Structure and properties of the CoCuTiZrHf coating obtained by the HVOF method

The article is devoted to the comprehensive studies of high-entropy CoCuTiZrHf coating obtained by high-velocity oxygen-fuel (HVOF) in a protective atmosphere. The authors examined the metallophysical properties of the coating (using electron microscopy and X-ray diffraction analysis) in order to obtain new information about its structure, mechanical properties and phase composition. Functional properties were also determined. The authors studied the effect of mechanical activation of highly entropic material powder on the structural phase state and coating quality. The optimal technological parameters of HVOF in a protective atmosphere were determined for the formation of a highly entropic CoCuTiZrHf coating, which provides the highest adhesion and a low porosity. The authors have developed statistical process models with parameter optimisation. On the basis of complex metallophysical studies, the structure formation in highly entropic coatings was researched after HVOF in a protective atmosphere and subsequent heat treatment. Calorimetric tests of the CoCuTiZrHf alloy were performed to identify the exo-effect corresponding to the manifestation of phase transformation. The authors determined what the mechanical properties of coated steel are.