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1

Effect of Fe and Mn on corrosion resistance of recycled self-hardening AlZn10Si8Mg alloy

Mikolajčík Martin, Tillová Eva, Kuchariková Lenka, Šurdová Zuzana

Production Engineering Archives

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2025

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Vol. 31, Iss. 1

54--64

EN

Recycled aluminium alloys are a highly valued alternative for manufacturers, particularly in the automotive and aerospace industries, due to increasing demands on the environmental performance and sustainability of the industry. Self-hardening aluminium alloys, which achieve the required mechanical properties without heat treatment, enable the emissions generated by production to be reduced even further. In addition to an advantageous strength-to-weight ratio and excellent machinability, corrosion resistance in a variety of environments is also important in most applications of aluminium alloys. Repeated recycling cycles negatively influence the quality of aluminium because of an increase in iron content, which is considered an impurity. This is due to the formation of intermetallic phases which negatively affect the mechanical, fatigue and corrosion properties. In this paper, the effect of Fe and Mn on the microstructure and corrosion resistance of self-hardening recycled AlZn10Si8Mg alloy was investigated using the AUDI test, atmospheric long-terming test and 3.5% NaCl solution test. The corrosion mechanism was subsequently determined by sectioning the samples. Alloy A with the lowest iron content exhibited the best corrosion behaviour, as it was subjected to only localised forms of corrosion even in the aggressive environment of the AUDI test. In this environment, the other alloys were attacked by general corrosion of the entire surface. Manganese alloying caused a subtle improvement in the corrosion resistance of alloy D but was limited by the high porosity. The eutectic and intermetallic phases corroded the most, while the alpha phase was more resistant.

2

Three-layer Repair Coating System for Manholes, Pump Stations, and Tanks in Aggressive Sulfate Environment

Pawlak Tomasz, Szymczak-Graczyk Anna, Garbowski Tomasz

Civil and Environmental Engineering Reports

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2025

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Vol. 35, no. 1

1--19

EN

Advancements in the repair and protection of water and wastewater infrastructure are now focused on using an innovative material called polyurea. Distinguished by its rapid curing time and versatile applications, polyurea is applied using a spray gun with high-pressure pumps. The introduction of new building materials is part of ongoing efforts to meet stringent environmental, health, and performance standards, and polyurea offers significant improvements by eliminating solvents and volatile organic compounds (VOCs). This paper presents a technological protocol starting with inspection and cleaning, followed by drying, and ending with the application of three layers: a moisture-blocking base layer, a rigid polyurethane middle layer for structural reinforcement, and a final sealing and anti-corrosion layer. This innovative method ensures a homogeneous, seamless structure, enhances construction durability, and accelerates the repair process, allowing immediate resumption of operation. Designed specifically for aggressive wastewater environments, this system is characterized by excellent corrosion resistance, making it ideal for water and wastewater infrastructure elements such as reinforced concrete manholes, sewage pumping stations, and tanks. Customizable polyurea properties allow personalization based on environmental aggressiveness, structure size, and abrasion resistance, representing a significant advancement in infrastructure maintenance technology. The paper showcases this modern repair and renovation method, highlighting its applications, benefits, and potential to revolutionize water and wastewater infrastructure maintenance in challenging conditions. The effectiveness of this solution is also compared with traditional methods, demonstrating the superiority of the three-layer system in terms of waterproofing, sulfuric acid resistance, monolithic structure, and application time.

3

Effect of solution annealing on corrosion resistance of austenitic stainless steels in chloride-containing environment

Zatkalíková Viera, Markovičová Lenka, Uhríčik Milan, Slezák Martin

System Safety : Human - Technical Facility - Environment

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2024

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Vol. 6, iss. 1

421--429

EN

Austenitic stainless steels are highly corrosion-resistant in common oxidation environments. However, aggressive chloride-containing solutions can evoke local corrosion, which performs an important risk in the safe use of these materials. This research deals with the effect of the solution annealing (1050 °C, 15 min) on the electrochemical parameters of AISI 304 and AISI 316L stainless steels. Corrosion resistance of the solution-annealed specimens is evaluated and compared to the as received specimens by the potentiodynamic polarization test performed in 1M pH neutral NaCl solution at the 20 ± 3 °C temperature. The obtained results did not clearly confirm the positive effect of solution annealing on corrosion resistance in the given aggressive solution. Although the pitting potentials indicating higher pitting corrosion resistance increased, the kinetics of the corrosion process intensified.

4

Study of waterproof ability and corrosion resistance of basalt fiber‑reinforced concrete with superhydrophobic surfaces

Li Yunfeng, Wang Qing, Hou Chen, Song Qingnan, Zhang Rui, Wang Ning

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e93, 2024

EN

Basalt fiber-reinforced concrete (BFRC) is used extensively in bridge engineering. However, seawater can cause the cracking of BFRC bridge concrete and the corrosion of steel reinforcement inside the concrete. In this study, an efficient fabrication method of the superhydrophobic surface of BFRC was used to improve its durability. BFRC has high surface compactness, and sodium stearate can play a better role as a modifier. Through the orthogonal study, superhydrophobic BFRC was prepared, and the effects of three major factors (temperature, time, and concentration) on the wettability of BFRC were investigated. The soaking time and solution concentration were more significant than any other factor. The capillary water absorption of the superhydrophobic BFRC was reduced compared to the BFRC. In addition, the soaking method could improve BFRC corrosion resistance by analyzing the equivalent circuit. The soaking method could improve the durability of BFRC effectively. Meanwhile, BFRC with a superhydrophobic surface had self-cleaning performance and good mechanical robustness. This research extends the scope and field of BFRC and provides technical support for utilizing the existing building.

5

Effect of heat input in dissimilar friction stir welding of A390-10 wt.% SiC composite–AA2024 aluminum alloy

Aval Hamed Jamshidi

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 3

art. no. e172, 2024

EN

This study investigates the impact of heat input, generated during friction stir welding, on the microstructure, mechanical properties, and corrosion resistance of dissimilar joints between A390-10 wt.% SiC composite and AA2024-T6 aluminum alloy. Welds were created using two rotational speeds: 600 rpm and 1600 rpm, while maintaining a constant traverse speed of 60 mm/min and employing a triangular pin tool. The results reveal that increasing the heat input from 125 to 354 J/mm leads to enhanced mixing in the stir zone, resulting in the formation of a layered structure. The stir zone area increases by 23% with the rise in heat input from 125 to 354 J/mm. Moreover, as the heat input and plastic strain in the stir zone increase, the particle size decreases by 31%, and their distribution becomes more uniform. Furthermore, an increase in heat input leads to the formation of coarser precipitates and particles on both the advancing and retreating sides, regardless of the type of precipitates formed. Conversely, reducing the heat input from 354 to 125 J/mm results in achieving maximum hardness (165.3 ± 2.3 HV0.1), yield strength (410.3 ± 11.3 MPa), ultimate tensile strength (514.5 ± 10.4 MPa), and minimum corrosion rate (0.41 mm/year).

6

The influence of carbide reinforcement on the properties of sintered aluminium alloy matrix composites

Szewczyk-Nykiel Aneta

Technical Transactions

|

2023

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Vol. 120, iss. 1

art. no. e2023005

EN

Based on the commercial aluminium alloy powder blend (Alumix 431D) metal matrix composites reinforced with particles of SiC as well as TiC were produced by conventional powder metallurgy technology and the effect of the type and amounts of reinforced particles on the selected properties and microstructure of sintered composites were investigated. In particular, the densification behaviour, the wear resistance and the corrosion resistance in 3.5% NaCl solution were identified. It was stated that both the type and the weight fraction of carbide used as particulate reinforcement have a great impact on the properties of aluminium alloy matrix composites. It was shown that the introduction of titanium carbide has a more favourable effect on the properties of sintered Alumix 431D matrix composites in comparison to silicon carbide and the optimum content of TiC in composite is 4 wt. % due to the highest hardness, wear resistance (wear rate of 2.865·10 ̄ ³ mm³/m) and simultaneously the best corrosion resistance (corrosion rate of 0.005 mm/year).

7

Paint coatings in military applications general characteristics

Michalski Marek

System Safety : Human - Technical Facility - Environment

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2023

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Vol. 5, iss. 1

285--293

EN

The article presents an overview of research conducted on the development of camouflage coating systems in the range of ultraviolet, visible, near infrared and radar waves, as well as operational tests of these systems. Among other things, the influence of temperature on coating systems and tests in chambers with cyclically changing conditions is presented.

8

Properties of WC-Co coatings with Al2O3 addition

Radek Norbert

Production Engineering Archives

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2023

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Vol. 29, Iss. 1

94--100

EN

Properties of WC-Co coatings with Al2O3 addition on the C45 mild steel surface in acidic chloride solution were examined. The WC-Co-Al2O3 coatings on steel surfaces were deposited by an electro-spark (ESD) technique. The anti-corrosion properties of the coatings were mainly investigated by electrochemical methods. Moreover, the scanning electron microscope (SEM) was employed for the observation of the surface of materials. The structure of coatings depended on the composition of electrospark electrodes. In the WC80-Co5-Al2O315 coating, the largest corrosion resistance was shown. The corrosion rate of the specimen was approximately eight times smaller than the coating with out of Al2O3 addition. The aim of the research was to obtain, by adding alumina, an improvement in the functional properties of WC-Co coatings produced by the ESD method. Due to the original features of ESD coatings, they can be used in sliding friction pairs and as anti-wear coatings on cutting tools. C-Co coatings with AlO3 addition.

9

Zinc and graphene oxide composites as new protective coatings for oil and gas pipes

Asghar M. Sajid Ali, Amir Muhammad, Hussain Umer, Sabri Mohammed M.

Polimery

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2023

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Vol. 68, nr 7-8

378--385

EN

A method was developed to obtain a durable coating consisting of zinc and graphene oxide (Zn-GO) in order to reduce the mechanical wear and tear rate of oil and gas pipelines made of steel. Graphene oxide was obtained from graphite by wet chemical oxidation (unmodified and modified Hummers’ method) using potassium permanganate and sulfuric acid. The process was carried out at various temperatures. The steel was covered with an ultrathin layer of Zn-GO using the electrophoretic deposition method. The GO particle size (< 90 nm) was confirmed by XRD and laser analysis. For GO particles obtained by the modified Hummers’ method, a significant correlation was observed in the scratch (R2 = 0.87) and the Vickers microhardness tests (R2 = 0.93), which indicates a lower wear rate of Zn-GO-coated steel.

PL

Opracowano metodę otrzymywania trwałej powłoki składającej się z cynku i tlenku grafenu (Zn-GO) w celu zmniejszenia zużycia mechanicznego rurociągów naftowo-gazowych wykonanych ze stali. Tlenek grafenu pozyskano z grafitu metodą mokrego utleniania chemicznego (niezmodyfikowana i zmodyfikowana metoda Hummersa) z użyciem nadmanganianu potasu i kwasu siarkowego. Proces prowadzono w różnej temperaturze. Stal powlekano ultra cienką warstwą Zn-GO techniką osadzania elektroforetycznego. Metodą XRD i analizą laserową potwierdzono wielkość cząstek GO (≤ 90 nm). Dla cząstek GO otrzymanych zmodyfikowaną metoda Hummersa zaobserwowano znaczącą korelację w teście zarysowania (R2 = 0.87) i mikrotwardości Vickersa (R2 = 0.93), co świadczy o mniejszym stopniu zużycia stali pokrytej powłoką Zn-GO.

10

Investigations of CrN/TiO2 coatings obtained in a hybrid PVD/ALD method on Al-Si-Cu alloy substrate

Staszuk Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144622

EN

The paper addresses an important scientific topic from the utilitarian point of view concerning the surface treatment of Al-Si-Cu aluminum alloys by PVD/ALD hybrid coating deposition. The influence of the conditions of deposition of titanium oxide in CrN/TiO2 coatings on their structure and properties, in particular corrosion resistance, were investigated. The TiO2 layer was produced by the atomic layer deposition (ALD) method with a variable number of cycles. Structural investigations were performed using scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), and Raman spectroscopy methods. Electrochemical properties were analyzed using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. The CrN/TiO2 hybrid coating with titanium oxide deposited at 500 ALD cycles showed the best corrosion properties. It was also found that the prerequisite for obtaining the best electrochemical properties was the amorphous structure of titanium oxide in the tested hybrid coatings. The high tribological properties of the tested coatings were also confirmed.

11

Influence of annealing conditions on changes of the structure and selected properties of Al88Y7Fe5 and Al88Y6Fe6 alloys

Babilas Rafał, Spilka Monika, Łoński Wojciech, Radoń Adrian, Kądziołka-Gaweł Mariola, Gębara Piotr

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144614

EN

Al-Y-Fe amorphous and nanocrystalline alloys are characterized by a unique collection of diverse properties that are influenced by various factors, including heat treatment. In this paper, the effect of heat treatment on the structural changes and selected properties of Al-Y-Fe metallic glasses in the as-spun state is investigated. The structure of the Al88Y7Fe5 and Al88Y6Fe6 alloys was examined by X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The corrosion resistance of the samples was characterized using polarization tests in a 3.5% NaCl solution at 25 °C. The effect of sodium chloride on the surface was studied with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The magnetic properties of Al-based alloys were explored using a vibrating sample magnetometer (VSM). It was revealed that the tested alloys show better properties after annealing than in the as-spun state. The annealing of the Al88Y7Fe5 and Al88Y6Fe6 alloys in the temperature range of 200 to 300 °C improved the magnetic properties and corrosion resistance of these materials. After 3,600 s, the better EOCP values were recorded for the Al88Y6Fe6 and Al88Y7Fe5 alloys after annealing at 300 °C and 200 °C, adequately. On the basis of the polarization tests, it was concluded that the electrochemical properties are better for Al88Y6Fe6 alloys after annealing at 300 °C.

12

Effect of spray distance on the microstructure and corrosion resistance of WC - based coatings sprayed by HVOF

Jonda Ewa, Łatka Leszek, Maciej Artur, Godzierz Marcin, Gołombek Klaudiusz, Radziszewski Andrzej

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144610

EN

Cermet coatings provide protection against aggressive operating environment of machine and device elements, such as corrosion, wear or high-temperature conditions. Currently WC-based cermet coatings are frequently used in the different industry branches. In this work, conventional WC-based powders (WC-Co and WC-Co-Cr) were sprayed with High Velocity Oxy Fuel (HVOF) onto AZ31 magnesium alloy with different spray distances (320 and 400 mm). The aim of the research was to investigate the effect of the spray distance on the microstructure of the coatings, phase composition and electrochemical corrosion resistance. Results revealed that higher spray distance results in greater porosity, 1.9% and 2.3% for 320 mm and 2.8% and 3.1% for 400 mm in case of WC-Co and WC-Co-Cr coatings, respectively. Also the influence has been observed for coatings microhardness, c.a. 1300 HV0.3 for shorter spray distance, whereas for longer one it was less than 1100 HV0.3. The corrosion resistance estimated in potentiodynamic polarization measurements was the best for WC-Co-Cr coating deposited from the shorter spray distance, corrosion current density was equal to 2.9 µA·cm-2 and polarization resistance was equal to 8424 Ω∙cm2.

13

Automated fabrication of heat exchangers used in process vessels

Dec Andrzej, Orłowicz Antoni W.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2023

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Vol. 67, No. 4

28--33

EN

The article presents issues concerning the fabrication of coil heat exchangers on process vessels used in process lines of the food industry. Previously commonly fabricated shell tube exchangers, containing spot field welds, are susceptible to corrosion, the formation of sediments and implosion. In addition, such exchangers are sensitive to the high pressure of heating and cooling medium. The use of C-channel-shaped heat exchangers on the external surface of the vessel shell constitutes an innovative solution characterised by lower corrodibility and higher resistance to the pressure of medium and sediment formation. The research work discussed in the article concerns the above-presented solution and an automated station enabling the fabrication of innovative coil heat exchangers.

PL

W artykule przedstawiono problematykę dotyczącą wytwarzania wężownicowych wymienników ciepła w zbiornikach procesowych, pracujących w liniach technologicznych stosowanych w przemyśle spożywczym. Dotychczas powszechnie wytwarzane płaszczowe wymienniki ciepła, z uwagi na zastosowanie punktowych spoin montażowych, wykonanych ręcznie metodą TIG, są podatne na procesy korozyjne i tworzenie się osadów oraz zjawisko implozji. Ponadto są wrażliwe na podwyższone poziomy ciśnienia medium grzewczo-chłodzącego. Zastosowanie wymienników ciepła o profilu ceownika na powierzchni zewnętrznej płaszcza zbiornika jest innowacyjnym rozwiązaniem cechującym się mniejszą podatnością na korozję oraz większą odpornością na ciśnienie medium i tworzenie się osadów. Niniejsza praca dotyczy takiego właśnie rozwiązania oraz zautomatyzowanego stanowiska do jego wykonania.

14

Study on the anti-corrosion properties of hydrophobic cement mortar containing coral sand

Zhao Yayun, Wang Qing, Song Qingnan, Xu Shuangshuang

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e177, 2023

EN

The high porosity and strong water absorption of coral sand (CS) lead to the decline of the corrosion resistance of CS cement mortar. In this study, an environmentally friendly method of preparing hydrophobic concrete with water-repellent and anti-corrosion properties using CS is proposed. CS was modified by stearic acid to reduce the excessive water absorption caused by its high porosity. The prepared modified CS (M-CS) was used to partially replace the sand in the cement mortar to fabricate hydrophobic cement mortar, the water contact angle of which was found to be 115.9°. The cumulative water absorption, compressive strength, and anti-corrosion properties of hydrophobic cement mortar were explored. The cumulative water absorption of the hydrophobic mortar was found to be 49.75% lower than that of ordinary cement mortar. The compression test results show that a 10% content of M-CS can improve the compressive strength of cement mortar. Moreover, the corrosion resistance was found to be enhanced with the increase of the M-CS content. The hydrophobic cement mortar developed in this study is expected to strengthen the corrosion resistance of cement mortar used for coastal engineering.

15

Microstructure and properties of AlCr and AlCrFe coatings deposited by magnetron sputtering

Ura-Bińczyk Ewa, Kulikowski Krzysztof, Chromiński Witold, Smolik Jerzy, Lewandowska Małgorzata

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e140, 2023

EN

In this work, AlCr and AlCrFe coatings were deposited via magnetron sputtering on technical substrates of carbon steel C45 and titanium grade 2. The coatings feature an amorphous structure, a thickness of 3-4 μm, and are uniform in terms of thickness and chemical composition. No major defects were visible at the interface; however, there is no diffusion at the interface, which indicates the adhesive type of bonding and results in relatively low adhesion. The coatings are characterized by a hardness of about 8-10 GPa and a Young modulus above 150 GPa. Both values are slightly higher for steel substrate. The coatings assure good corrosion resistance for steel substrate while underperforming those of Ti grade 2.

16

Polimery w nowym wcieleniu

Wróbel Gabriel

Polimery dla Biznesu

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2022

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nr 4

27--29

PL

W artykule przedstawiono studium produktów przemysłowych – sprężyn pierścieniowych, które dzięki nowym rozwiązaniom materiałowym pozwalają poszerzyć obecnie stosowane charakterystyki podobnych elementów konstrukcyjnych wykonywanych z wysokojakościowych stali [1-4]. Własności materiałów polimerowych, w połączeniu z odpowiednio dobraną postacią konstrukcyjną oraz wymiarami, stwarzają szerokie pole dla zastosowań w układach zarówno statycznych jak i dynamicznych, dzięki możliwościom spełnienia różnych kryteriów użytkowych, obejmujących sztywność, deformację, tłumienie drgań, uderzeń, hałasu. Oferują jednocześnie właściwe polimerom zalety odporności na korozję, technologiczności, ale również gęstość masową w porównaniu do stali.

EN

The article presents a study of industrial products - ring springs, which, thanks to new material solutions, make it possible to expand the currently used characteristics of similar structural elements made of high-quality steels [1-4]. The properties of polymeric materials, combined with appropriately selected structural form and dimensions, create a wide field for applications in both static and dynamic systems, thanks to their ability to meet various performance criteria, including stiffness, deformation, damping of vibrations, impacts, noise. At the same time, they offer the inherent advantages of polymers in corrosion resistance, technologicity, but also mass density compared to steel.

17

The role of the chemical composition of trivalent passivation bath for aluminum 5005A series in shaping the morphology of conversion coating and corrosion resistance

Gralak Eryk, Hoffman Adrianna, Winiarski Juliusz

Ochrona przed Korozją

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2022

|

nr 6

177--181

EN

5005A series aluminum samples were passivated to obtain a conversion coating based on Cr(III) compounds. It was shown that the corrosion resistance of galvanized aluminum in a bath containing both zirconium and cobalt compounds, measured in a 0.05 M NaCl solution, slightly increased compared to the corrosion resistance of aluminum as delivered, i.e. without conversion coating. In the case of galvanic treatment of aluminum in baths containing separately cobalt or zirconium compounds, a significant increase in corrosion resistance was achieved in relation to aluminum in the delivered condition. SEM analysis showed that in the presence of the simultaneous addition of zirconium and cobalt compounds, the most developed surface was created compared to the addition of only zirconium, where bright spheroidal precipitates occur locally. EDS analysis showed the presence of : C, O, Mg, Al and Si, small amounts of Cr, Zr, F on the surface of the aluminum covered with the Cr + Zr + HF conversion coating. During measurements with the use of the linear polarization resistance (LPR) technique, the best anti-corrosion properties were demonstrated by the samples that were passivated in a Cr(III) solution with the addition of Zr compound and HF and in a Cr(III) solution with the addition of Co compound and HF.

PL

Próbki aluminium serii 5005A poddano procesowi pasywacji z wytworzeniem powłoki konwersyjnej na bazie związków Cr(III). Wykazano, że odporność korozyjna aluminium poddanego obróbce galwanicznej w kąpieli zawierającej jednocześnie związki cyrkonu i kobaltu, mierzona w 0,05 M roztworze NaCl, nieznacznie wzrosła w stosunku do odporności korozyjnej aluminium w stanie dostarczenia, tzn. bez powłoki konwersyjnej. W przypadku obróbki galwanicznej aluminium w kąpielach, które zawierały osobno związki kobaltu lub cyrkonu, uzyskano wyraźny wzrost odporności korozyjnej w stosunku do aluminium w stanie dostarczenia. Analiza SEM wykazała, że w obecności jednocześnie dodatku cyrkonu i kobaltu powstała najbardziej rozwinięta powierzchnia. W przypadku zastosowania tylko dodatku cyrkonu jasne wytrącenia sferoidalne występują lokalnie. Analiza EDS wykazała obecność C, O, Mg, Al i Si, niewielkich ilości Cr, Zr, F na powierzchni aluminium pokrytego powłoką konwersyjną Cr + Zr + HF. Podczas pomiarów techniką liniowego oporu polaryzacji (LPR) najlepsze właściwości antykorozyjne wykazały próbki poddane pasywacji w roztworze Cr(III) z dodatkiem związków Zr i HF oraz w roztworze Cr(III) z dodatkiem związków Co i HF.

18

Porównanie mikrostruktury i odporności na korozję powłok natryskiwanych metodą HVOF (high velocity oxy fuel) na podłoże ze stopu magnezu

Jaworska Justyna, Gruszka Magdalena, Nabrdalik Monika, Marcinkowski Marcin, Mikołejko Wojciech, Augustyn Ewelina, Jonda Ewa, Maciej Artur, Kiljan Anna

Ochrona przed Korozją

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2022

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nr 4

112--123

PL

Stopy magnezu ze względu na korzystny stosunek niskiej masy do dobrych własności mechanicznych coraz powszechniej są stosowane w przemyśle. Przeszkodę w ich aplikacji może stanowić reaktywność chemiczna magnezu, a więc jego wysoka podatność na korozję. Powłoki natryskiwane cieplnie metodą HVOF (high velocity oxy fuel) pozwalają wytworzyć szczelną barierę pomiędzy materiałem podłoża a środowiskiem, dzięki czemu mogą stanowić skuteczną ochronę stopów magnezu. W artykule przedstawiono wyniki badań mikrostruktury oraz wybranych własności dwóch powłok natryskiwanych przy wykorzystaniu komercyjnych proszków WC-Co i WC-Cr3C2-Ni metodą HVOF na podłożu ze stopu magnezu AZ91. Celem pracy było porównanie mikrostruktury, wybranych własności oraz odporności na korozję wytworzonych powłok. Na podstawie wyników badań mikroskopowych stwierdzono, że powłoki charakteryzują się zwartą mikrostrukturą, a twarde cząstki WC oraz Cr3C2 są równomiernie rozłożone w całej objętości powłoki. Powłoka WC-Co charakteryzuje się ponadto wyższą odpornością korozyjną oraz mikrotwardością, jednak cechuje ją mniejsza wydajność natryskiwania i chropowatość w porównaniu z powłoką WC-Cr3C2-Ni.

EN

Due to the promising ratio of low weight to good mechanical properties, magnesium alloys are more and more widely used in industry. An obstacle in their application may be the chemical reactivity of magnesium, and therefore its high susceptibility to corrosion. Thermal sprayed coatings with the HVOF (high velocity oxy fuel) method allow creating a tight barrier between the base material and the environment, which can effectively protect magnesium alloys. The article presents the results of research on the microstructure and selected properties of two sprayed coatings with the use of commercial WC-Co and WC-Cr3C2-Ni powders using the HVOF method on the substrate made of AZ91 magnesium alloy. The work aimed to compare the microstructure, selected properties, and corrosion resistance of the produced coatings. Based on the results of the metallographic research, it was found that the coatings are characterized by a dense microstructure, and the hard particles of the WC and Cr3C2 are evenly distributed throughout the entire volume of the coating. Also the WC-Co coating is characterized by higher corrosion resistance and microhardness however, it has a lower spray efficiency and roughness compared to the WC-Cr3C2-Ni coating.

19

Initial comparative studies of the anodic polarization of 304 austenitic steel in eutectic solvents containing propylene or ethylene glycol

Marczewski Marek, Frąckowiak Sandra, Winiarski Juliusz

Ochrona przed Korozją

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2022

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nr 4

103--106

EN

This work presents preliminary comparative studies on the process of electrochemical polishing of austenitic 304 steel in two deep eutectic solvents (DES), based on polyols as hydrogen bond donors. The first is the choline chloride and ethylene glycol solvent, known before in the literature, and the second is the rarely discussed choline chloride and propylene glycol solvent. The analyzes showed that in the latter liquid it is possible to achieve similar results as in the first solvent, but without obtaining a full-fledged effect of electrochemical polishing. The process of anodic polarization in each range of current density for each liquid led to an increase in surface roughness and a simultaneous smoothing of the steel microstructure in the case of tested high current densities. For samples subjected to anodic polarization at medium and high current densities, a slight increase in corrosion resistance was observed compared to the chemically etched steel sample.

PL

W pracy zaprezentowano wstępne badania porównawcze nad procesem polerowania elektrochemicznego stali austenitycznej 304 w dwóch rozpuszczalnikach eutektycznych (deep eutectic solvents, DES) opartych na poliolach jako donorach wiązania wodorowego. Pierwszym z rozpuszczalników był znany w literaturze przedmiotu układ złożony z chlorku choliny i glikolu etylenowego, a drugim – rzadko omawiany układ złożony z chlorku choliny i glikolu propylenowego. Wykazano, że w wypadku ostatniej cieczy można osiągnąć podobne wyniki co w tej na bazie glikolu etylenowego, nie uzyskując jednak wyraźnego efektu polerowania elektrochemicznego. Proces polaryzacji anodowej w każdym zakresie gęstości prądu dla każdej cieczy doprowadził do zwiększenia się chropowatości powierzchni przy jednoczesnym wygładzeniu mikrostruktury stali w wypadku ustalonych wysokich gęstości prądu. Stwierdzono drobny wzrost odporności na korozję próbek poddanych polaryzacji anodowej przy średnich i wysokich gęstościach prądu w porównaniu z próbką stalową trawioną chemicznie.

20

Effect of electrochemical treatment in eutectic solvent and deposition of SiO2 sol-gel coating on corrosion resistance of 316L steel in Ringer’s solution

Mazur-Nowacka Anna, Marczewski Marek, Tylus Włodzimierz, Szczygieł Bogdan, Chęcmanowski Jacek

Ochrona przed Korozją

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2022

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nr 5

152--156

EN

The 316L stainless steel samples were subjected to anodic polarization in a eutectic solvent and then theSiO2 coatings were deposited on them using the sol-gel method. The coatings were prepared from a sol containing TEOS as a precursor and ethanol as a solvent. The obtained samples were exposed in Ringer’s solution. Studies have shown that electrochemical treatment of 316L steel affects both the morphology, topography and roughness of the metallic material. Potentiodynamic tests showed that the best barrier properties after exposure to Ringer’s solution were obtained for 316L steel subjected to electrochemical treatment, additionally covered with a SiO2 coating. The deposition of the three-layer SiO2 coatings reduces the corrosion current density and an increase in the polarization resistance relative to the uncoated 316L steel.

PL

Próbki ze stali nierdzewnej 316L poddano polaryzacji anodowej w rozpuszczalniku eutektycznym, a następnie metodą zol-żel osadzono na nich powłoki SiO2. Powłoki otrzymywano z zolu zawierającego TEOS jako prekursor i etanol jako rozpuszczalnik. Otrzymane próbki eksponowano w roztworze Ringera. Badania dowiodły, że elektrochemiczna obróbka stali 316L wpływa zarówno na morfologię oraz topografię, jak i chropowatość materiału metalicznego. Potencjodynamiczne badania wykazały, że najlepsze właściwości barierowe po ekspozycji w roztworze Ringera uzyskano dla stali 316L poddanej obróbce elektrochemicznej i dodatkowo pokrytej powłoką SiO2. Osadzenie trójwarstwowych powłok SiO2 powoduje zmniejszenie gęstości prądu korozji oraz wzrost oporu polaryzacji względem niepokrytej stali 316L.