PSI - Issue 59

Igor Stadnyk et al. / Procedia Structural Integrity 59 (2024) 672–678 Igor Stadnyk et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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Institute of Vegetable and Melon Growing of the National Academy of Sciences of Ukraine in September-October 2020-2021. According to the institute data, the most popular varieties in Ukraine are Snow White, Ukrainian Autumn and Yaroslavna. These cabbage varieties are included in the State Register of Plant varieties suitable for distribution in Ukraine (State register, 2019). Regarding the content of sulfur-containing compounds in the leaves, its advantage was observed in Yaroslavna variety (908.08 mg/kg), slightly smaller proportion was determined in Ukrainian Autumn variety (570.42 mg/kg), and the smallest one - in Snow White variety (76.85 mg/kg). Accordingly, the Yaroslavna variety (908.08 mg/kg) was taken as sample No. 1, and the Ukrainian Autumn variety (570.42 mg/kg) was chosen as sample No 2. Hypochlorous acid is used as a disinfectant to treat the equipment operating surfaces, and water is used for cooling systems. Therefore, tap water (pH 7.2; mineralization 372.4 mg/l; total hardness 4.7 mol/l; total iron 0.4 mg/l) and 0.1 M HCl solution were investigated as operating medium (Khoma et al., 2022). The investigation was carried out on steel 20, the most common structural material. Method of investigating the corrosion process. The level of corrosion was determined by the mass spectrometry method. The tests were carried out on the samples in the form of rectangular plates. The samples were polished with fine abrasive material mechanically, marked and degreased with ethyl alcohol. The resulting samples were weighed by analytical balance with ±0.0001 g accuracy. After the tests, the plate samples were cleaned of corrosion deposits, washed, dried and re-weighed. The corrosion rate is determined by the formula:

, (m 2 /h)

(1)

where Mn is the initial mass of the sample, g; Mk is the sample mass after the investigation, g; S is the sample area, m 2 ; τ is the duration of the investigation, h. The corrosion rate reduction factor (J) is calculated by the following formula

,................................................................................................................................................................ (2)

where W i is the inhibitor corrosion rate, W x is the blank sample corrosion rate. The degree of corrosion protection (Z) is calculated on the basis of corrosion rate reduction factor using the following formula:

1

  

1     

;

(3)

100%

Z

j

Sulfur-containing and volatile compounds were investigated by GC/MS method ((Dovhal et al., 2016; Kityk et al., 2021). For in-depth investigation of the mechanism of inhibitors action on the sample surface, optical (Neofot-21) and electron (REP-200) microscopy, electrochemical potentiostatic measurements (P-5827M), X-ray structural analysis (DRON-2.0), derivatography and thermography (PAVLYK- ERDEN, TG-750) were used. The inhibition efficiency in the operating environment of the experimental installation was evaluated using UISK-2 corrosion meter ((Khaburskyi et al. (2015). Mathematical processing of the investigation results and probability of the obtained results was 0.9835, and measurement error did not exceed 5%. The developed in TurboPascal language modeling system version 7.0 was used, which made it possible to search the optimal model automatically. The results of the experiment are shown in Table 1 and Fig. 2. Evaluating anti-corrosion activity in drinking water revealed changes in the metal surface, which were visually noticed on the second day. Corrosion products in the form of brown precipitate fell to the bottom of the glass. In the environments with investigated inhibitors, the plate surface remained clean during 167 hours of the investigation, and the corrosion rate decreased by 7 – 10 times. The nature of the corrosion rate change and the protective coating efficiency depending on the reagents consumption is described by the third-order equations: , R 2 =0.9835