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 optimal choice of Cr–Si–B composition for spraying of wear-resistant coatings subjected to friction at high temperatures is justified. It is noted that doping elements in 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 complex doped 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 doping with ~ 12 % boron. In turn, the acetylene–oxygen mixture supplied at 22/27 L/min promotes constant spraying parameters, unchanged chemical composition, and stable properties of the coatings. The Cr–Si–B coatings show appropriate structural adaptability, which minimizes the friction and wear parameters, at 5.0 MPa loading and a sliding speed of 1.5 m/sec up to 700 °C. 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 Cr–Si–B coatings exhibit high adhesion, mechanical characteristics, and wear resistance at elevated temperatures, which correspond to the properties of heat-resistant high alloys. Current physical and chemical analysis methods are employed to study the structure and properties of thin-film surface structures. It is determined that the mechanical, physical, and chemical properties combined in the Cr–Si–B coatings provide wide opportunities for their application in high-temperature wear conditions.