PSI - Issue 40

A.A. Ushkanov et al. / Procedia Structural Integrity 40 (2022) 440–444 A.A. Ushkanov, S.A. Sleptsova / Structural Integrity Procedia 00 (2022) 000 – 000

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The International Group of Climate Experts released the sixth report in 2021 (Masson-Delmotte et al. (2021)). It is noted that since the beginning of the 20th century, the temperature on the planet has already increased by a critical 1.1 degrees Celcius. The report also says that another three degrees of warming are more likely to lead to the complete disappearance of Arctic ice. As you know, melting ice can cause a risk of rising sea levels, as well as the possible spread of microorganisms unknown to science. From the point of view of environmental impact, the emission of harmful substances from blast furnaces in obtaining basalt fibers is practically zero, which in turn shows their environmental safety compared to glass and carbon fibers (Yan et al. (2020)). The modern world is characterized by increased attention to the development of server regions due to raw materials, transport, military, and geopolitical reasons. The northern areas mean parts of a cold climate, regardless of their geographical location, since hard is the main climatic characteristic not only, for example, of the Arctic, but also of other regions of Eurasia, such as the Republic of Sakha (Yakutia), where temperature conditions are often more severe than in the ice and sea parts of the continent. The development of the Arctic requires the creation of polymer composite materials that ensure the reliable operation of technology. For example, polymer composite materials in tribology often require high wear resistance and a low coefficient of friction (Buznik and Kablov (2018)). The protection of ecology and the environment is the essential condition for developing the Arctic and its existence. 2. EXPERIMENT 2.1. Materials and Methods For the manufacture of composite materials, we used PTFE grade PN-90, manufactured by HaloPolymer JSC TU 2213-022-13693708-2005, GOST 10007-80. Basalt fibers were used as reinforcement for PTFE-based composites, as well as carbon fibers for comparison. Basalt fibers produced by LLC TBM, Pokrovsk, Republic of Sakha (Yakutia) are crushed in a Fritsch Pulverizette 15 mill with an installed sieve measuring 0.25 mm. The length of the fibers varies in the range of 30-90 µm, and their diameter is 8.0 - 10.0 µm. Basalt fiber - has several characteristics, such as breaking strength, elastic modulus, operating temperature range, in which it surpasses other types of fibers, including its closest analog - glass fiber (Rybin (2016)). Carbon fibers of the "Belum" brand produced by JSC SvetlogorskKhimvolokono were modified by plasma chemical treatment in an environment of organofluorine compounds. The fiber's width and length are 8 –10 µm and 50 –500 µm, respectively (Vasilev et al. (2016)). Samples for testing were prepared by dry mixing of pre-dried components followed by molding, after which they were sintered in a muffle furnace at a temperature of 375°C and calibrated. The main technical characteristics were obtained using standard methods. The mass wear rate (GOST 11629-2017) was investigated on a CETR UMT-3 friction machine (USA) according to the "finger-disc" friction scheme (sample-column with a radius of 5 mm from the center, counter body is a steel shaft made of 45 sheets of steel with a hardness of 45 50 HRC) at a specific pressure of 2 MPa, sliding speed 0.2 m/s. To assess the degree of crystallinity of the composite, which affects the strength of the material and its physical and mechanical properties, we used the DSC 204 F1 Phoenix Netzsch differential scanning calorimeter (DSC) method (Germany) and the ARL X'TRA X-ray diffraction analysis (XRD) method from Thermo Fisher Scientific (Switzerland). The supramolecular structure and friction surfaces of the composites were studied using a scanning electron microscope (SEM) JSM-7800F LV (JEOL, Japan). 3. RESULTS As you can see from the table 1, with the introduction of reinforcing fillers into composites based on PTFE, the friction coefficient increases (by 1.8 times), but at the same time, the wear rate is significantly reduced (up to 400 500 times). It was found by Kurguzova (2014) that this is due to the formation of spherulites of various shapes and