Effect of boronizing on microstructure, high-temperature wear and corrosion behavior of additive manufactured Inconel 718

Abstract

In this study, Ni-based Inconel 718 coatings were additively manufactured on the surface of AISI H13 work tool steel by electro-spark deposition (ESD). Some of the electro-spark deposited samples were boronized at 1000 °C for 5 h to evaluate the effects of boronizing on microstructure, high-temperature wear, and corrosion resistance. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), 2D profilometry, wear and electrochemical corrosion testing was used to characterize the surfaces, microstructures, microhardness, some mechanical properties, high-temperature wear, and corrosion resistance of the applied coatings. Wear tests were performed at room temperature and 650 °C, and corrosion tests were performed in 3.5% NaCl at room temperature, considering the applications of AISI H13 and Inconel 718 alloys. The characterization studies showed evidence of microcracking and oxidation in the as-deposited Inconel 178 coatings. In the boronized Inconel 718 coatings, the oxides and microcracks were slightly reduced. The hardness of the boronized Inconel 718 coating was increased to about four times the hardness of the as-deposited Inconel 718 coating, and this significantly improved its wear resistance. The highest wear resistance was achieved with the boronized coating, while the best corrosion resistance was obtained with the as-deposited coating. The improvements in wear resistance provided by boronizing have the potential for expanding the applications of Inconel 718 coatings in machine components. • AISI H13 tool-work steel exposed to combined electro-spark deposition and boronizing processes. • The microstructure, friction, wear and corrosion behaviors of different surfaces were compared and analyzed. • The irregularly shaped oxides and cracks in the ESD coatings were healed and the microstructure was refined by boronizing. • Electrospark deposition and boronizing improved corrosion and high-temperature wear resistance of AISI H13 steel. • Boronizing offers an alternative to laser surface modifications in improving the mechanical properties of ESD coatings.