Actual Problems in Machine Building 2020 Vol. 7 No. 1-2

Актуальные проблемы в машиностроении. Том 7. № 1-2. 2020 Материаловедение в машиностроении __________________________________________________________________ 127 AIR PLASMA SPRAYING OF BORON CARBIDE COATINGS Binceva A.A. 1 , Graduate student, e-mail: sashazhoidik@gmail.ru Kornienko E.E. 1 , Ph.D. (Engineering), Associate Professor, e-mail: kornienko_ee@mail.ru Kuzmin V.I. 2 , Ph.D. (Engineering), Associate Professor, e-mail: vikuzmin57@mail.ru 1 Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russian Federation 2 Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, 4/1 Institutskaya str., Novosibirsk, 630090, Russian Federation Abstract Boron carbide coatings were obtained by air-plasma spraying with annular injection of powder. Two different configurations of plasma torch were used for the application of the coatings. Commercially manufactured 70 wt% B 4 C/30 wt% Ni (B 4 C-30Ni) clad powder and «pure» boron carbide powders of 20 (B 4 C-20) and 40 (B 4 C-40) μm were used. B 4 C-30Ni coatings were applied using «Metal» configuration of plasma torch, which provides lower plasma temperatures and is used for application of metals. Coatings from «pure» B 4 C powder were sprayed using «Ceramics» configuration, which provides higher temperatures and lower plasma flow rates. Optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy revealed that B 4 C-30Ni coatings exhibit low porosity and consist of boron carbide particles surrounded by matrix of nickel borides. SEM of B 4 C-20 revealed cracks inside the coating whereas B 4 C-40 appeared solid. It was found that the B 4 C-40 exhibit the highest Vickers hardness that is in the range of 40 to 45 GPa. Thus the possibility of formation of high quality ultra hard coatings out of boron carbide was shown. These findings have significant importance to the development of boron carbide coatings for high-performance applications. Keywords plasma spraying, annular injection, coating, boron carbide, B 4 C, B 4 C-Ni-P