Papers by Keyword: Protective Coating

Abstract: Concrete structure especially that exposed to aggressive environment is deteriorated leading to damage of concrete buildings. Concrete coating is one of the most effective methods used for concrete protection. In this work epoxy was modified with nanosilica (NS) with different loadings. Epoxy nanosilica (EP-NS) composite was formulated and used as concrete protective coating after evaluate its properties regarding drying time, dry film thickness (DFT), adhesion strength. The coated concretes ware tested as; water absorption, contact angle (hydrophobicity) and chloride diffusion resistance by ion exchange method. Although, durability of coated concretes were examined by determining change in weight and change in compressive strength after immersion in both sulfuric acid and sodium chloride solution separately. The study revealed that, the optimum NS content is 3 % by total weight of coating. The prepared EP-NS coatings have significant protection mechanism for enhancing concrete performance against the postulated aggressive attack. Keywords: protective coating, polymer nanocomposite coating

Abstract: In this study, we research the long-term UV protective effect of BNNSs/PVB multilayer thin film coating on the properties of extra virgin olive oil. Boron nitride nanosheets (BNNSs) were synthesized using the liquid exfoliation method. BNNSs/PVB multilayer thin film was coated on tubes by dip-coating. After the UV irradiation of coated and uncoated glass tubes at different times, the total phenol content (TPC) and antioxidant activity of olive oil (TAA) were determined. Specific absorption coefficients K232 and K270 in the ultraviolet region were measured for estimating the oxidation degree of olive oil after irradiation. Free fatty acid (FFA) in olive oil after UV irradiation was determined by the titration method. Olive oil quality analysis indicates that BNNSs/PVB coating on the glass is effective on the protection of TPC and TAA of olive oil. In addition, the results show that extra virgin olive oil in the coated glass tube is maintained nearly 2 times more than the amount of phenol in the uncoated tube. While olive oil samples in glass tube coated with 30 and 50 times exceeded the limit of K270 value (0.22) after 400 hrs, it was determined that olive oil samples in uncoated glass exceeded this limit after 215 hrs. After 720 hours of UV irradiation, the free fatty acid value of the UCOL (uncoated) sample increased by 24.7% compared to the initial value, while the increase in the COL50 (coated) sample was 15%.

Abstract: The work is devoted to the actual problem of corrosion of the gas-collecting bell of the Soderberg electrolysis cell, which operates in close proximity to the molten electrolyte. Due to gas corrosion during the operation of the electrolysis cell, the cast-iron sections are destroyed and the release of anode gases into the atmosphere of the housing occurs. Iron-containing corrosion products falling into the melt of primary aluminum reduce its quality and grade. In order to prevent this phenomenon, the effectiveness of their protection with a dry mixture for obtaining a protective oxide-ceramic coating of cast-iron surfaces of gas-collecting bell is studied. The results obtained proved the effectiveness of the proposed coating: the service life of the gas-collecting bell sections increased by 4 times. After applying the protective coating for A85 grade aluminum, it increased from 2 to 24%, and the share of A7 grade aluminum decreased from 25 to 18 %.

Abstract: The article examines the hardness of the coating made of PG-CP4 powder. Plasma powder deposition was performed to samples made of 40H13 steel and then the samples treated with a laser beam. A multi-factor model was established that relates the hardness of the protective coating to the radiation power W, the longitudinal feed Spr of the laser beam, and the distance L from the protective casing of the laser head to the treated surface. Depending on the laser treatment modes, coating was in a state of complete, partial reflow or its absence. Full reflow is characterized by the adhesion of the filler material to the substrate, by maximum hardness of HRC 51.2–56.6 and no defects. In the absence of reflow, gas sinks, transverse microcracks, detachments, and other defects were found in the coating material, and the hardness decreased to HB 125–212. An increase in W and a decrease in Spr lead to increases the hardness of the treated coating, which is explained by an increase in the specific heat flux supplied to the coating per unit time, and a high rate of heat removal deep into the surface layer of 40H13 steel. The thickness of the surface layer with increased hardness ranged from 0.1 to 1.5 mm. Based on the multi-factor model, laser processing modes are controlled to ensure the required values of the protective coating hardness. The research results are recommended for use in enterprises that implement laser technologies and develop modern laser systems.

Abstract: The article presents testing of polymer protective coating based on polyurethane developed in Bauman Moscow State Technical University. It is shown that the developed coating has an increased resistance to erosive wear, an increased level of adhesion and temperature resistance, compared with the existing coatings, certified by aviation.

Abstract: The paper presents data of experimental research into the importance of protective surface coatings in welded products for MMA stability; heat field distribution patterns on their surfaces, and structure and phase composition of the welded metal. The study has revealed that a protective surface coating in a welded item in MMA has a positive effect on shortcut duration, increasing it by 5-11 %, raising its formation and transformation time by 10-12 %; 15% dimensional increase of a welded metal grain is registered as well, and a heat impact zone expands by 25%.

Abstract: This article deals with the issues of assessment of wear resistance of multifunctional coats used in the manufacture of art and industrial products. The article shows that in the production process of such products protective&decorative coatings are widely used. They must possess a complex of features, among which wear-resistance occupies a front place. To determine this parameter, the authors developed a special technique for accelerated testing and upgraded the test benches, which makes it possible to assess the abrasion resistance of multifunctional coatings. Reliable results were achieved by increasing the accuracy of recording equipment with the use of information technologies. Implemented modernization of the test benches allowed increasing the efficiency and reliability of the test results, as well as provided the expansion of the functional capabilities due to the maximum approximation of the test conditions to the real operating conditions of the art and industrial products. The developed technique of the accelerated testing allows assessing the resistance to abrasion of multifunctional coatings and thereby predicting the service life of the product for artistic and industrial purposes.

Abstract: The normative documents of Ukraine (DBN V.1.1.7 ̶ 2016) [1] establish that the limit of fire resistance of reinforced-concrete building structures is determined by the calculation method or by fire tests, and shall be at least 45 minutes. Taking into account the modern construction technologies, namely, the reduction of the section of the main building reinforced-concrete structures, it is expedient to use fire-retardant coatings to provide the necessary fire resistance limit.

Abstract: The provision of certain information regarding the surface layer of the equipment parts is one of the critical issues for the modern mechanical engineering. The development of new technologies of protective-strengthening treatment of critical parts surface requires the development of improved methods for surface layer material state assessment as a result of high-energy impact typical for ion-plasmatic, ion-implantation and combined treatment method. Moreover, the peculiarities of industrial mechanical engineering production require the development of simple and efficient methods of surface layer parameters checkout. The application of protective coatings complicates the use of universal method of the parts surface layer parameters assessment. The present article is devoted to the development and studying of a new method for the parts surface layer state assessment after its treatment of various types, including the protective-strengthening technologies and the application of protective coatings. The specific features of the proposed assessment method are its simplicity, reliability, and universality.

Abstract: Crude petroleum storage and transportation systems suffer from constant physical stress caused by chemical attack of crude petroleum on its structure. Ceramics are materials with high chemical stability in hostile environment and therefore can be used as an inert coating material. In the present work we have produced Al2O3-Y2O3-ZrO2 composites with high mechanical strength, through thermo-mechanical processing. To evaluate the quality of materials developed and the possibility of using them as inert protective coatings, storage and transportation systems, we have studied the physic-chemical and mechanical stability of these materials in crude petroleum originated from onshore and offshore. Structural, microstructural and mechanical tests showed that 15-20wt% ZrO2 composite ceramics with 2 wt% of Y2O3 additives presented better results in terms of mechanical hardness and microstructural characteristics. The study of stability of composite ceramics in crude petroleum environment showed that ceramics did not present any additional phase except the constituent phases. Result of microscopy and Vickers hardness tests also showed that there is no visible change in these characteristics after even 90 days of submersion in crude petroleum. Thus we conclude that composite ceramics could be potential materials for inert coating in crude petroleum environment.