FORMATION OF THE STRUCTURE, PHASE COMPOSITION AND PROPERTIES OF ELECTRIC EXPLOSIVE WEAR-RESISTANT COATINGS AFTER ELECTRON-BEAM TREATMENT

In the present work, coatings of TiC – Mo, TiC – Ni, TiB2  – Mo, and TiB2  – Ni systems were applied to the surface of Hardox 450 steel by the method of electrospray coating. After that, the electron-beam treatment of the coatings was carried out. It was established that after electro-explosive spraying of the coatings of the systems under investigation, a number of morphological features of the relief are formed on the surface: deformed crystallized microglobules, incrustations, microcraters, microcracks, layers. After the electron-beam treatment of the coatings, microglobules, microcraters and microcracks disappear on their surfaces, a polycrystalline structure is formed, in the bulk of which the structure of cellular crystallization is observed. The roughness of the coatings after electron beam treatment is 1.1  –  1.2  μm. It  was also established that the thickness of the layers of electrically explosive coatings modified by an electron beam, depending on the surface energy density, is linear. Its maximum value is observed for the TiB2  – Mo system, the minimum – for the TiC – Ni system, which is explained by their thermophysical properties. In the coatings the following substructures are revealed: cellular, strip, fragmented, subgrain, and also grains with chaotically distributed dislocations and dislocations that form grids. Electron beam treatment of coatings leads to the formation of a composite filled structure throughout the entire section of the remelted layer, forming a more dispersed and homogeneous structure in it than in coatings without electron beam treatment. Dimensions of inclusions of titanium carbide or titanium diboride in molybdenum or nickel matrix are reduced by a factor of 2  –  4 compared with their dimensions immediately after electrospray deposition. Particles of the second phases are found in the volume of molybdenum or nickel grains and at the boundaries: titanium carbide or titanium diboride. They have a rounded shape and can be divided into two classes in size: 1. particles of initial powders with dimensions of 80  –  150  nm, not dissolved in the irradiation process; 2. particles released during crystallization of the melt with dimensions of 10  –  15  nm. The basis of the structure formation in electric explosive powder coatings is the dynamic rotation of the sputtered particles, which form a vortex structure both in the coating and in the upper layers of the substrate. Formed coatings have increased performance properties: nano- and microhardness, a modulus of elasticity of the first kind and wear resistance in conditions of dry sliding friction. 

1. Vopneruk A.A., Valiev R.M., Vedishchev Yu.G., Shak A.V., Kuptsov  S.G., Fominykh M.V., Mukhinov D.V., Ivanov A.V. Abrasive wear resistance of coatings applied by the method of high-speed flame spraying. Izvestiya Samarskogo nauchnogo tsentra RAN. 2010, vol. 12, no. 1 (2), pp. 317–320. (In Russ.).

2. Ibragimov A.R., Ilinkova T.A., Shafigullin L.N., Saifutdinov A.I. Investigation of mechanical properties of thermal coatings obtained during plasma spraying of powder zirconium dioxide. IOP Conference Series: Journal of Physics: Conf. Series. 2017, vol. 789, pp.  012022.

3. Savkova J., Houdková Š., Kašparová M. High temperature tribological properties of the HVOF sprayed TiC-based coatings. Metal. 2012, vol. 25, no. 5.

4. Xiaoqian G., Yaran N., Liping H., Heng J., Xuebin Z. Microstructure and tribological property of TiC-Mo coating prepared by vacuum plazma spraying. Journal of Termal Spray Technology. 2012, vol. 21, no. 5, pp. 1083–1089.

5. Da Cunha C.A., de Lima N.B., Martinelli J.R., de Almeida Bressiani A.H., Fernando Padial A.G., Ramanathan L.V. Microstructure and mechanical properties of thermal sprayed nanostructured Cr3 C2 –Ni20Cr coatings. Materials Research. 2008, vol. 11, no. 2, pp.  137–143.

6. Serek A., Budniok A. Electrodeposition and thermal treatment of nickel layers containing titanium. Journal of Alloys and Compounds. 2003, vol. 352, no. 1-2, pp. 290–295.

7. Panek J., Budniok A. Production and electrochemical characterization of Ni-based composite coatings containing titanium, vanadium or molybdenum powders. Surface and Coatings Technology. 2007, vol. 201, no. 14, pp. 6478–6483.

8. Strzeciwilk D., Wokulski Z., Tkacz P. Microstructure of TiC crystals obtained from high temperature nickel solution. Journal of Alloys and Compounds. 2003, vol. 350, no. 1-2, pp. 256–263.

9. Arya A., Dey G.K., Vasudevan V.K. et al. Effect of chromium addition on the ordering behaviour of Ni-Mo alloy: experimental results vs. electronic structure calculations. Acta Materialia. 2002, vol. 50, no. 13, pp. 3301–3315.

10. Lemster K., Graule T., Kuebler J. Processing and microstructure of metal matrix composites prepared by pressureless Ti-activated infiltration using Fe-base and Ni-base alloys. Materials Science and Engineering: A. 2005, vol. 393, no. 1-2, pp. 229–238.

11. ZhaoY.,Jiang C., Xu Z., Cai F., Zhang Z., Fu P. Microstructure and corrosion behavior ofTi nanoparticlesreinforced Ni–Ti composite coatings by electrodeposition. Materials & Design. 2015, vol. 85, pp.  39–46.

12. Chang C.H., Jeng M.C., Su C.Y., Huang T.S. A study of wear and corrosion resistance of arc-sprayed Ni-Ti composite coatings. Journal of Thermal Spray Technology. 2011, vol. 20, no. 6, pp. 1278–1285.

13. Surzhenkov A., Antonov M., Goljandin D., Vilgo T., Mikli V., Viljus  M., Latokartano J., Kulu P. Sliding wear of TiC-NiMo and Cr3 C2 -Ni cermet particles reinforced FeCrSiB matrix HVOF sprayed coatings. Estonian Journal of Engineering. 2013, vol. 19, no. 3, pp. 203–211.

14. Surzhenkov A., Antonov M., Goljandin D., Kulu P., Viljus M., Traksmaa R., Mere A. High-temperature erosion of Fe-based coatings reinforced with cermet particles. Journal Surface Engineering. 2016, vol. 32, no. 8, pp. 624–630.

15. Nikolenko S.V., Syui N.A., Burkov A.A. Investigation of microstructure and properties of coatings on steel 45 deposited by electrospark deposition by TiC-Ni-Mo electrodes. Tsvetnye metally. 2017, no. 4, pp. 69–75. (In Russ.).

16. Romanov D.A., Goncharova E.N., Budovskikh E.A., Gromov  V.E., Ivanov Yu.F., Teresov A.D. Elemental and phase composition of TiB2 –Mo coating sprayed on a steel by electro-explosive method. Inorganic Materials: Applied Research. 2017. vol. 8, no.  3, pp.   23–427.

17. Romanov D.A., Goncharova E.N., Budovskikh E.A. et al. Structure of electroexplosive TiC – Ni composite coatings on steel after electron-beam treatment. Russian Metallurgy (Metally). 2016, no.  11, pp. 1064–1071.

18. Romanov D.A., Goncharova E.N., Budovskikh E.A., Gromov V.E., Ivanov Yu. F., Teresov A.D. Structure of electroexplosive TiB2 – Ni composite coatings after electron beam processing. Inorganic Materials: Applied Research. 2015, vol. 6, no. 5, pp. 536–541.

19. Romanov D.A., Olesyuk O.V., Budovskikh E.A., Gromov V.E. Sposob elektrovzryvnogo napyleniya kompozitsionnykh iznosostoikikh pokrytii sistemy TiC-Mo na poverkhnosti treniya [Method of electrospray spraying of composite wear-resistant coatings of the TiCMo system on friction surface]. Patent no. 2518037 RF. Byulletenʹ izobretenii. 2014, no. 16. (In Russ.).

20. Koval’ N.N., Ivanov Yu.F. Nanostructuring of surface of cermet and ceramic materials under pulsed electron beam treatment. Izvestiya vuzov. Fizika. 2008, no. 5, pp. 60–70. (In. Russ.).