УДК 621.162 Ewa Kasprzycka, Andrzej Kr likowski ANTICORROSION PROTECTIVENESS OF DUPLEX LAYERS PRODUCED BY VACUUM TITANIZING PROCESS COMBINED WITH THE ELECTROLYTIC DEPOSITION OF Co-W ALLOY Duplex titanized layers were obtained by electrolytic deposition of Co-W alloy on tool steel surface and subsequent diffusion titanizing process. <...> Structural studies of these layers were performed by metallographic microscopy, X-ray diffraction and SEM observation combined with electron microprobe analysis. <...> The duplex layers of TiC+(Co-W) type showed zonal structure and higher thickness than titanized (TiC type) layers prepared directly on tool steel. <...> Wear resistance of tested samples was determined by sliding test and corrosion measurements were performed in 0.1 H2 solution by means of potentiodynamic polarization and electrochemical impedance. <...> It has been proved that the anticorrosion protectiveness of the TiC+(Co-W) duplex layers is higher then that for the TiC titanized carbide layers. <...> Moreover, the wear resistance of these duplex layers was superior. <...> Keywords: titanium carbide layers, thermochemical treatment, electrolytic deposition, vacuum titanizing, corrosion/ wear resistance. <...> INTRODUCTION Diffusion titanizing is one of many types of thermochemical treatment used mainly to improve the hardness and wear resistance of steel surfaces. <...> Titanizing of high carbon steel results in hard and wear resistant coatings based on titanium carbide [1 3]. <...> In the Institute of Precision Mechanics titanizing method was developed, which consists in holding steel at the temperature over in titanium vapour under low pressure conditions [4]. <...> However, the received carbide coatings exhibited rather poor corrosion resistance in acid media. <...> To improve the corrosion resistance, Co-W alloy was deposited electrolytically on the steel surface before the titanizing process. <...> The objective of this paper was to determine the corrosion resistance in acid solution of such duplex layers produced on tool steel surface, as well as their tribological properties in relation to structural characteristics. <...> EXPERIMENTAL The titanizing processes were carried out in a coldwall vacuum oven at the temperature range of 1050 1100°C at the pressure ranged from 10 Pa down to Pa. Experiments were carried out on samples made of X210Cr12 tool steel. <...> Duplex <...>