Formation of Coatings Containing Cr2AlC MAX Phase During Plasma Spraying of Mixture of Cr3C2+Al Powders Natalia Vigilianska, Carolina Iantsevitch, Tania Tsymbalista, Oleksii Burlachenko, Oleksandr Grishchenko, et al. Coatings, 2024 In this article, the structure formation and phase composition of coatings containing Cr2AlC MAX phase under the conditions of plasma spraying were studied. Mechanical mixtures of commercially available Cr3C2 and Al powders were used as a material for spraying. The amount of aluminium in the mixtures was 9 and 18 wt.%. As a result of studying physicochemical processes occurring during plasma spraying of mechanical mixtures of selected compositions, the formation of coatings containing Cr2AlC MAX phase was established, the synthesis of which occurs both at the stage of the particles flight of initial components in the plasma jet as a result of the collision and coagulation, and at the stage of a coating layer formation as a result of layering particles deformed during the collision–splats. It is shown that for the formation of a denser coating with a higher MAX phase content for spraying, it is rational to use a mixture of chromium carbide powders with 9 wt.% of aluminium. A coating with the composition 91Cr3C2-9Al (wt.%) has high corrosion resistance in operation conditions in a chloride-acetate solution, and by its indicators of corrosion resistance, is not inferior to the Cr3C2-NiCr coating, which is widely used in industry to protect parts from corrosion and wear. The obtained results show the possibility and feasibility of using mechanical mixtures of commercially available powders for the formation of coatings containing Cr2AlC MAX phase instead of expensive synthesized MAX-Cr2AlC powders.
Changes in Corrosion Behaviour of Zinc and Aluminium Coatings with Increasing Seawater Acidification Cezary Senderowski, Wojciech Rejmer, Nataliia Vigilianska, Arkadiusz Jeznach Materials, 2024 The increase in greenhouse gas emissions has led to seawater acidification, increasing the corrosion rate of metal structures in marine applications. This paper indicates that the spraying of four types of coatings, namely Zn, Al, Zn-Al, and Al-Mg, using the arc-spraying technique on steel substrate S235JR, creates effective protective coatings that interact differently with various pH solutions exposed to varying levels of seawater acidification. The study analyses the structural properties of the coating materials using SEM and XRD techniques. Electrochemical parameters are evaluated in solutions with different pH and salinity levels. The results demonstrate that alloy metallic coatings provide excellent resistance to corrosion in low-pH solutions.
Cermet Powders Based on TiAl Intermetallic for Thermal Spraying Oleksii Burlachenko, Nataliia Vigilianska, Cezary Senderowski Materials Science Forum, 2024 The paper presents a study of the formation process of cermet powders based on TiAl intermetallic with the addition of non-metallic refractory compounds. Non-metallic refractory compounds B4C, BN, SiC, and Si3N4 were chosen as strengthening components, improving the mechanical properties and resistance to high-temperature oxidation of TiAl-type intermetallic coatings. The composition of the initial mixtures was selected based on thermodynamic analysis of the interaction between TiAl intermetallic and non-metallic refractory compounds. As a result of the mechanochemical synthesis of powder mixtures, 73TiAl-27B4C, 69TiAl-31BN, 88TiAl-12SiC, and 83TiAl-17Si3N4 (wt. %) cermet powders are formed, consisting of titanium aluminide (TiAl, Ti3Al) phases and refractory compounds of aluminium (AlB2 and AlN) and titanium (TiB2, TiC, TiN, Ti5Si3). The conglomeration technology of produced cermet powders has been developed to enhance fluidity. Using conglomerated powders will provide their constant feed to the high-temperature jet and the formation of dense coatings during thermal spraying.
Effect of APS Spraying Parameters on the Microstructure Formation of Fe3Al Intermetallics Coatings Using Mechanochemically Synthesized Nanocrystalline Fe-Al Powders Cezary Senderowski, Nataliia Vigilianska, Oleksii Burlachenko, Oleksandr Grishchenko, Anatolii Murashov, et al. Materials, 2023 The present paper presents a study of the behaviour of Fe3Al intermetallic powders particles based on 86Fe-14Al, 86Fe-14(Fe5Mg), and 60.8Fe-39.2(Ti37.5Al) compositions obtained by mechanochemical synthesis at successive stages of the plasma spraying process: during transfer in the volume of the gas stream and deformation at the moment of impact on the substrate. The effect of the change in current on the size of powder particles during their transfer through the high-temperature stream and the degree of particle deformation upon impact with the substrate was determined. It was found that during transfer through the plasma jet, there was an increase in the average size of sputtering products by two–three times compared to the initial effects of mechanochemical synthesis due to the coagulation of some particles. In this case, an increase in current from 400 to 500 A led to a growth in average particle size by 14–47% due to the partial evaporation of fine particles with an increase in their heating degree. An increase in current also led to a 5–10% growth in particle deformation degree upon impact on the substrate due to the rising temperature and velocity of the plasma jet. Based on the research, the parameters of plasma spraying of mechanically synthesized Fe3Al intermetallic-based powders were determined, at which dense coatings with a thin-lamellar structure were formed.
Development of electric-arc pseudoalloy coatings for the strengthening of copper walls of molds Yuri Borisov, Nataliia Vigilianska, Ivan Demianov, Oleksandr Grishchenko Eastern European Journal of Enterprise Technologies, 2018 On the basis of the requirements for protective coatings of molds, the materials of pseudoalloys were determined for applying coatings from two wires. One of the wires is copper, which provides maintaining a sufficient thermal conductivity of the layer, and the second one consists of a material, which provides wear resistance of a coating. As the second wire, the wires NiCr, Mo, Ti and a flux-cored wire were used, consisting of a steel sheath and a filler – FeB powder. Based on the calculation data on the thermal conductivity of coatings, taking into account the coefficients of heat transfer, the estimation of the influence of these coatings on the thermal processes in the mold (temperature of the wall surface, intensity of heat removal from the wall) was performed. Applying electric-arc spraying, the pseudoalloy coatings with a uniform distribution of components were produced, one of which is copper with a hardness of 1,320–1,460 MPa, and the second one is the strengthening component NiCr, with a hardness of 2,440 MPa; Mo, with a hardness of 5,350 MPa; Ti, with a hardness of 7,540 MPa; FeB, with a hardness of 7,050 MPa. As a result of measurements of the coefficient of thermal expansion of coatings, it was found that the coating Cu-NiCr is the closest to the coefficient of thermal expansion of copper. Then it is followed by Cu-FCW (FeB), Cu-Ti and Cu-Mo. The abrasive wear resistance of pseudoalloy coatings at a room temperature exceeds pure copper 1.4–2.3 times. The tests of pseudoalloy coatings for resistance to wear during heating to 350 °C showed that the wear resistance of Cu-NiCr and Cu-FCW (FeB) coatings exceeds the resistance of pure copper 4.5 and 22 times, respectively. The hot hardness of the coating Cu-NiCr in the range of 20–400 °C exceeds the hardness of pure copper 3 times.
