Electric arc spraying of coatings is common in many branches of industrial production, in particular to restore the geometry of machine parts worn in operational conditions, to increase their protection against abrasive and gas-abrasive wear (at the same time, both at climatic and at technologically determined elevated temperatures). Coatings sprayed using powdered wires are characterized by high chemical heterogeneity, which significantly distinguishes them from electric arc coatings made of solid wires. This is due to the different chemical composition of the droplets formed from the molten powder wires and carried by the air jet to the surface of the substrate, forming a coating on it. The charge with alloying elements in its composition (including difficult-to-melt ones such as FH, B4C, FHB) does not have time to fully melt and mix with the melt of the steel shell. It is clear that because of this, the melt droplets of flux-cored wires dispersed by an air jet will have a different chemical composition and , as a result, the coatings formed from these droplets on the surface of the substrate will be characterized by high heterogeneity and significant chemical heterogeneity, which will affect their physical and mechanical properties at different operating temperatures and especially when exposed to corrosive environments. To ensure high corrosion resistance of electric arc coatings in aggressive environments, it was necessary to reduce their chemical microheterogeneity and achieve a sufficiently high chromium content (it should be more than 12 wt.%) in each of its lamellae. To achieve this goal, ingredients were added to the composition of the charge, which enabled the formation of eutectics with a low melting temperature, with the dissolution of such refractory components of the powder wire charge as carbides, borides, refractory metals and alloys. Microhardness measurements showed that the highest hardness was achieved by electric arc coatings made of powder-coated wires №. 2 (20X16Р3Н2ГС) and powder-coated wires №. 5 (Х17Р3С). This happened due to the presence in the charge of 3 wt.% of boron, which entered their charge as part of the FHB-2 ferrochromiumboron powder. Phase analysis of these EDPs revealed the segregation of finely dispersed FeCrB and FeCr2B borides in their ferrite structure. However, the cohesive strength of these coatings did not exceed 100 MPa. This was explained by the fact that during filing, residual first-order tensile stresses could occur in their structure, which, as a rule, contribute to the cracking of the coatings during their subsequent mechanical processing. Therefore, before applying coatings from such powdered wires, the base for spraying should be heated to 150...200ºС. Conclusions. 1. To ensure complete fusion of the components of the powder-coated wire charge with each other and with its steel sheath, it is proposed to add Fe-Mn, Fe-Si ferroalloy powders to the powder-coated wire charge, which are able to interact with the refractory components of the charge with the formation of low-temperature eutectics. The legality of such a component composition of the charge of flux-cored wires as an effective method of reducing the melting temperature of the components has been experimentally substantiated. 2. The addition of ferrosilicon, ferromanganese powders and self-fluxing alloy PН-10Н-01 to the charge of flux-cored wires based on ferrochromium and ferrochromium ensured high hardness of electric arc coatings, low heterogeneity of the chromium content in the lamellae, and, as a result, high corrosion resistance, which comparable to that of stainless steel

coating, powder wires, microheterogeneity, microhardness, corrosion resistance

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1. Student, M.M., Markovych, S.I., Hvozdetskyi, V.М., Kalakhan, О.S., Yuskiv, V.M. (2022) Abrasive Wear Resistance and Tribological Characteristics of Electrometallized Composite Coatings. Materials Science, 58(1), 96–104 [in English].

2. Pokhmurs’ka H.V., Holovchuk M. Ya., Dz’oba Yu. V., Hvozdets’kyi V. М., Dzyubyk L. V. (2018). Influence of the composition of charge of powder wires on the structure and properties of electric-arc coatings. Materials Science, Vol.53, 6, 868–874 [in English].

3. Stupnyts’kyi, T.R., Student, M.M., Pokhmurs’ka, H.V., Hvozdets’kyi, V.M. (2016). Optimization of the Chromium Content of Powder Wires of the Fe–Cr–C and Fe–Cr–B Systems According to the Corrosion Resistance of Electric-Arc Coatings. Materials Science, 52(2), 165–172 [in English].

4. Student, M.M., Holovchuk, M.Ya. & Hvozdets'kyj, V.M. (2017). Vplyv khimichnoho skladu poroshkovykh drotiv na strukturu ta znosostijkist' pokryttiv riznoho khimichnoho skladu [Influence of chemical composition of flux-cored wires on the structure and wear resistance of coatings of different chemical composition]. Problemy trybolohii – Problems of tribology, 3, 56-61 [in Ukrainian].

5. Korobov, Yury. (2018). Arc-Sprayed Fe-Based Coatings from Cored Wires for Wear and Corrosion Protection in Power Engineering Coatings, 8(2), 71 [in English].

6. Borisova, A.L., Mitz, I.V., Kaida, T.V. et al. (1991).The structure and properties of electric arc coatings based on ferroboron obtained from powder wires. Automatic welding, 9, 66–68 [in English].

7. Dallaire, S. & Levert, H. (1992). Synthesis and deposition of TiB2 containing materials by arc spraying. Surface and Coatings Technology, 50, 2, 241–248 [in English].

8. Ana Arizmendi-Morquecho, Araceli Campa-Castilla, C. Leyva-Porras, Josué Almicar Aguilar Martinez, Gregorio Vargas Gutiérrez, Karla Judith Moreno Bello, L. López López. (2014). Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying. Advances in Materials Science and Engineering. Vol. 2014. Article ID 836739 https://doi.org/10.1155/2014/836739 [in English].

1. Abrasive Wear Resistance and Tribological Characteristics of Electrometallized Composite Coatings / M.M.Student, S.I. Markovych, V.М. Hvozdetskyi, О.S. Kalakhan, V.M. Yuskiv. Materials Science, 2022, Vol.58(1), pp. 96–104.

2. Influence of the composition of charge of powder wires on the structure and properties of electric-arc coatings / H.V. Pokhmurs’ka, M.Ya. Holovchuk, Yu.V. Dz’oba, V.М. Hvozdets’kyi, L.V. Dzyubyk. Materials Science. 2018. Vol.53, №6. Р. 868–874.

3. Optimization of the Chromium Content of Powder Wires of the Fe–Cr–C and Fe–Cr–B Systems According to the Corrosion Resistance of Electric-Arc Coatings / T.R. Stupnyts’kyi, M.M. Student, H.V. Pokhmurs’ka, V.M. Hvozdets’kyi, Materials Science, 2016, Vol. 52(2), pp. 165–172.

4. Студент М.М., Головчук М.Я., Гвоздецький В.М. Вплив хімічного складу порошкових дротів на структуру та зносостійкість покриттів різного хімічного складу. Проблеми трибології. 2017. № 3. С. 56-61.

5. Arc-Sprayed Fe-Based Coatings from Cored Wires for Wear and Corrosion Protection in Power Engineering Korobov Yury. Coatings. 2018. Vol.8(2). 71 p.

6. The structure and properties of electric arc coatings based on ferroboron obtained from powder wires / AL Borisova, IV Mitz, TV Kaida [et al.]. Automatic welding. 1991. 9. P. 66–68.

7. Dallaire S., Levert H. Synthesis and deposition of TiB2 containing materials by arc spraying. Surface and Coatings Technology. 1992. 50, 2 . P. 241–248.

8. Microstructural Characterization and Wear Properties of Fe-Based Amorphous-Crystalline Coating Deposited by Twin Wire Arc Spraying / Ana Arizmendi-Morquecho, Araceli Campa-Castilla, C. Leyva-Porras, Josué Almicar Aguilar Martinez, Gregorio Vargas Gutiérrez, Karla Judith Moreno Bello, L. López López. Advances in Materials Science and Engineering. 2014. Vol. 2014. Article ID 836739 https://doi.org/10.1155/2014/836739.

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