Preparation of Polymer Coatings for Protection of Metal Structures from Corrosive Effects

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1. Introduction Concrete and reinforced concrete are the most common building materials, and therefore the problem of increasing the durability of various buildings and structures is particularly relevant. Corrosion protection is one of the most important scientific, environmental, social and economic challenges, since technical progress in many industries is hampered by a number of unresolved problems of corrosion control. The significance of corrosion processes is particularly evident in enterprises that use metal structures, equipment, machinery, tools and transportation with substantial wear and tear during their service life. According to open sources, annual direct global losses from corrosion are estimated at 1.8 trillion dollars.[1] The importance of corrosion studies is determined by three aspects: Ø economic - aims to reduce material losses as a result of corrosion of metallic and non-metallic structures and products; Ø improving the equipment reliability, which as a result of corrosion can be destroyed with catastrophic consequences; Ø metal stock preservation. The world’s metal resources are limited, and metal losses due to corrosion lead to additional energy and water costs. Equally important, the human labor spent on the design and reconstruction of metal structures and equipment affected by corrosion can be directed to other socially useful tasks [1; 2]. This is most relevant in countries with a large metal stock due to the increasing use in the industry (construction, metallurgical, machine-building, etc.) not only of high-strength materials, but also of particularly aggressive media, high temperatures and pressures. Under these conditions, the specific weight of metal losses increased significantly. Polymer coatings are widely used to protect metals from corrosion. They not only protect the metal from corrosive and other chemical influences, but also give the building structure or metal product excellent electrical insulation, decorative, antiseptic and other properties. Compared to paint and enamel, polymer coatings have a number of advantages. They are more durable, more elastic, better bonded to the metal; in the process of operation, they rub off and crack much less than enamels. The requirements for polymer coatings are quite serious. First, they must exhibit very high surface adhesion as they bond to the metal base at the molecular level rather than just coating it. Polymer coatings not only protect metals from the effects of aggressive environments, but also increase their wear resistance, reducing the adhesion of various substances to the working surfaces, allow saving non-ferrous metals and other scarce materials [3; 4]. Scientists of many countries are engaged in the problem of corrosion of metal building structures or products, developing polymer coatings with the required complex of properties. Thus, in paper [5] the authors cite the technology of obtaining a composition for protective and decorative coating on a building material, including film-forming component (polyester resin 5.0-20.0% wt.), binding component (polyvinyl acetate emulsion 30.0-60.0% wt.), pigment 5.0-30.0% wt., plasticizer (diethylene glycol 2.0-15.0% wt. and butadiene-styrene copolymer in the form of “Bustilat” glue 5.0-10.0% wt.), polymerization initiator (ammonium persulfate 5.0-15.0% wt.) and water (rest). However, this protective coating is a complex composition including expensive functional additives. The technology of obtaining the composition for the protection of steel structures and equipment made of carbon steel was developed by the authors of [6]: the obtained anticorrosive polymer coating consists of (part weight h): epoxy-diane resin (100), dibutyl phthalate, (10-20), highly dispersed silicon dioxide (1.5-3) with a specific surface area of 150-400 m2/g, acid hardener (30-50), mineral filler (100-550), accelerant, for example, dimethylaniline (0.1-0.5). Phthalic and maleic anhydrides can be used as acid hardener. The composition ensures increased corrosion and wear resistance. The developed protective polymer coating is difficult to prepare, is multi-component and belongs to hot curing coatings, which limits its application. In papers [7; 8], a composition for anticorrosion coating used in various industrial fields is proposed, including film-forming agent - copolymer of trifluorochloroethylene with vinylidene fluoride F-32L, organic solvent - acetone, butyl acetate, additionally contains pigments - aluminum powder, or titanium dioxide, and/or blue phthalocyanine pigment, and/or yellow iron oxide pigment, and/or red iron oxide pigment, and/or technical carbon, and as an organic solvent additionally contains toluene and ethyl acetate. Combination of components in a certain ratio results in coatings with adhesion to steel of 75-810 N/m, impact strength of 12-15 J and drying time of 2.0-2.5 h, while maintaining the values of flexural strength and resistance to vapors of 30% HCl at 90 °С. However, the coating developed by this technology has low adhesion and negligible water resistance. The authors of papers [9; 10] offer a technology for obtaining protective polymer coatings characterized by a composition based on copolymers, solvent, modifier, filler and hardener containing copolymers of vinyl-n-butyl ether (VBE), methyl methacrylate (MMA), maleic anhydride (MA) and low molecular weight dimethyldihexylbutyndiol as a modifier at the following ratio of components, % pts. wt.: copolymer VBE:MMA:MA 30-70, solvent 10-50, modifier 0.5-1.5, filler 20-60, and having corrosion properties of corrosion-resistant coatings. A lot of scientific studies are aimed at obtaining composite protective polymer coating using silicon production wastes - microsilica (microsilicas, nanosilicas), as well as with zinc production wastes - zinc ashes [11-19]. The filler for polymer coatings is selected depending on the application. For example, for polymer coating of concrete floors, the composition may include silica sand, corundum and other substances that increase strength and resistance to abrasion. For metal surfaces it is steel, aluminum and other powder, as well as fibers. Products with such fillers are close in strength to the base material. The compositions may also include coloring agents [20]. Therefore, effective measures that can lead to the development of polymer protective coatings of new formulations are needed. The authors of this article, having made a literature and patent analysis, offer a technology for creating a corrosion-resistant polymer coating, using various fillers (Figure 1). a b Figure 1. Filler appearance: a - microsilica; b - titanium oxides S o u r c e: made by I. Volokitina The purpose of this study is to develop a technology for obtaining a composition of protective coating based on copolymers with corrosion properties, as well as the possibility of using this coating to protect against the effects of aggressive environments of metal products. The object of research is the obtained protective polymer coating with the use of various fillers. The following tasks are set for fulfillment of the specified purpose: 1) development of the technology of copolymer production; 2) selection of formulation for a new polymer coating for protection of metal structures and products from the effect of aggressive media; 3) selection of fillers for making the polymer coating; 4) development of complex technology of obtaining protective polymer coating on the basis of copolymers; 5) determination of physical and mechanical properties of the obtained corrosion-resistant polymer coating. In the course of the study, a copolymer based on vinyl butyl ether, styrene and methyl methacrylate was obtained. On the basis of the obtained copolymer, the composition of the protective coating was developed. 2. Methods Methyl methacrylate and vinyl butyl ether were poured into a three-neck flask and maleic anhydride (copolymer 1) was loaded into the flask. 100 g of toluene was loaded after the maleic anhydride was dissolved. The heating temperature of the monomer mixture is about 60 °C. Then 0.2 g of dinitrilazoiso- butyric acid polymerization initiator was added. Copolymerization occurs when slowly heated to a tem- perature of 70-80 °C for 1-2 hours. The reaction mixture was incubated for 24 hours (1 day) to mature the copolymer. The synthesis of copolymer 2 (methyl methacrylate and vinyl butyl ether) with different ratios of initial components was carried out in a similar manner. The obtained copolymers were blended with fillers in order to change their technological and operational properties in a directed manner. After preparation of copolymers (Figure 2-4) of different compositions, they were mixed with fillers - microsilica, titanium oxide and jointly titanium oxide and microsilica at the same copolymer to filler ratio of 3:1. During the mixing of the components, a solvation process occurred with vigorous bubbling lasting 15 min followed by a settling process. The drying time is 24 h after applying polymer coatings to the samples. Figure 2. Copolymer preparation Figure 3. Finished copolymer materials for coating application S o u r c e: photo by I. Volokitina S o u r c e: photo by I. Volokitina Figure 4. Finished polymer coatings for metal samples S o u r c e: photo by I. Volokitina Table 1 shows the formulation of the developed protective polymer coatings. The method used was dip coating, a process in which a substrate is immersed in a liquid and then extracted under controlled environmental conditions, ultimately resulting in a coating. Determination of hardness, adhesion, thickness of coatings was carried out according to state-approved methods. The microstructure was studied by electron microscopy on a Jeol microscope. Table 1 Compositions of developed polymer coatings No. of coverage Composition Polymers Filling materials Copolymer 1 ММА:VBE:МА Copolymer 2 ММА:VBE SiO2 TiO2 1 - + - + 2 - + + - 3 - + + + 4 + - - + 5 + - + - 6 + - + + N o t e : MMA - methyl methacrylate; VBE - vinyl butyl ether; MA - maleic anhydride; SiO2 - microsilica powder; TiO2 - titanium dioxide powder. S o u r c e: made by I. Volokitina 3. Results and Discussion The obtained polymer coatings were applied to metal plates (Figures 5-7). Figure 5. Polymer coating with titanium oxide filler Figure 6. Polymer coating with microsilica filler S o u r c e: photo by A. Yepaneshnikova S o u r c e: photo by A. Yepaneshnikova Figure 7. Combined polymer coating S o u r c e: photo by A. Yepaneshnikova Plates with the studied coating and uncoated plates were placed in different aggressive media in order to determine the behavior of the obtained polymer coatings and to calculate their corrosion resistance. The composition of aggressive media is as follows: H2SO4 acid - 5% and 10%; KOH base - 5% and 10%; NaCl salt - 10%. The plates were incubated in aggressive media for 24 hours (Figure 8). a b c Figure 8. Immersion of metal samples in aggressive media: a - samples with titanium filler; b - samples with microsilica filler; c - samples with combined polymer coating S o u r c e: photo by A. Yepaneshnikova Table 2 describes the behavior of polymer coatings in contact with aggressive media. According to the results of Table 2, it can be seen that the samples with titanium dioxide filler withstood the test in hydrochloric medium and in 10% KOH medium. Microsilica filled coating showed the best results after exposure to aggressive environments (5% H2SO4). Samples with combined polymer coating showed very good results when exposed to aggressive media: salt solution and sulfuric acid solutions. The appearance of samples after exposure to aggressive media is shown in Figure 9. The rate of corrosion of metals at their uniform destruction is determined by the depth index Kg (mm/year): Kg = K ⋅1000 , (1) ρ Km- - corrosion rate, g/(m2·h); 8760 - number of hours per year; ρ - density of metal, kg/cm3. where Mass loss per unit surface area Δm, kg/m2, is calculated by the formula: Δm= mo -m1 , (2) S where mo - mass of the specimen before testing, kg; m1 - mass of the sample after testing and removal of corrosion products, kg; S - surface area of the sample, m2. a b c d e f Figure 9. Appearance of samples after exposure to aggressive media: a - coating with titanium filler (series 1); b - coating with titanium filler (series 2); c - coating with microsilica filler (series 1); d - coating with microsilica filler (series 2); e - combined polymer coating (series 1, series 2, series 3); f - metal samples without coating S o u r c e: photo by A. Yepaneshnikova Table 3 shows the weight of coated samples before and after exposure to aggressive media and corrosion score according to Interstate standard GOST 9.908-852.1 Table 3 Results of determination of corrosion weight score of polymer coatings with fillers (microsilica and titanium oxide) 5% NaCl mo, g 12.43 11.92 11.78 12.19 mк, g 12.45 11.88 11.81 12.16 V, g/m2*h 0.00083 0.00167 0.00125 0.00125 С 0.001 0.0019 0.0014 0.0014 R, % quite resistant / 2 quite resistant / 2 quite resistant / 2 quite resistant / 2 Δm, % 0.16 0.34 0.25 0.25 5% H2SO4 mo, g 11.94 11.60 11.11 11.56 mк, g 11.56 11.24 11.14 11.60 V, g/m[2]*h 0.0158 0.0150 0.00125 0.00167 С 0.0178 0.0169 0.0014 0.0019 R, % resistant / 4 resistant / 4 quite resistant / 2 quite resistant / 2 Δm, % 3.18 3.10 0.27 0.35 Ending of the Table 3 10% H2SO4 mo, g 11.90 11.86 13.02 15.76 mк, g 11.72 11.68 13.06 15.73 V, g/m2*h 0.0750 0.0750 0.00167 0.00125 С 0.0084 0.0084 0.0019 0.0014 R, % quite resistant / 3 quite resistant / 3 quite resistant / 2 quite resistant / 2 Δm, % 1.51 1.52 0.31 0.19 5% КOH mo, g 11.33 11.45 11.89 12.14 mк, g 11.42 11.49 12.30 11.10 V, g/m2*h 0.0038 0.00167 0.01708 0.04333 С 0.0042 0.0019 0.0192 0.0487 R, % quite resistant / 2 quite resistant / 2 resistant / 4 resistant / 4 Δm, % 0.79 0.35 3.45 8.57 10% КOH mo, g 12.50 12.15 12.08 16.37 mк, g 12.17 12.63 12.67 15.39 V, g/m2*h 0.0138 0.0200 0.0246 0.0408 С 0.0154 0.0225 0.0276 0.0459 R, % resistant / 4 resistant / 4 resistant / 4 resistant / 4 Δm, % 2.64 3.95 4.88 6.00 S o u r c e: made by I. Volokitina The results of Table 3 show that the introduction of maleic anhydride into the composition of polymer coating significantly increases corrosion processes, i.e. decreases their corrosion resistance. Effect of aggressive media: the series samples with TiO2 filler withstood the effect of aggressive media better in hydrochloric and alkaline solutions, and the series samples with SiO2 filler can perform well, on the contrary, in acidic media. Table 4 shows the weight of samples with combined polymer coating before and after exposure to aggressive media and the corrosion score. The results of Table 4 show that the combined polymer coating of series 2 performed well in hydro- chloric and acidic solutions, worse in alkaline solutions. This is probably due to the presence of styrene in the composition of the combined coating, which has good resistance to aggressive media. Series 1 combined polymer coating has good resistance to salt solution and 5% H2SO4 solution. Series 3 combined polymer coating has average values of corrosion resistance in all presented aggressive media (score not higher than 4). The combined polymer coating with microsilica filler performed the worst in aggressive media; it has the highest corrosion rate, weight loss and corrosion scores. Figure 10 shows a comparative plot of the change in corrosion rate of polymer coatings after exposure to aggressive media. Figure 11 shows a comparative analysis of the weight change of the polymer coatings after exposure to aggressive media, and Figure 12 shows the score of the polymer coatings. Figures 10-12 show that the combined polymer coating with microsilica filler performed the worst in aggressive media; it has the highest corrosion rate, mass loss and corrosion score. Table 4 Results of determining the corrosion weight score of the combined polymer coating mo, g 12.87 12.53 16.78 mк, g 12.85 12.47 16.66 V, g/m2*h 0.0008 0.0250 0.0050 С 0.001 0.0028 0.0056 R, % quite resistant / 2 quite resistant / 2 quite resistant /3 Δm, % 0.16 0.48 0.71 5% H2SO4 mo, g 12.68 12.98 12.52 mк, g 12.63 12.95 12.43 V, g/m2*h 0.0021 0.0013 0.0038 С 0.0023 0.0014 0.0042 R, % quite resistant / 2 quite resistant / 2 quite resistant / 2 Δm, % 0.39 0.23 0.72 10% H2SO4 mo, g 17.11 17.26 16.95 mк, g 16.86 17.21 17.09 V, g/m2*h 0.0104 0.0021 0.0058 С 0.0117 0.0023 0.0066 R, % resistant / 4 quite resistant / 2 quite resistant / 3 Δm, % 1.46 0.29 0.83 5% КOH mo, g 11.65 12.42 12.55 mк, g 12.87 12.73 12.86 V, g/m2*h 0.0508 0.0129 0.0129 С 0.0571 0.0145 0.0145 R, % resistant / 5 resistant / 4 resistant / 4 Δm, % 10.47 2.50 2.47 10% КОН mo, g 16.53 13.61 12.34 mк, g 12.59 13.20 12.59 V, g/m2*h 0.1642 0.0171 0.0104 С 0.1844 0.0192 0.0117 R, % low-resistant / 6 resistant / 4 resistant / 4 Δm, % 23.84 3.01 0.36 S o u r c e: made by A. Yepaneshnikova Figure 10. Graph of change in corrosion rate of polymer coatings after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 11. Graph of change in weight of polymer coatings after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 12. Score of polymer coatings S o u r c e: made by G. Ulyeva The photo shows microstructures of polymer coatings (Figure 13-19) obtained from the scanning electron microscope “Zeiss” in laboratory of metal science and defectoscopy of the Analytical Control Center of “Qarmet” JSC. Figure 13. 1SiO2 polymer coating after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 14. 3SiO2 polymer coating after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 15. 1ТiO2 polymer coating after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 16. 3ТiO2 polymer coating after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 13 shows that the 1SiO2 polymer coating has a uniform homogeneous structure after exposure to the aggressive media. The 3SiO2 polymer coating after exposure to aggressive media is also uniform and homogeneous, but local microcracks are observed at high magnification (Figure 14). 1TiO2 polymer coating has a similar structure after exposure to aggressive media (Figure 15). In polymer coating 3TiO2 after exposure to aggressive media microcracks are observed in some places already at low magnification, the coating itself has a uniform homogeneous structure (Figure 16). Combined polymer coating of series 1 after exposure to aggressive media has a uniform homogeneous structure, microcracks are also observed in some areas at low magnifications (Figure 17). Figure 17. Combined polymer coating of series 1 after exposure to aggressive media S o u r c e: made by G. Ulyeva Combined polymer coating of series 2 after exposure to aggressive media is characterized by a some- what heterogeneous structure, there is a local swelling of the coating, but there are no microcracks (Figure 18). Combined polymer coating of series 3 after exposure to aggressive media is characterized by a uniform, homogeneous structure, there is an interesting pattern of “crystallization”, and there are no microcracks (Figure 19). Further, the adhesion of the polymer coating to the metal base was analyzed by scratch grid method according to Interstate standard GOST 15140-78[3].2The scratch grid method consists in that four-six parallel lines with depth to the base metal at a distance of 2-3 mm from each other and four-six parallel lines perpendicular to the first ones are drawn on the surface of the controlled coating with a steel point. No peeling should be observed on the controlled surface of the coating[4].3 Figure 20 shows the applied scratch grid on the polymer coating. Table 5 shows the test results of polymer coatings with different filler for adhesion properties. Figure 18. Combined polymer coating of series 2 after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 19. Combined polymer coating of series 3 after exposure to aggressive media S o u r c e: made by G. Ulyeva Figure 20. Example of scratch grid application S o u r c e: made by V. Merkulov Determination of adhesion of polymer coatings on metal samples Table 5 NaCl H2SO4 5% H2SO4 10% KOH 5% KOH 10% 1 2 3 4 5 MMA+VBE+MA+TiO2 (1TiO2) The coating No delamination The coating crumbled The coating crumbled The coating crumbled crumbled when of the coating during when the scratch when the scratch grid when the scratch grid the scratch grid scratch application grid was applied was applied was applied was applied VBE+MMA+TiO2(3TiO2) The coating generally When applying the scratch The coating adheres The coating has The coating has has good adhesion grid, the coating peeled off tightly to the base; there completely peeled off completely peeled but crumbles locally (in one place), is no peeling in all the when the scratch grid off when the scratch at the intersections but overall withstood the test scratch grid crosshairs was applied grid was applied of the scratch grid MMA+VBE+MA+SiO2 (1SiO2) The coating has The coating has The coating has The coating did not peel The coating did not peel completely peeled completely peeled off completely peeled off when the scratch off when the scratch off when the scratch grid when the scratch grid off when the scratch grid was applied grid was applied was applied was applied grid was applied VBE+MMA+SiO2 (3SiO2) When applying the scratch When applying the When applying the scratch The coating has The coating has grid, the coating did scratch grid, the coating grid, the coating did not completely peeled off completely peeled not peel off, tightly did not peel off, tightly peel off, tightly adheres when the scratch grid off when the scratch adheres to the base adheres to the base to the base was applied grid was applied MMA+VBE+MA+TiO2+SiO2 (1 series combined) When the scratch grid was When applying the scratch When applying the The coating has The coating has applied, the coating did not grid, the coating scratch grid, the coating completely peeled completely peeled peel off, leaving scratches did not peel off, tightly did not peel off, tightly off after exposure off after exposure in the coating but still adheres to the base adheres to the base to aggressive media to aggressive media adhering tightly to the base MMA+VBE+styrene+TiO2+SiO2 (2 series combined) When applying the When applying the When applying the scratch When applying the When applying the scratch scratch grid, the scratch grid, the grid, the coating scratch grid, the coating grid, the coating coating did not peel coating did not peel did not peel off, tightly did not peel off, tightly did not peel off, tightly off, tightly adheres off, tightly adheres adheres to the base adheres to the base adheres to the base to the base to the base VBE+MMA+SiO2+ТiO2 (3 series combined) When applying the When applying When applying the scratch When applying the When applying the scratch scratch grid, the the scratch grid, grid, the coating did not scratch grid, the coating grid, the coating coating did not peel the coating did not peel off, tightly adheres did not peel off, tightly did not peel off, tightly off, tightly adheres peel off, tightly to the base adheres to the base adheres to the base to the base adheres to the base S o u r c e: made by V. Merkulov According to the results of Table 5, it can be seen that samples No. 1 of 1TiO2 and 3TiO2 series have good adhesion properties with the base. Samples Nos. 1-2 of 1SiO2 series and samples Nos. 1-3 of 3SiO2 series have the best adhesion properties with the base. Series 2 and 3 combined polymer coatings have the best adhesion properties. Series 1 combined polymer coating has good adhesion properties except for the samples exposed to aggressive media (5 and 10% KOH). The authors decided to determine the hardness of the coatings in order to evaluate the effect of coating composition and aggressive media on this mechanical characteristic. Hardness was determined using a MET-UD portable combination hardness tester. Hardness was determined on a selected Brinell scale. This hardness tester determines hardness electronically by measuring the change in ultrasonic frequency and by determining the ratio of the velocity of the striker inside the transducer before and after impact. The striker, located in the dynamic sensor, has a carbide ball at the end, which is directly connected to the controlled surface at the moment of impact. There is a permanent magnet inside the striker. After the trigger is pressed, the striker is ejected onto the surface to be measured by means of a preloaded spring. In this case, the striker moves inside the inductance coil and induces EMF in it by its magnetic field. The signal from the output of inductance coil is fed to the input of the electronic unit, where it is converted to the value of hardness of the selected scale and displayed on the screen. Table 6 shows the average Brinell hardness results of the samples after exposure to aggressive media. Table 6 Results of hardness measurements of polymer coating samples on metal Solution Hardness, НВ Coating 1ТiO2 Coating 3ТiO2 Coating 1SiO2 Coating 3SiO2 Cncoated sample 5% NaCl 244.6 219.4 210.6 214.8 204.4 5% H2SO4 233.2 233.8 182.4 195.4 211.6 10% H2SO4 272.2 239.0 247.0 175.4 200.4 5% КOH 310.6 227.0 232.0 264.4 192.0 10% КOH 221.5 228.6 192.6 230.4 203.4 Medium 254.4 229.6 212.9 216.1 202.4 S o u r c e: made by G. Ulyeva According to Table 6, the highest hardness values are found in titanium filled coatings of both series. Accordingly, the uncoated sample has the lowest values, indicating exposure to aggressive media and metal corrosion. It can be concluded that both titanium-filled and microsilica-filled coatings have protective properties against corrosion, since the hardness of the polymer-coated samples is greater than that of the uncoated sample. Table 7 shows the average hardness results of the combined polymer coating samples after exposure to aggressive media according to the Brinell method. Table 7 Results of hardness measurements of combined polymer coating samples on metal Solution Hardness, НВ Series 1 coating Series 2 coating Series 3 coating 5% NaCl 133.7 253.7 187.7 5% H2SO4 156.7 182.8 239.7 10% H2SO4 150.0 143.0 168.8 5% КOH 233.3 206.0 248.0 10% КOH 204.0 233.0 231.3 Medium 175.5 203.7 215.1 Not covered 213.0 214.5 203.5 S o u r c e: made by G. Ulyeva According to Table 7, the hardness of metal samples with combined polymer coating is less than that of polymer coated samples with different fillers individually. However, the combined polymer coating of series 3 has the highest hardness value compared to series 1 and 2. The thickness of coatings was also determined in accordance with National standard of the Russian Federation GOST R52146-2003[5]4“Polymer-coated rolled products”. Table 8 shows the results of determining the thickness of the polymer coating using an electronic micrometer MK-25 (mechanical testing laboratory of the Analytical Control Center of “Qarmet” JSC) after exposure to aggressive media. Table 8 Results of thickness measurements of polymer coatings with titanium oxide and microsilica fillers, µm Solution Coating 1ТiO2 Coating 3ТiO2 Coating 1SiO2 Coating 3SiO2 5% NaCl 0.096 0.152 0.217 0.687 5% H2SO4 0.093 0.093 0.267 0.197 10% H2SO4 0.059 0.103 0.338 0.256 5% КOH 0.875 0.113 0.159 0.179 10% КOH 0.119 0.091 0.220 0.277 Medium 0.249 0.111 0.241 0.320 S o u r c e: made by G. Ulyeva According to the results of Table 8, it can be seen that the highest thickness values have the polymer coating with microsilica filler of series 3, but at the same time this coating has low hardness values. Conversely, the titanium filled polymer coating, especially series 3, having low thickness values, has higher hardness values. Table 9 shows the results of the combined polymer coating thickness determination. Table 9 Thickness measurement results of combined polymer coatings, µm Solution Series 1 Series 2 Series 3 5% NaCl 0.294 0.389 0.349 5% H2SO4 0.300 0.383 0.267 10% H2SO4 0.415 0.527 0.409 5% КOH 0.236 0.472 0.379 10% КOH 0.177 0.492 0.313 Medium 0.284 0.453 0.343 S o u r c e: made by A. Yepaneshnikova According to Table 9, the combined polymer coating of series 2 has the maximum thickness values, which also performed well in aggressive media. Series 3 combined polymer coating with poor resistance to aggressive media has average thickness values. The combined polymer coatings of series 2 and 3 had higher thickness, which means that their initial formulation shall be taken into consideration. The combined polymer coating had a low viscosity when it was created, and initially already had a low thickness. Thus, the technology of protective coatings of a new composition used for metallic and non-metallic products operating in aggressive media was developed. The new formulation of developed polymer protective coatings favorably distinguishes the proposed composition from the existing ones. 4. Conclusion 1. The formulation of corrosive polymer coating with various fillers for protection of metal structures and products from the harmful effects of corrosion was developed. The behavior of different polymer coatings in aggressive media (acidic, neutral, and alkaline) with fillers of microsilica, titanium dioxide and their combination were also considered. 2. It was found that the polymer coating with microsilica filler performed well in acidic environments (5 and 10% H2SO4), while the polymer coating with titanium dioxide filler performed well in hydrochloric (10% NaCl) and alkaline (5 and 10% KOH) environments. 3. The best performance was achieved by the combined polymer coating series 2, which performed well in hydrochloric and acid solutions, worse in alkaline solutions (corrosion score 2-4). This is due to the presence of styrene in the composition of the combined coating, which has good resistance to aggressive media. 4. The use of production waste as secondary raw materials coming from electrothermal, metallurgical, coke and chemical industries will serve as a basis for the creation of new production in order to strengthen and develop the economy and will reduce the environmental load, as well as reduce the area of storage of production waste.

About the authors

Vladimir V. Merkulov

Karaganda Industrial University

Email: smart-61@mail.ru
ORCID iD: 0000-0003-0368-3890

Candidate of Chemical Sciences, Associate Professor of the Department of Chemical Technology and Ecology

Temirtau, Kazakhstan

Gulnara A. Ulyeva

Karaganda Industrial University; Qarmet JSC

Email: g.ulyeva@mail.ru
ORCID iD: 0000-0002-3600-1318

Candidate of Technical Sciences, Associate Professor, Leading Specialist of the Laboratory of Metallurgy and Flaw Detection of the Center for Analytical Control of Qarmet JSC

Temirtau, Kazakhstan

Anastasia A. Yepaneshnikova

Karaganda Industrial University

Email: aae9909@mail.ru
ORCID iD: 0009-0004-8295-1367

graduate student of the Department of Metallurgy and Materials Science

Temirtau, Kazakhstan

Irina E. Volokitina

Karaganda Industrial University

Author for correspondence.
Email: irinka.vav@mail.ru
ORCID iD: 0000-0002-2190-5672
SPIN-code: 8965-4704

PhD, Professor of the Department of Metallurgy and Materials Science

Temirtau, Kazakhstan

References