In-situ TiB2 and Fe2Ti intermetallic assisted hard coatings by Fe-Ti-B based hardfacing electrodes

Abstract

The aim of this study was to form Fe2Ti and TiB2 phases on the steel surface in-situ using ferroalloy starting materials and to investigate the changes in the surface properties such as microstructural, hardness, wear and corrosion behavior. To this end, Fe(18-X)TiXB2 (x = 3-5) based hardfacing electrodes were produced and coated on AISI 1010 steel substrate using electric arc welding method. The development of the substrate coating interface, solidification behavior and microstructural conditions of the samples were examined using a variety of characterization methods. In the coating microstructures, intermetallic phases such as TiB2 and Fe2Ti, alpha-Fe + Fe2Ti eutectic structure and trace amounts of non-equilibrium phases were detected. It has been understood that these phases formed in the microstructure have important effects on the hardness, wear and corrosion resistance of the coating. In the hardness test performed by nanoindentation method, very high hardnesses such as 3254 (+/- 26) HV in TiB2 phase and 1130.1 (+/- 13) HV in Fe2Ti phase were measured. As a result of the ball on disc reciprocal wear test performed against Al2O3 ball at different loads, it has been observed that titanium has an effect on the friction coefficient, and the wear resistance increases with the increasing amount of titanium in the electrode cover composition. In addition, according to the potentiodynamic polarization test results carried out in 3.5% NaCl solution, it has been determined that the corrosion potential increased with increasing titanium in the electrode cover composition, there was no linear change detected in the current density. (C) 2021 Elsevier B.V. All rights reserved.