Abstract
This research work studies the characteristics of wear and wear resistance of composite powder coatings, deposited by supersonic flame jet (HVOF), which contain composite mixtures Ni-Cr-B-Si having different chromium concentrations—9.9%, 13.2%, 14%, 16%, and 20%, at one and the same size of the particles and the same content of the remaining elements. The coating of 20% Cr does not contain B and Si. Out of each powder composite, coatings have been prepared without any preliminary thermal treatment of the substrate and with preliminary thermal treatment of the substrate up to 650 °C. The coatings have been tested under identical conditions of dry friction over a surface of solid, firmly-attached, abrasive particles using tribological testing device “Pin-on-disk”. Results have been obtained and the dependences of the hardness, mass wear, intensity of the wearing process, and absolute and relative wear resistance on the Cr concentration under identical conditions of friction. It has been found out that for all the coatings the preliminary thermal treatment of the substrate leads to a decrease in the wear intensity. Upon increasing Cr concentration the wear intensity diminishes and it reaches minimal values at 16% Cr. In the case of coatings having 20% Cr concentration, the wear intensity is increased, which is due to the absence of the components B and Si in the composite mixture, whereupon no inter-metallic structures are formed having high hardness and wear resistance. The obtained results have no analogues in the current literature and they have not been published by the authors.
Highlights
The basic priorities of contemporary engineering science and practice refer to enhancement of energy effectiveness and functionality of the industrial systems in harmonic coexistence with clean environment, preservation of natural resources, and improving of the quality of life
The lowering of the wear intensity in the machines appears to be the central task of tribology tribological technologies
The problem of abrasive and erosive wear resistance of tribological materials is of exceptional importance and actuality, which is evidenced by the fact that there exist active standards ASTM, concerning the abrasive wear and at least 4 standards connected with the erosion wear
Summary
The basic priorities of contemporary engineering science and practice refer to enhancement of energy effectiveness and functionality of the industrial systems in harmonic coexistence with clean environment, preservation of natural resources, and improving of the quality of life. The composite powder coatings, deposited by means of supersonic flame jet-HVOF (High Velocity Oxy-Fuel) are a new generation of tribo-materials, allowing to achieve a wide range of combining mechanical and tribological characteristics—high adhesion strength, density, hardness, wear resistance, and corrosion stability. In the paper [40], the influence of the dimensions of the abrasive particles has been presented on the abrasive stability on the coatings of 40WC/Co, applied by three technological regimes: high velocity oxygen fuel (HVOF), high energy plasma spray (HEPS), and high velocity plasma spray (HVPS) with the use of nanostructured experimental powders. By meansThe of present supersonic flamerepresents jet on a the substrate withanand withoutabout thermal treatment of th publication results from investigation the influence of chromium concentration on the abrasion wear of Ni-Cr-B-Si coatings, deposited by substrate. Means of supersonic flame jet on a substrate with and without thermal treatment of the substrate
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