The Paton Welding Journal, 2013, №06



2013 №06 (02)

2013 №06 (04)

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The Paton Welding Journal, 2013, #6, 15-22 pages  

GASOABRASIVE WEAR RESISTANCE AT ELEVATED TEMPERATURES OF COATINGS PRODUCED BY THERMAL SPRAYING

V.I. POKHMURSKY¹, M.M. STUDENT¹, A.V. POKHMURSKAYA², I.A. RYABTSEV³, V.M. GVOZDETSKY¹ and T.R. STUPNITSKY¹

¹H.V. Karpenko Physico-Mechanical Institute, NASU, Lvov, Ukraine. E-mail: pokhmurs@ipm.lviv.ua
²ChemnitzUniversity of Technology, Institute of Composite Materials and Surface Technology, Chemnitz, Germany. E-mail: hanna.pokhmurska@mb.tu-chemnitz.de
³E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Thermal spraying is becoming ever wider accepted to produce reconditioning and protective coatings for various functional purposes. However, service life of such coatings has not been studied well-enough so far. This work is a study of the mechanism of formation of electric arc sprayed coatings from flux-cored wires of Fe-Cr-B-Al alloying system. It is found that gasoabrasive wear resistance of coatings from flux-cored wires depends on coating hardness, stresses of the first kind in the coating and on composition of oxide films, which form at spraying and at elevated temperatures during gasoabrasive wear testing. Oxide films initially form on the drop surface during spraying. In addition, in air the porous electric arc sprayed coatings are found to have oxidation on the surface and inside the coating (interlamellar oxidation) and oxidation on the boundary between the coating and steel base. It is shown that the high resistance to gasoabrasive wear is observed in coating, in which tensile stresses are transformed into compressive stresses as a result of the process of inner interlamellar oxidation during isothermal soaking at testing temperature of 400-600 °C, leading to increase of coating volume and improvement of its cohesion strength as a result of its reinforcement by interlamellar films of 100-150 nm thickness. Optimum content of alloying elements and their influence on gasoabrasive wear resistance of coatings are determined. Positive influence of residual compressive stresses in the coatings on gasoabrasive wear is shown. Proposed coatings will become applied in power engineering enterprises. 13 Ref., 1 Table, 12 Figures.
 
 
Keywords: thermal spraying, coatings, flux-cored wires, gasoabrasive wear
 
 
Received:                24.01.13
Published:               28.06.13
 
 
References
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