rss_2.0Koroze a ochrana materialu FeedSciendo RSS Feed for Koroze a ochrana materialu a ochrana materialu 's Cover of the welded joint of austenitic steel NEUTRONIT A 976 SM in the corrosive environment of boric acid<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with the influence of the operating environment on the safe resistance of the welded joint of the construction material used in the nuclear power industry in the production of spent nuclear fuel containers. This material contains a higher percentage of alloying boron and is used as a shielding construction material for neutron and gamma radiation. It is used to produce baskets for spent nuclear fuel containers. When the containers are being filled, the welded joint of the basket structure are briefly exposed to an aqueous boric acid solution. The aim of this work was to determine the effects of exposure to the corrosive boric acid environment on the mechanical properties of the material. Tensile tests on the original weld and post weld exposure in H<sub>3</sub>BO<sub>3</sub> and corrosion cracking tests on unexposed welds were performed. The evaluation of the results revealed that the exposure to the corrosive environment of boric acid did not significantly affect the strength characteristics of the tested material NEUTRONIT A 976 SM.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Dissimilar weld joint corrosion in simulated boiler water environment<abstract> <title style='display:none'>Abstract</title> <p>This paper is focused on the problematics of weld joint corrosive degradation in the boiler water environment. The boiler water is commonly used in power industry. The corrosion experiment simulated the boiler water environment during shutdown, when chemicals may be concentrated in the deposits, or as a result of evaporation. The corrosion experiment was performed on heterogeneous weldments made of P265GH//X6CrNiTi18-9 steels in the environment of stagnant boiler water with the addition of NaCl for 53 days. The data showed only minimal weight losses, and small changes in the measured fracture toughness of the welded joint. At the same time, a tendency for a mechanical weakening of the welded joint with the increasing aggressivity of the boiler water environment was observed. The metallographic analysis was performed to describe the nature of corrosive degradation.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Prediction models for the kinetics of iron boride layers on AISI 316L steel<abstract> <title style='display:none'>Abstract</title> <p>The boronizing kinetics of AISI 316L steel has been analyzed by employing five prediction models. The boron diffusion coefficients as well as the growth rate constants in the FeB and Fe<sub>2</sub>B phases were firstly evaluated in the range of 1123-1223 K. Afterwards, the values of boron activation energies in FeB and Fe<sub>2</sub>B were secondly deduced by adopting the Arrhenius relationships.In addition, the prediction models have been validated experimentally for two boronizing conditions (1170 K for 1.6 h and 1210 K for 1.1 h). The predicted results were deemed very concordant with the experiments. Furthermore, advantages and limitations about the applicability of these models were also discussed.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Innovative accident tolerant nuclear fuel materials will help extending the life of light water reactors<abstract> <title style='display:none'>Abstract</title> <p>Nuclear power is a significant source of clean energy that can be used to mitigate climate change. In the western world, the average life of light-water power-reactors is increasing because no new reactors are being connected to the grid. In order to extend the life of the existing reactors innovative materials are being considered for the fuel of the reactors. The newer materials would be more resistant to a loss of coolant accident and allow for longer times between refueling plus permitting overall extended burn-ups, which will make the reactors safer and more economical to operate. This never used before in reactor materials include cladding concepts such as: 1) coated zirconium alloys, 2) monolithic iron-chromium-aluminum alloys, and 3) silicon carbide composites.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Growth kinetics of diiron boride (FeB) layer on a carbon steel by four approaches<abstract> <title style='display:none'>Abstract</title> <p>The pack-boriding kinetics of SAE 1020 steel has been addressed through utilizing four mathematical approaches in case of the formation of diiron boride layers. The values of boron diffusivities and activation energies in Fe<sub>2</sub>B were assessed in the interval of 1123 to 1223 K by using four models. Finally, the four models were experimentally verified by comparing the predicted results to the experimental value of Fe<sub>2</sub>B layer thickness determined at 1198 K for 6 hours. Finally, the simulated layers’ thicknesses agreed with the experimental result. In addition, similarities and differences observed in the models were also discussed.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Impact of the diffusion coefficient calculation on predicting FeB boride layer thickness<abstract> <title style='display:none'>Abstract</title> <p>In this study, a single-phase boride layer thickness Fe<sub>2</sub>B is predicted on two different substrates (Armco iron and XC38 steel) by following the integral method. This method is a mathematical model based on a system of differential algebraic equations that help to deduce the diffusion coefficient, which is the key factor on predicting the layer thickness. Literatures cover different diffusion coefficients for each substrate, albeit researchers usually extract from experimental data, variations of growth rate constants within only one time treatment and deduce the diffusion coefficient from them. This deduction is done via an estimation of a frequency factor and an activation energy from the growth rate constants. Therefore, our main aim is to illustrate the impact of the deduction of the diffusion coefficient on predicting the boride layer thickness. Lastly, the impact with and without incubation time on the boriding kinetics of both substrates was also examined.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Experimental studies on the corrosion inhibition of mild steel by 1-(phenylamino-1,3,4-thiadiazol-5-yl)-3-phenyl-3-oxopropan complemented with DFT Modeling<abstract> <title style='display:none'>Abstract</title> <p>1-(Phenylamino-1,3,4-thiadiazol-5-yl)-3-phenyl-3-oxopropan (PTPO) was selected as the investigated material for studying the protection performance for mild steel in 1 mol L-1 hydrochloric acid solution. The inhibitor was assessed using weight loss measurements complemented with morphological analytical techniques and density functional theory (DFT) modelling. The PTPO demonstrated significant inhibitive efficacy of 95.4% in the presence of 500 ppm at 303 K. The protection efficiency increases with the concentration increasing from 100 to 500 ppm, and no significant effect after 500 ppm. Furthermore, gravimetric findings reveal that the protection efficiency at 500 ppm PTPO increases with immersion period and increasing temperature (303-333 K), due to the effective adsorption of PTPO on the mild steel surface, and the protection efficiency value is 95.8% at 48 h of exposure and 95.4%, 95.4%, 95.7% and 95.9% at 303, 313, 323 and 333 K, respectively. The adsorption of PTPO on the mild steel surface obeyed the Langmuir adsorption isotherm model and revealing the mode of chemisorption adsorption. According to the DFT calculations, protection by PTPO is essentially performed by the heteroatoms in the inhibitor molecules which represented the adsorption sites, and the aromatic rings increase the electrostatic interaction between the PTPO molecules and the mild steel surface. The surface morphological studies, weight loss measurements, and DFT computational studies are in good agreement and that the selected corrosion inhibitor is adsorbed on the mild steel surface to form a protected layer on the surface of mild steel against the hydrochloric acid solution.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Corrosion assessment of a bronze equestrian statue exposed to urban environment<abstract> <title style='display:none'>Abstract</title> <p>This paper presents the characterization of the conservation state of a bronze equestrian statue exposed outdoor, through an in-situ, multi-analytical, and non-invasive approach. The artefact under study is a bronze equestrian statue, devoted to Alfonso La Marmora, placed in an urban environment in the city of Turin. The investigation was carried out in the framework of a restoration intervention, with the principal aim of characterizing the overall conservation state of the sculpture to provide the conservators with information useful to develop a tailored restoration plan. X-ray fluorescence spectroscopy (XRF) was carried out for the identification of the elements present in the artefact alloy, showing that the statue was made using mainly two bronze alloys. Electrochemical Impedance Spectroscopy (EIS) was performed to study the corrosion mechanisms and to define the protective effectiveness of the patina present on the surfaces. Eventually, Raman spectroscopy (RS) was performed to characterize the chemistry and microstructure of the corrosion products, mainly identified as sulphates. The combination of these techniques allowed to confirm the presence of wax layers from previous restoration work, still capable to protect the metal substrate against corrosion. In addition, it was possible to correlate the conservation state to the exposure conditions and location on the statue.</p> </abstract>ARTICLE2022-04-18T00:00:00.000+00:00Protective ability of lead corrosion products in indoor atmosphere with acetic acid vapours<abstract> <title style='display:none'>Abstract</title> <p>Lead corrosion products can undergo certain changes over the time in terms of composition. How these changes affect the corrosion of the underlying lead is an important question for protection of historical lead artefacts. In this work, we focus on characterization of changes in composition of lead corrosion products and how the composition affects corrosion of the lead substrate. Prepared model corrosion products on lead coupons were exposed to air at different relative humidity and concertation of acetic acid vapours. Composition of the corrosion products was analysed by XRD and corrosion rate was calculated from gravimetric data. Measurement of polarization resistance was implemented to get more insight into the protective ability of formate corrosion products. With lead formate covering the surface, the corrosion rate of lead coupons was minimal even in humid air with 400 ppb of acetic acid vapours. Acetic acid was however able to alter lead carbonate corrosion products resulting in increased corrosion rate.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Indoor corrosivity classification based on lead coupons<abstract> <title style='display:none'>Abstract</title> <p>Air pollution in museums, libraries, churches, and other indoor environments of cultural heritage objects was studied since 1980s. For classification of corrosivity for such type of indoor environments the ISO 11844 series was developed in 2006. In 2020 the revision of this ISO 11844 series had been finished, where lead was included as standard specimen with high sensitivity to vapour organic acids. This paper gives results of exposure of lead standard coupons in museums and other similar indoor environments together with measurement of climatic parameters and air pollution to verify the new approach.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Inspection possibilities of metallic material surface integrity by conventional ultrasonic technique<abstract xml:lang="en"><title style='display:none'>Abstract</title><p> The article is focused on the possibilities of ultrasound surfaces control on metallic materials by conventional ultrasonic techniques. Physical principles, types of ultrasonic waves to be used for surface control are described in the theoretical part. Three surface control techniques are listed in the experimental part of article. The first technique is a common control by angle ultrasonic probe with using transverse waves. The second technique is surface control by 30-70-70 creep waves and third techniques is surface testing by Rayleigh waves. Practical examples of ultrasonic testing for all techniques are illustrated. The conclusion of the article is devoted to the advantages and limitations of the individual testing methods.</p></abstract>ARTICLE2017-07-22T00:00:00.000+00:00The influence of deformation on the corrosion properties of the material<abstract xml:lang="en"><title style='display:none'>Abstract</title><p> This work was focused on changes of corrosion behaviour influence of deformation. The This work focuses on changes in corrosion behaviour under the influence of deformation. The main purpose is to observe the changes caused by tensile stress. The experimental material used is steel 1.4301 and titanium GRADE 2. The measurements were carried out using a potentiostat, which measures potential changes over time and electric current. The electrolyte used was 3.5% NaCl. Corrosion properties, especially polarization resistance, corrosion potential and corrosion rate, were evaluated from the measurements. The results demonstrate the changing corrosion properties depending on deformation. The corrosion properties worsened as the deformation increased.</p></abstract>ARTICLE2017-07-22T00:00:00.000+00:00Copper and copper patina<abstract xml:lang="en"><title style='display:none'>Abstract</title><p> This article is aimed at summarizing knowledge about copper and patina that is formed on the surface of copper. The article describes chemical processes in patina formation and explains the difference between natural and artificial patina, as well as some methods used in the investigation of patina such as XRD analysis, EIS analysis, Raman spectroscopy</p></abstract>ARTICLE2017-07-22T00:00:00.000+00:00The tribological properties of Al-brasses in various environments<abstract xml:lang="en"><title style='display:none'>Abstract</title><p> Tribological properties of Al-brass pipes of various producers were studied in different environments. The tested brasses have very similar chemical composition, but they differ in microstructure due to mainly by heat treatment after cold drawing. Microstructure as well as roughness of surface influence chemical and mechanical properties which are important in operating conditions. The experiments of tribological behavior were made in various environments, dry air, cooling treated water and 3.5 % solution of NaCl at room temperature 21 ± 2°C. The tribological tests were carried out on the Linear Tribometer at normal loading 5 N by the method ball on plate for the duration of 5500 s. The measured friction coefficients were evaluated by the program DIAdem and the diagrams were created from signal generated by software NSignal Express</p></abstract>ARTICLE2017-07-22T00:00:00.000+00:00Corrosion problems and solutions in oil, gas, refining and petrochemical industry<abstract xml:lang="en"><title style='display:none'>Abstract</title><p> The aim of this work is to describe and analyze corrosion problems and their solutions in oil, gas, and refining industry. Corrosion phenomena and factors influencing them are discussed. Corrosion control and monitoring methods are illustrated. Corrosion management plays vital role in the solving of corrosion problems. The results are summarized in new book of the author “Corrosion Problems and Solutions in Oil Refining and Petrochemical Industry” published by Springer in 2016.</p></abstract>ARTICLE2017-07-22T00:00:00.000+00:00Anchorage length of patented wire cables in prestressed bridge girders<abstract> <title style='display:none'>Abstract</title> <p>This paper briefly describes the methodology, performance and the obtained results of unique experiments performed on original I-73 precast bridge girders. The main objective of the experiments was to determine the actual anchorage length of corroded-through fully grouted prestressing reinforcement (prestressing wires), which is important for determination of the residual load-bearing capacity of prestressed structures. Observation probes leading all the way to the prestressing wires were drilled on selected sections of the girders along the length of the prestressing reinforcement. Optical image acquisition devices were then installed at these probes. Subsequently, controlled breakage of the patented wires (corrosion failure simulation) and observation of the changes that occurred in the prestressing wires after relief of stress were carried out. Evaluation of the experiments was then performed by analyzing the images obtained before and after the prestressing reinforcement failure.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Monitoring of the atmospheric corrosivity by resistive sensors<abstract> <title style='display:none'>Abstract</title> <p>Atmospheric corrosivity is classified according to EN ISO 9223 Corrosion of metals and alloys – Corrosivity of atmospheres – Classification, determination and estimation. For the determination and estimation of the corrosivity category, standardized approaches are used. Monitoring of corrosivity with the application of various sensors is an actual trend. The paper gives results of verification of some types of sensors for this monitoring with standardized flat samples at atmospheric test sites in the Czech Republic. The trend of decreasing atmospheric corrosivity is evident in the last decade. Monitoring of the corrosion rate and mapping of the corrosivity become a very important step in preventing failures in long-term atmospheric exposition. This type of monitoring was used on bridge construction to estimate the seasonal effect of de-icing salts deposition, too.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Influence of conversion coatings on the resistance of adhesive joints to undercorrosion<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with the application of conversion coatings for the preparation of surfaces before adhesive bonding of galvanized and non-galvanized steels. The morphology of the coatings was monitored by electron microscopy. The corrosion characteristics of the conversion coatings were determined by linear polarization. Steels treated with conversion coatings were used to form bonded joints using three structural adhesives. The resistance of the joints to undercorrosion was determined following the change in the load-bearing capacity of the joints after exposure in the climatic chamber.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Mitigation of chloride induced corrosion in reinforced concrete structures and its modeling<abstract> <title style='display:none'>Abstract</title> <p>The paper is primarily focused on the description of transport of harmful species in concrete such as chlorides on one side and transport of corrosion inhibitors and nanoparticles used to diminish corrosion of steel reinforcement or seal the microstructure of concrete on the other side. The studied processes are helpful in reverting the chloride induced corrosion of the reinforcement in reinforced concrete structures. The transport mechanisms are summarized with the emphasis on their mathematical description and numerical solution. The paper shows modeling results of the processes including a comparison with experimental data on several typical examples. The efficiency of the methods is shown supported by experimental and numerical results. A good correlation of the models with experiments is achieved.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Corrosion in underground infrastructures<abstract> <title style='display:none'>Abstract</title> <p>There is a significant loss due to corrosion of buried infrastructure. Many pipes have failed due to mistreatment happening within them all around the world. Different soil aeration leads to macro corrosion cells that cause critical levels within the path corrosion leading to a loss of structural integrity of the buried pipes underground. This review paper seeks to address and presents a predetermined model developed by using software COMSOL Multiphysics to identify and characterize the areas experiencing a high rate of corrosion beneath the surface due to differential aeration. The pipe surfaces experience electrochemical reactions and reactant transport mechanisms in the soil and the pipes. Porosity and degree of saturation make the closed-form equations used to create the mass transport properties and electrical properties that constitute three-phase medium using standard soil parameters. The current model enables the study of soil property variations and conditions from the external environment pipeline corrosion. The model results conclude and agree well with the literature and case studies done at pipeline failure sites. The model used in this review will then enable water utilities to develop forecasting tools that may be useful for assessment.</p> </abstract>ARTICLE2021-10-05T00:00:00.000+00:00en-us-1