OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 1 2023 the first one was constantly the C65500 itself while the second was made of an alloy to be intermixed with bronze. Commercially pure aluminum (99% Al) and AK5 (Al-5Si) and AK12 (Al-12Si) alloys were used as such additives. The both wires’ feed rates were adjusted in such a way as to ensure the addition of 10 wt.% of aluminum to the C65500 alloy. As a result, three alloys were obtained: 1) C65500 + 10 wt.% Al, 2) C65500 + 10 wt.% Al-5Si and 3) C65500 + 10 wt.% Al-12Si. The technique for printing specimens is described in more detail elsewhere [23]. Corrosion resistance of bronze specimens was studied by conducting potentiodynamic tests on a threeelectrode circuit and using a potentiostat Electrochemical Instrument P-45X. An aqueous solution of 3.5% NaCl was used as a corrosive medium. As a result, polarization curves were obtained that reflected the changes in potential and corrosion current. The polarization resistance is calculated basing on the ButlerVolmer equation: Rp = (βaβc)/(2.303Icorr(βa + βc)), (1) where βa is the slope of the anode branch, β c is the slope of the cathode branch, icorr is the corrosion current. The weight loss of the specimens was assessed using a Sartorius CP 124 S analytical balance. The surface of bronze specimens after the corrosion resistance test was examined using a confocal laser scanning microscope Olympus OLS-4100. To perform both qualitative and quantitative assessments of the corrosion damage to the surface, optical images were obtained and the roughness was evaluated. Sliding tests were carried out using a Tribotechnic tribometer according to the ball-on-disk scheme under conditions of reciprocating dry sliding friction. Plates cut from printed bronze walls were used as specimens (see Figure 1. pos. 8). Balls made of hardened steel AISI 52100 were used as counterbodies. The study of the surface of bronze specimens and balls after friction, as well as the measurement of the crosssectional profile of the wear tracks, was carried out using a confocal laser scanning microscope Olympus OLS-4100. Microhardness was measured using a Duramin-5 hardness tester at a load of 50 N. The tensile strength characteristics were evaluated on a Testsystem 110 M-10 testing machine. The study of the phase composition of bronze specimens was carried out on a DRON-7 X-ray diffractometer. The elemental composition was determined using Octane Elect energy dispersive spectral (EDS) analysis on a Thermo Fisher Scientific Apreo S LoVac scanning electron microscope. Metallographic studies of the structure of bronze specimens were performed using a confocal laser scanning microscope Olympus OLS -4100. Fig. 1. Scheme of electron beam additive manufacturing and cut-up sketch: 1 – printed material; 2 – substrate; 3 – wire feed direction; 4 – wire feeder; 5 – printing direction; 6 – electron beam; 7 – tensile test specimens; 8 – friction and corrosion resistance test specimen
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