Mechanical and tribological properties of Ti1-xZrxB2 coatings deposited by magnetron sputtering on hot work steel

Abstract

AbstractLow fracture toughness is a common problem encountered by many researchers in the application of pure TiB2 coatings. To improve their properties, a convenient and useful method is the use of doping, so this study proposes the deposition of TiB2 enriched with Zr on a steel substrate. The objective of the research was to investigate the impact of Zr addition to TiB2 coatings on both their mechanical and tribological properties. Four coatings with varying compositions (pure TiB2; TiB2 doped with 3, 6, and 10 at.% Zr) were deposited using magnetron sputtering from TiB2 and Zr targets. The coating structures were analyzed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Nanoindentation, scratch test, and ball-on-disk test were used to determine the mechanical and tribological properties. In most cases, only two factors have a significant impact on the mechanical and tribological properties of the Zr-doped coating. Firstly, a change in the preferred orientation of the coating from (102)(111) to (100) results in increased hardness and wear resistance. Secondly, a reduction in crystallite and column size enhances ductility and fracture toughness by impeding or altering the direction of crack propagation. Based on the study, one can conclude that the optimal Ti1-xZrxB2 properties were obtained for 6 at.% Zr content.