OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 3 2024 The main disadvantage of titanium alloys is low wear resistance, which leads to the release of wear products into the patient body. Another disadvantage of titanium is the lack of antibacterial properties, which can lead to infection or inflammation during clinical use and even to unsuccessful implantation [4, 5]. Antibacterial coating can reduce infections and inflammations caused by surgical contamination [6]. Copper-titanium coatings are known to effectively improve the antibacterial properties of titanium alloy and at the same time increase its wear resistance [7, 8]. Cu-Ti coatings are applied by magnetron sputtering [9–12], plasma spraying [6] and electrospark deposition (ESD) [13]. ESD is a high-energy process, the main advantages of which are the metallurgical bond of the formed coating to the substrate, the ability to select the coating thickness (from several units to several tens of micrometers), low thermal effect on the base material and simple equipment that does not require vacuum [14]. ESD technology is based on many low-voltage electrical discharges passing between the electrode and the workpiece in a gas environment. During the discharge, a microbath of molten metal on the cathode surface is formed, into which the material is transferred from the anode, the so-called polar transfer. As a result of convective and diffusion mixing of the anode and cathode materials, high adhesion of the coating to the substrate is provided. Due to the short discharge lifetime ≤ 10−4 s the low thermal effect on the substrate is ensured [15, 16]. In this work, a non-localized electrode was used, which ensured automation of ESD processing. The concept of a non-localized electrode is based on the use of a set of millimetersized granules as a source of deposited material [17–19]. Previously, we deposited Cu-Ti coatings by the method of electrospark deposition (EGD) using a non-localized electrode [20, 21] and studied its wear behavior under dry sliding conditions. However, there is no information in the literature on the corrosion and tribological behavior of copper-titanium coatings in physiological solutions, despite the fact that a significant effect of electrolytes on the friction coefficient, wear mechanism of materials and corrosion properties is known. The purpose of the work is to study the effects of a solution simulating body fluid (SBF) on corrosion properties, friction coefficient and the wear rate of copper-titanium coatings obtained by electrospark deposition method of the Ti-6Al-4V alloy. Research methodology Copper-titanium coatings were prepared by the EGD method using a non-localized electrode (NE) as an anode. It consisted of a set of cylindrical granules (d = 4 ± 0.5 mm, h = 4 ± 1 mm) of titanium VT1-00 and copper M0. The composition of five NEs with different ratios of titanium and copper granules is presented in Table 1. Cylinders (h = 10 mm, d = 12 mm) made of industrial titanium alloy Ti-6Al-4V were used as a substrate (cathode). Before applying the coatings, the substrates were processed on P600 abrasive paper, then alternately washed in water and alcohol using an ultrasonic bath and dried in a drying oven at 90 °C. The sets of granules were poured into a titanium container, in the center of which the substrate was placed. The substrate and container were connected to the negative and positive leads of the pulse generator, respectively. The substrate and container with granules were rotated in opposite directions with a frequency of 60 rpm using motors. The pulse generator operating parameters were as follows: pulse duration 100 μs, repetition frequency 1 kHz, voltage 30 V, current pulse amplitude 110 A. Surface oxidation and nitriding during coating application were eliminated by feeding argon into space of the container with granules. Each set of granules was run in on a non-replaceable cathode for ~2 hours. The processing of one sample lasted 10 minutes. The method of deposition of Cu-Ti coatings is described in detail in [19–21]. Ta b l e 1 Composition of a set of granules for coating Sample designation Cu10 Cu30 Cu50 Cu70 Cu90 Cu, at. % 10 30 50 70 90 Ti, at. % 90 70 50 30 10
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