Air-plasma spraying of cavitation- and hydroabrasive-resistant coatings
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DOI: 10.1134/S0869864320020109
Air-plasma spraying of cavitationand hydroabrasive-resistant coatings* V.I. Kuzmin1, I.P. Gulyaev1, D.V. Sergachev1, S.P. Vashchenko1, B.V. Palagushkin2, A.O. Tokarev2, and M.G. Menzilova2 1
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2
Siberian State University of Water Transport, Novosibirsk, Russia
E-mail: [email protected] (Received August 7, 2019; revised October 28, 2019; accepted for publication November 6, 2019) Results of a study of the air-plasma spraying of cavitation- and hydroabrasive-resistant coatings from powder materials are reported. A method of laboratory (bench) testing of coatings for resistance under pulsed impact loads is proposed. The bench is a laboratory impact tester that strikes an indenter brought in permanent contact with the sample. A measure of the damage inflicted to the surface hardened by a wear-resistant coating is the diameter of the hole produced by the indenter. The moment of coating destruction is the time at which cracks appear in the coating or the peeling occurs. The developed technique of the bench tests for the pulsed impact loading of wear-resistant coatings imitates the operating conditions of the blades of a high-speed propeller of a water-jet propulsion device in shallow water. The method of air-plasma spraying of powder materials as protective coatings was successfully tested when hardening the propeller blades of a water-jet propulsor of a KS-101D river ship. Keywords: air-plasma spraying, plasma torch with a sectioned interelectrode insert, circular input for powder materials, axisymmetric heterogeneous flow, cavitation and hydroabrasive wear, impact loads, wear-resistant coatings, adhesion, cohesion, porosity.
Introduction Cavitation erosion of propellers was first discovered at the end of the XIX century when testing the ships of the British Navy [1]. The cavitation phenomenon is caused by the formation of air bubbles in water in regions with reduced pressure near the propeller blade surface and their subsequent high-speed implosion (collapse). It turned out that the intense cavitationinduced erosion of propellers reduces their strength characteristics, thus being the main factor to restrict their service life. In addition, the cavitational destruction of the surface of propeller blades leads to a reduction of the propulsive efficiency of propulsors, a decrease in the speed of ships, and a noticeable increase in fuel consumption. When vessels move in shallow water, there additionally arises a problem of hydroabrasive and impact-abrasive wear. In terms of damage intensity, the wear due to the exposure to sand, silt, and gravel particles in a water * This work was carried out within the framework of the Program of Fundamental Scientific Research of the State Academies of Sciences for the years of 2013−2020 (Project No. АААА-А17-117030610120-2).
V.I. Kuzmin, I.P. Gulyaev, D.V. Sergachev, S.P. Vashchenko, B.V. Palagushkin, A.O. Tokarev, and M.G. Menzilova, 2020
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V.I. Kuzmin,
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