УДК 621.162 Ewa Kasprzycka, Bogdan Bogdański PROPERTIES OF THE CrC+(Ni-Mo) DUPLEX LAYERS PRODUCED IN VACUUM CHROMIZING PROCESS TOGETHER WITH GALVANIC TREATMENT Vacuum chromizing of tool steel results in hard and wear resistant coatings based on chromium carbide. <...> However, the received carbide layers exhibited rather poor corrosion resistance in chloride media. <...> To improve their corrosion resistance Ni-Mo alloy was deposited electrolytically on the steel surface before the chromizing process. <...> This resulted in the formation of CrC+(Ni-Mo) type duplex layers with modified characteristics. <...> The objective of this paper was to determine the corrosion resistance in chloride solution of such duplex layers produced on tool steel surface, as well as their tribological properties. <...> It has been proved, that the wear resistance by friction of duplex layers of the CrC+(NiMo) type, produced by means vacuum chromizing of steel covered with electrolytic coating, is such good as carbides layers of the CrC type, produced on the steel surface without electrolytic coating, but their corrosion resistance is several times higher. <...> Keywords: chromium carbide layers, thermochemical treatment, electrolytic deposition, vacuum chromizing, corrosion/wear resistance. 1. <...> It is possible to produce, by means of this process, hard and wear resistant chromium carbide layers on tool steel surface. <...> In the Institute of Precision Mechanics chromizing method was developed, which consists in holding steel at the temperature over 1000 o C in chromium vapour under low pressure conditions [3, 4]. <...> However, the received carbide layers exhibited rather poor corrosion resistance in chloride media [4-7]. <...> Layer microstructure was revealed by nital etching. <...> Tribological properties of the layers were evaluated by sliding wear tests with concentrated contact. <...> The objective of this paper was to determine the tribological properties of such duplex layers produced on tool steel surface, as well as their corrosion resistance in chloride solution. 2. <...> EXPERIMENTAL The chromizing processes were carried out in a cold-wall vacuum oven at the temperature range of 1100-1150 o 10-3 C at the pressure ranged from 10 Pa down to Pa. Experiments were carried out on samples made <...>