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EN
This work presents the possibility of the use of a deep eutectic solvents (DES) in the electropolishing process for 316 austenitic stainless steel, instead of highly aggressive conventional sulphate baths. The main emphasis was on finding some relationships between the anodic polarization parameters of the 316 steel, and its surface morphology, topography and corrosion resistance. It has been shown that an increase in the bath temperature from 25 to 65°C accelerates dissolution kinetics of 316 steel in a DES composed of choline chloride and ethylene glycol. The anodic polarization at a current density 15 mA cm–2 for 5 min resulted in removal of the scratches from previous mechanical polishing. By increasing the current density from 15 to 25 mA cm–2, some visual surface levelling was obtained – austenite grains became visible, and the selective etching of grain boundaries has not been observed. Although the samples after anodic polarization were characterized by Ra = 78 ±27 nm (at 15 mA cm–2) and Ra = 96 ±37 nm (at 25 mA cm–2), so a bit higher than Ra for as-supplied steel (43 ±11 nm), the anodic polarization has increased their corrosion resistance in 0.5 mol dm–3 NaCl corrosive environment. The highest polarization resistance (Rp = 2.1-2.4 MΩ cm2 after 22-24 hrs of exposure) was calculated for the steel polarized at 15 mA cm–2 for 5 min. Increasing the current density from 15 to 25 mA cm–2 did not impair the corrosion resistance and resulted in significant broadening of the passive region of this steel during registering the potentiodynamic polarization curves in 0.5 mol dm–3 NaCl.
PL
W pracy zaprezentowano możliwość użycia rozpuszczalników eutektycznych (deep eutectic solvents, DES) w procesie polerowania elektrochemicznego stali austenitycznej 316, w zastępstwie konwencjonalnych i agresywnych kąpieli siarczanowych. Uwagę skupiono na znalezieniu powiązań między parametrami procesu polaryzacji stali 316 a morfologią powierzchni, topografią i odpornością na korozję. Wykazano, że wzrost temperatury kąpieli z 25 do 65°C wpływa na wzrost szybkości roztwarzania stali 316 w rozpuszczalniku DES złożonym z chlorku choliny i glikolu etylenowego. Polaryzacja anodowa przy gęstości prądu 15 mA cm–2 w czasie 5 min spowodowała wyraźne usunięcie rys powstałych po mechanicznym szlifowaniu powierzchni. Poprzez zwiększenie gęstości prądu z 15 do 25 mA cm–2, uzyskano pewne wizualne wyrównanie powierzchni – ziarna austenitu zostały ujawnione, a jednocześnie nie zaobserwowano selektywnego roztwarzania w obrębie ich granic. Pomimo że po polaryzacji anodowej stal charakteryzowała się chropowatością Ra = 78 ±27 nm (przy 15 mA cm–2) i Ra = 96 ±37 nm (przy 25 mA cm–2), a więc nieco więcej niż wartość Ra w stanie dostarczenia (43 ±11nm), to polaryzacja w rozpuszczalniku DES zwiększyła jej odporność na korozję w 0,5 mol dm–3 roztworze NaCl. Najwyższą wartość rezystancji polaryzacji (Rp = 2.1-2.4 MΩ cm2 po 22-24 godzinach ekspozycji) obliczono dla stali polaryzowanej przy 15 mA cm–2 przez 5 min. Zwiększenie gęstości prądu z 15 do 25 mA cm–2 nie pogorszyło odporności na korozję, a skutkiem tego było poszerzenie zakresu pasywnego w trakcie rejestracji krzywych polaryzacyjnych w 0,5 mol dm–3 roztworze NaCl.
4
EN
The paper describes the method of producing a zinc coating on steel by electro-spark deposition technology. The technology of applying electro-spark zinc to the surface was presented. Microscopic observations and corrosion resistance tests were made. The possibilities of practical application of this type of coatings in the process of repairing zinc coatings, either damaged or with manufacturing defects, were analyzed.
PL
Austenityczna stal nierdzewna jest uważana za materiał o doskonałej odporności na korozję i akceptowalnych właściwościach mechanicznych, zalecany do różnych zastosowań konstrukcyjnych, przemysłowych i biomedycznych. W agresywnych środowiskach chlorkowych jest ona podatna na miejscową korozję wżerową. Oceniono odporność na korozję stali nierdzewnej typu AISI 316Ti o powierzchni pasywowanej kwasem azotowym w kwasowym 1 M roztworze jonów chlorkowych w temp. 22-80°C. Ocenę tę oparto na wynikach ekspozycyjnych testów zanurzeniowych i wynikach elektrochemicznej spektroskopii impedancyjnej (EIS).
EN
Com. Ti-stabilized Cr-Ni-Mo austenitic stainless steel was passivated with HNO₃ soln. and then studied for pitting corrosion in 5% FeCl₃ soln. (pH 1.2) by 24-hours std. immersion test and in 0.9 M NaCl + 0.1 M HCl soln. (pH 1.1) by electrochem. impedance spectroscopy (EIS test) at 22- 80°C. The pits were significantly bigger at 22°C than those at 50°C but the distribution of pitting was markedly lower. The polarization resistance decreased with increasing the temp. The quality of the surface passive film was several times lower at 80°C than at the lower temp.
PL
Od lipca 2018 r. do listopada 2019 r. firma OPTEM wraz z Zakładem Dróg i Mostów Politechniki Rzeszowskiej realizowały projekt badawczy pt. „Innowacyjne prefabrykaty łukowe o podwyższonej trwałości przeznaczone dla budownictwa komunikacyjnego”, którego celem było opracowanie nowego prefabrykatu łukowego optem-ARCH. W rezultacie otrzymano znacząco ulepszony wyrób budowlany charakteryzujący się mniejszym ciężarem oraz podwyższoną odpornością na korozję.
EN
From July 2018 to November 2019, the OPTEM company together with the Department of Roads and Bridges of the Rzeszów University of Technology were implementing a research project „Innovative prefabricated arched components of increased durability for transportation engineering”, the aim of which was to develop a new optemARCH prefabricated arch. As a result, a significantly improved construction product of lower weight and totally corrosion resistant was obtained.
EN
New concepts proposed for processing of dual phase (DP) steels as one of the main classes of advanced high-strength steels (AHSSs) to enhance their mechanical properties (strength–ductility combination) and corrosion resistance were introduced. The current review covers (I) the processing routes to obtain the ferritic–martensitic microstructures, (II) parameters of intercritical annealing (IA) treatment, (III) primary thermomechanical treatments, and (IV) post processing. First, the principal heat treatment methods, i.e., step quenching, intermediate quenching, and intercritical annealing of ferritic–pearlitic steel, as well as the partitioning of manganese were critically discussed. Then, the effects of holding time at the intercritical annealing temperature on the austenitization, grain coarsening kinetics, abnormal grain growth, and volume fraction of martensite were summarized. Next, the importance of cold deformation (notably rolling) and heating rate for the development of fine-grained DP microstructures (with chain-networked martensitic islands) through recrystallization and modification of the preferred nucleation sites for the austenite phase was discussed. Moreover, the applications of severe plastic deformation techniques (such as constrained groove pressing), thermal cycling (multi-step or repetitive intercritical annealing), and spheroidization heat treatment were discussed. Finally, the impacts of tempering, quench aging, and bake hardening on the properties of DP steel were reviewed. This short overview shows the opportunities that the conventional and innovative processing routes can offer for the potential industrial applications of DP steels, especially in the lightweight car body for the automotive industry to address the safety, fuel consumption, and air pollution issues.
8
Content available remote Development in PTA surface modifications – a review
EN
Surface modification is one of the most intensively studied issue of technology, which is related to the almost all branches of industry. Since more than 100 years the huge number of methods has been developed and are still in growth. On this field the plasma transferred arc (PTA) hardfacing and surfacing is one of the most frequently used group of the method. The development of this method is going in three ways: (i) modification of the classic technique and the equipment, (ii) development in new materials, especially with the nanometric size and (iii) replacement dangerous materials (e.g. high cobalt alloys). In the current article the state of the art as well as the development directions of the plasma hardfacing issues are described.
EN
Paper discusses results of experimental research aimed at developing of an anti-graffiti paint system for passenger rail vehicles which fulfill the requirements of coating flammability characteristics according to EN 45545-2+A1:2015-12. The most important element of effective fire protection is the use of fire-resistant materials limiting the spread of fire and smoke in rolling stock. Coating system has to meet requirements in the field of fire properties with maintaining the desired performance parameters, such as protective and decorative properties. The development works that are the subject of this article were started by testing standard coating system flammable properties. Next stage of research was to modified fire properties of polyester putty. The tests have shown the effectiveness of the use of a protective paint that allows meeting the requirements in the field of fire safety. In addition, measurements of the corrosion resistance of anti-graffiti coatings were made.
10
PL
Stopy magnezu zyskują coraz większe zainteresowanie ze względu na dobry stosunek własności wytrzymałościowych do ciężaru właściwego. Czysty magnez jest miękkim metalem, nieodpornym na korozję i aby poprawić jego własności mechaniczne i antykorozyjne, stosuje się wiele różnych dodatków stopowych. Jednym z głównych dodatków stopowych w stopach magnezu jest aluminium.
PL
Zastosowanie stali austenitycznych w różnych gałęziach przemysłu ciągle wzrasta, co wynika z ich unikalnych właściwości mechanicznych, plastyczności i odporności na korozję. Powoduje to, że w środowisku agresywnym uzyskuje się wysoką trwałość przez wiele lat i możliwość ograniczenia ciężaru wyrobu.
12
Content available Characterization of Ca50Mg20Zn12Cu18 Alloy
EN
The Ca50Mg20Zn12Cu18 was assessed with different methods in order to characterize its basic characteristics, and to determine whether the amorphous alloy of such composition would be applicable as an implant material. The XRD analysis was conducted to conclude the structure of the initial material. The Ca50Mg20Zn12Cu18 ingot sample demonstrates crystalline structure containing two main intermetallic phases, however as-cast plates show features of an amorphous material, revealing the characteristic amorphous halo on the x-ray patterns. It was confirmed by the scanning electron microscopy method and fracture images revealing chevron pattern morphology with shell type fracture. Corrosion resistance, was studied using the potentiostatic analysis. The amorphous samples show higher resistance than the crystalline one. Post corrosion surface of the Ca50Mg20Zn12Cu18 alloy exhibits high concentration of magnesium and calcium hydroxides, forming the globular structures in large aggregates of spherical units.
13
Content available Biodegradable polymer coatings on Ti6Al7Nb alloy
EN
The aim of the study was to determine the influence of long term exposure to Ringer’s solution of biodegradable polymer coatings containing an active substance on the Ti6Al7Nb alloy substrate on the physical and chemical properties of the coatings and the degradation process of the metal substrate. The studies used poly(L-lactide-co-trimethylene carbonate) P(L/TMC), poly(L-lactide-co-trimethylene carbonate-glycolide) P(L/TMC/G) and poly(D,L-lactide-glycolide) (PLGA) coatings applied to the anodically oxidized Ti6Al7Nb alloy by means of dipping method (1, 2 and 3 dips). The polymer coatings contained ciprofloxacin. Roughness and wettability tests were carried out on the substrate and polymer coatings, the pitting corrosion resistance of the substrate and samples with polymer coating was determined, the number of metallic ions released to the solution from the coated and uncoated samples was determined as well as the adhesion of polymer coatings. The research was supplemented by microscopic observations. The results of the research indicate different influence of exposure to Ringer’s solution on the physical and chemical properties of biodegradable polymer coatings containing ciprofloxacin and the course of the degradation process of the metal substrate.
EN
TiC particle-reinforced AISI 316L stainless-steel matrix composites were prepared using conventional powder metallurgy technology. The effect of TiC content on the microstructure and properties of these composites has been investigated with a particular emphasis upon hardness, wear resistance and corrosion resistance in sea water environments. The results showed that TiC particle reinforcement improved the hardness, wear resistance and corrosion resistance of AISI 316L stainless steel. The higher TiC content in the studied composites resulted in a higher hardness of the wear surface and a lower wear rate. The best corrosion resistance in sea water was achieved for sintered AISI 316L – 5% TiC composite.
PL
Konwencjonalną technologią metalurgii proszków wytworzono umacniane cząstkami TiC kompozyty o osnowie austenitycznej stali AISI 316L. Dokonano oceny wpływu udziału cząstek TiC na mikrostrukturę i właściwości tych kompozytów, w szczególności twardość, odporność na zużycie ścierne i odporność na korozję w środowisku wody morskiej. Stwierdzono, że umocnienie cząstkami TiC doprowadziło do poprawy twardości, odporności na zużycie ścierne i odporności na korozję stali AISI 316L. Wraz ze wzrostem udziału TiC w badanych kompozytach wzrastała twardość powierzchni zużycia, a malała jej szybkość. Natomiast najlepszą odporność na korozję w wodzie morskiej wykazał spiekany kompozyt AISI 316L – 5% TiC.
PL
Dwufazowe stale ferrytyczno-austenityczne typu duplex wykazują doskonałą kombinację właściwości mechanicznych i odporności na korozję, w tym szczególnie agresywną korozję wżerową w środowisku chlorkowym. Pomimo wiedzy i doświadczenia zdobytego podczas spawania tych stopów aktualnie nadal obserwuje się problemy ujawniane w trakcie badań korozyjnych. Dobrze uzasadniony termin „dobra spawalność” odnosi się wyłącznie do grupy cech technologicznych ułatwiających łączenie elementów metalowych przez spawanie, ale nie oznacza automatycznie wysokiej odporności na korozję połączeń spawanych, która w środowisku chlorków osiąga tylko 50÷80% materiału rodzimego. W artykule zostały omówione wszystkie czynniki metalurgiczne oraz technologiczne mające wpływ na końcowe właściwości korozyjne złączy spawanych.
EN
Two-phase ferrite-austenitic duplex stainless steels demonstrate excellent combination of strength and corrosion resistance including particularly aggressive pitting corrosion in chloride environment. The use of duplex and super-duplex stainless steels has continued to increase since last decade of XX century but despite of the knowledge and experience acquired there are still problems encountered in practice. Well justified term "good weldability" refers exclusively to the group of technological features for easy metal parts joining by welding, but not to the automatic provision of corrosion resistance of welding joints, which in chlorides environment reaches only 50÷80% of original parent material resistance. Welding technology factors and impact on final corrosion resistance of welds are widely discussed. This includes particularly weld chemical composition, heat input balance, oxidation, nitrogen content, shielding and purging gas, and the practical constraints of the welding process.
PL
Praca dotyczy natryskiwanej plazmowo powłoki NiCrFeSi na podłoże ze stali kotłowej (P 250GH). Powłokę obciążano cieplnie w atmosferze powietrza i w środowisku siarki. Obciążenie cieplne wynosiło 2000 cykli. Jeden cykl obejmował: nagrzewanie do temperatury 560 °C i wygrzewanie w tej temperaturze w czasie 3 minut, chłodzenie do temperatury 300 °C, nagrzewanie do 560 °C i wygrzewanie w tej temperaturze w czasie 1,5 minuty oraz chłodzenie do temperatury 150 °C. Efektem obciążeń cieplnych było zmniejszenie grubości powłoki o 39 μm. Stwierdzono, że siarka dyfundowała w warstwę przypowierzchniową. Tworzące się produkty jej reakcji z niklem i chromem sprzyjały wykruszaniu się składników tej warstwy, które następnie ulegały utlenianiu.
EN
The paper deals with a NiCrFeSi coating plasma-sprayed on a boiler steel (P 250GH) substrate. The coating was heat-loaded in atmosphere of air and in sulfur environment. The heat load comprised 2000 cycles, whereas each of the cycles included: heating up to 560 °C and soaking at the temperature for 3 minutes; cooling down to 300 °C and soaking at the temperature for 1.5 minutes; and cooling down to 150 °C. As a result of such thermal cycling, thickness of the coating was reduced by 39 μm. It has been found that sulfur had diffused into the superficial layer. The occurring products of sulfur reacting with chromium and nickel contributed to spalling of components of the layer which subsequently were subject to oxidation.
EN
AISI 316L–hydroxyapatite biomaterials were produced by the conventional powder metallurgy technology. In the case of materials such as these, proper and long-term functioning in the aggressive environment of body fluids is very important. Therefore, the purpose of this study was to determine the effect of hydroxyapatite content and sintering temperature on the properties including sintered density, open porosity, and in particular corrosion resistance of AISI 316L–hydroxyapatite biomaterials in Ringer’s solution. The measurement of sintered density and open porosity of studied materials was carried out by the water-displacement method. The corrosion behaviour was studied by open circuit potential measurement and potentiodynamic polarization method. It was stated that the properties of studied biomaterials are dependent on chemical composition of powders mixture and sintering temperature. The results showed that higher sintering temperature ensured to obtain lower values of corrosion current density and corrosion rate, and higher value of polarization resistance. The addition of 5 wt % hydroxyapatite provided to a significant improvement of corrosion resistance in Ringer’s solution in comparison to AISI 316L steel, while a slight decrease in corrosion resistance was observed for AISI 316L–10 wt % hydroxyapatite biomaterials. Passivation ability and better corrosion resistance indicate that sintered at 1240°C AISI 316L–5 wt % hydrohyapatite biomaterials is more appropriate for long-term functioning implants than AISI 316L steel. This biomaterial possessed good densification and the best corrosion resistance among all studied materials, as evidenced by the lowest corrosion current density and corrosion rate combined with the highest polarization resistance.
PL
W przypadku biomateriałów właściwe i długotrwałe funkcjonowanie w agresywnym środowisku płynów ustrojowych jest bardzo ważne. Austenityczne stale nierdzewne przy dobrych właściwościach mechanicznych wykazują jednak znaczną podatność na korozję elektrochemiczną, natomiast hydroksyapatyt charakteryzuje się bardzo dobrą biozgodnością i odpornością na korozję. Wprowadzenie dodatku hydroksyapatytu może wpłynąć na poprawę odporności korozyjnej, biozgodności, ale także właściwości tribologicznych stali AISI 316L. W pracy dokonano oceny odporności na korozję w roztworze Ringera spiekanych biomateriałów AISI 316L– hydroksyapatyt. Ponadto określono gęstość i porowatość otwartą otrzymanych materiałów. Na podstawie przeprowadzonych badań potencjodynamicznych i wyznaczonych parametrów korozyjnych określono wpływ zawartości hydroksyapatytu i temperatury spiekania na odporność na korozję badanych materiałów.
18
EN
Purpose: This paper is devoted to the investigation of gaseous hydrogen and ash gas turbine fuel influence on the mass loss in long-term corrosion and mechanical properties of cast heat-resistant blade materials. It has been established that the level of corrosion resistance of the investigated alloys (Ni59Cr21Co10W4Ti3Al3MoLa (SM-104-VI); Ni57Cr16Co12W6Ti4Al3Mo2Hf (SM-90-VI); Ni57Cr16Co11W6Ti4Al4Mo2Hf (SM-88U-VI)) correlated with the chromium content and is the highest among similar materials. The advantage of SM-104-VI alloy increases with the increasing of time base and temperature. Design/methodology/approach: This work presents research results concerning corrosion and hydrogen resistance of a investigated alloys examined at a standart mechanical tests under short-term static tension was determined on smooth cylindrical five-time samples with a diameter of the working part 5 mm at speed 1 mm/min. The destructed areas were examined by optical and electron microscopes with computer image analysis. Findings: It has been found that the level of resistance of the investigated alloys high- temperature sulfide and oxide corrosion in the ash of the gas turbine fuel is correlated with the criterion alloying and is the highest among the known materials of the blades. The value of specific mass loss decreases in the order of SM-88U-VI, SM-90-VI, SM-104-VI. Moreover, its advantage over alloys of SM-90-VI and SM-88U-VI as bigger as the time the corrosive environment. Research limitations/implications: An essential problem is the verification of the results obtained using the standart mechanical tests, computer-based image analysis and other methods. Practical implications: The observed phenomena can be regarded as the basic explanation of reduces the plasticity characteristics of the alloys for gas turbine blades. Originality/value: The value of this work is that increasing temperature reduces the negative influence of hydrogen, however, even at 900°C, the values of elongation and transverse contraction in hydrogen is lower than in the air. For a short stretch in the temperature interval 20-900°C the least sensitive to the action of hydrogen at a pressure of 30 MPa is a single crystal SM-90-VI alloy.
EN
The paper discusses the possibility of improving resistance of heat exchangers made of gray cast iron with flake graphite to high-temperature corrosion by providing them with metallic coatings. A metallic coating containing 76.9% Ni, 19.8% Cr, 1.7% Si, 0.9% Fe, and 0.9% Mn was applied by means of the plasma spraying method and subjected to cyclically variable thermal loads in the atmosphere of solid fuels combustion products (oxygen, sulfur, chlorine, and sodium). In a 30-day thermal load test held at temperature 500°C it has been found that thickness of the metallic coating decreased from the initial (240 ± 6) μm to (231 ± 6) μm. The depth to which sulfur, chlorine, and sodium penetrated the coating was about 30 μm. Increased oxygen content occurred along the whole coating depth. In the coating area adjacent to the substrate surface, the content was twice as high compared to this observed in the initial coating material. Although presence of oxygen was found within the whole depth of the coating, i.e. (231 ± 6) μm, no signs of susceptibility of the sprayed metallic layer to separation from substrate of gray cast iron with flake graphite were found.
EN
Magnesium-based materials have promising mechanical properties and potential to serve as implants for loadbearing temporary applications. The main concern about such implants is their strength and resistance for the acting forces. In this investigation, magnesium-based biodegradable Mg65Zn30Ca4Gd1 alloy prepared by combination of innovative Mechanical Alloying (MA) and Spark Plasma Sintering (SPS) methods, was studied for the structure and mechanical properties. Structural studies were performed using X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). XRD studies were conducted to gain an overview of the phase composition in powdered and sintered samples. The energy dispersive spectroscopy (EDS) additionally determine the chemical composition of the samples. SEM observations were used to examine the morphology of the sinters on the fractured surface after the compressive tests. Mechanical properties of the Mg65Zn30Ca4Gd1 alloy were examined by compressive tests, to determine the compressive strength and Young's modulus of the samples at room temperature. The paper provides information about the density and porosity of the Mg-based alloy and additionally its corrosion resistance. Moreover the work shows advantages and possibilities of forming multi-compound, morphologically homogeneous alloys with high mechanical properties in the powder metallurgy processes.
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