Wear-Resistance of Detonation-Sprayed Cr-Si-B Coatings under Friction at Elevated Temperatures

Abstract

The friction and wear of detonation-sprayed Cr–Si–B coatings in high-temperature friction conditions are studied. The choice of Cr–Si–B composition and its optimal content for spraying of wear-resistant coatings subjected to friction under high-temperature conditions are justified. It is noted that alloying elements at certain concentrations and spraying parameters have positive influence on the structure and properties of multicomponent coatings. It is shown that the introduction of silicon and boron promote the formation of hard-alloy high-temperature compounds with increased wear resistance. The maximum microhardness corresponds to the Cr–Si coatings with ~25% silicon content. Besides, the mechanical properties of the material are improved by additional alloying with ~12% boron. In turn, the coatings deposited at a gas expense of acetylene and oxygen, corresponding to the value ~22/27 l/min provides constant spraying parameters, unchanged chemical composition, and stable properties of the coatings. The Cr–Si–B coatings show stable structural adaptability, which minimizes the friction and wear parameters, at 5.0 MPa loading and a sliding speed of 1.5 m/sec and up to 700 °С. Metallographic analysis and strip chart recording of the samples indicate that the friction surfaces are free of visible defects and individual cold-welded regions are located in thin-film surface layers. The composition, structure, and tribological stability of the Cr–Si–B coatings produced from domestic raw materials are examined; they exhibit high adhesion, mechanical characteristics, and wear resistance at elevated temperatures. Modern physical and chemical methods of analysis are used to study the structure and properties of thin-film surface structures. It is determined that combination of mechanical, physical, and chemical properties of the Cr–Si–B coatings provides wide opportunities for their use under high-temperature wear conditions.