The effect of plasma coatings on the properties of low-alloy steels

The paper considers the possibility of using ion-plasma spraying of coatings on low-alloy steels 4Х5MFS and 5ХNM. The choice of these grades is due to the fact that they do not contain tungsten, given the sharp increase in its deficiency, and the molybdenum content is limited, and these steels also meet the requirements for the substrate material on which the titanium nitride coating is applied. The coatings were applied by the method of condensation of the substance under ion bombardment conditions. To determine the required nitrogen pressure, titanium nitride is applied at different partial nitrogen pressures – from 310 -3 to 1 Pa. Coatings obtained under different nitrogen pressures differ in the amount and size of the droplet phase. The largest amount of the droplet phase containing α-Ti is observed in coatings obtained at nitrogen pressures of 3x10–3 Pa, 3x10–2 Pa. An increase in nitrogen pressure (4·10–1 Pa, 1 Pa) significantly reduces the level of microdistortions of crystal lattices in the coating, its plasticity increases. In this regard, the fragility of the coating decreases with its sufficiently high hardness. As laboratory tests have shown, a titanium nitride coating applied under optimal technological parameters increases the corrosion resistance of the materials on which it is applied three times, and scale resistance – two to four times.