream

Cited by 2 publications

References 1 publication

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

Determination of adhesion of the coating deposited by arc spraying with pulsation of atomizing air flow

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