Characterization Of Corrosion Products Research Articles

Effect of Al/Ni Ratio on the Microstructure and Properties of Nickel-Aluminum Bronze Alloys.

To study the effect of aluminum and nickel elements on the microstructures and properties of the nickel-aluminum bronze (NAB) alloy, four kinds of alloys with different compositions, ZCuAl7-7-4-2, ZCuAl8-6-4-2, ZCuAl9-5-4-2, and ZCuAl10-4-4-2, are prepared by vacuum-melting technology. The effects of different Al/Ni ratios on the microstructures of NAB are investigated using a metalloscope, scanning electron microscopy, transmission electron microscopy, and XPS analysis. The mechanical property is evaluated with microhardness testing and tensile mechanical testing. The corrosion resistance is evaluated using mass-loss testing, electrochemical testing, and corrosion-product characterization. The results show that with the increase of the Al/Ni ratio, the content of precipitated phases increases, while β' and hard κ, which have a different morphology, appear. As the Al/Ni ratio rises from 1 to 2.5, the hardness increases from 104 HV to 202 HV, and the tensile strength increases by 394 MPa from 356 MPa to 751 MPa, but the elongation decreases substantially from 50.50% to 11.00%. The best corrosion resistance is shown on ZCuAl7-7-4-2, with a corrosion rate of 0.00267 mm/a after 30 d of static immersion corrosion in 3.5 wt.% NaCl solution. Through electrochemical testing and corrosion-product characterization, it is found that ZCuAl7-7-4-2 has the largest polarization resistance Rp, and the selective corrosion of the surface is mild.

Characterization of corrosion products on contemporary bronze artwork by using voltammetry of microparticles and PCA

Voltammetry of Microparticles (VMP) is a solid-state electrochemical technique that has proven to be helpful in the examination of cultural heritage metallic objects. Herein, VMP procedure was firstly applied to the electrochemical characterization of standard bronze corrosion products, such as tenorite (CuO), cuprite (Cu2O) and gerhardtite (Cu2(NO3)(OH)3), among others. Once a library of electrochemical fingerprints had been created, the procedure was applied to the characterization of surface materials of the Warrior with Shield by Henry Moore. Principal component analysis was used in order to discriminate between different species displaying more or less similar electrochemical responses. Peak potential and peak current values from square-wave voltammetric scans were used together with other parameters (i.e. peak width, half-peak potential, onset potentials), including Tafel slopes and ordinates at the origin. The electrochemical measurements were compared to FT-IR and SEMS-EDS analyses.

Research on the evolution of corrosion products of 17-4 PH martensitic stainless steel in the tropical marine environment

Deterioration of stainless steel is significantly influenced by the characteristics of corrosion products. Evolution of corrosion products of 17-4 PH martensitic stainless steel (17-4 PH MSS) in the tropical marine environment was systematically studied by field-exposure, combined with morphological observation, compositional characterization and electrochemical testing in this work. The corrosion process of 17-4 PH MSS was divided into three stages: stage I–rapid formation and shedding of corrosion products, stage II–adhesion and transformation of corrosion products and stage Ⅲ–remarkable increase in the protective properties of corrosion products. Corrosion rate of 17-4 PH MSS was maximum in the first stage and then decreased continuously in the second and third stages, which is closely related to the morphology, distribution and composition of the corrosion products. In terms of morphological evolution, corrosion products of 17-4 PH MSS showed the dynamic cycle characteristic of "nucleation-growth-cracking-shedding". In view of compositional transformation, the high content of Cr, Ni, and Cu in stainless steel is involved in the formation of corrosion products, and the production of Cr2O3, Cr(OH)3, FeCr2O4, NiFe2O4, and CuFeO2 after 6 months of exposure was an important shift. Argument from protective properties, increase in coverage percentage and the generation of Cr-containing products are responsible for the enhancement of protective properties of the corrosion products. This work prepares the way for further research on the generation and growth mechanism of pitting under corrosion products and provides technical support for the design, selection, and protection of stainless steel in tropical marine environments.

The corrosion mechanism of lead-glazed pottery in Han dynasty

Ancient pottery, having endured prolonged burial in soil, invariably underwent the process of glaze corrosion. The micromorphology and structural composition of four lead-glazed pottery fragments dating back to the Han Dynasty, excavated in the Qinhan New Town within Xixian New area of Xi’an are elucidated by comprehensive analysis method. The results reveal that the corrosion products predominantly comprised PbCO3, Pb3(PO4)2, CaCO3, and Ca3(PO4)2. Concurrently, the presence of organic substances exhibiting characteristic self-excitation fluorescence in the cracks of the sample is identified through fluorescence microscopy and Fourier infrared spectroscopy. Through a comparative analysis of well-preserved and severely corroded samples, taking into account compositional analysis, observations of corrosion morphology, and the characteristics of corrosion products, it is deduced that the primary corrosion mechanisms involve chemical corrosion, microbial corrosion, and crack corrosion. This study provides a comprehensive depiction of glaze corrosion process inherent to lead-glazed pottery and establishes corresponding corrosion models.

Characterization of corrosion products formed on Q235 carbon steel and T2 copper in the Antarctic atmosphere

This study delves into the intricate corrosion behavior of ferrous and non-ferrous alloys in the challenging Antarctic marine atmosphere. Despite the harsh conditions and exceptionally low anthropogenic emissions in Antarctica, materials are still susceptible to severe corrosion. The investigation focuses on two materials: Q235 carbon steel and T2 copper. Both display distinct corrosion cases between their skyward and groundward sides due to the abrasive impact of persistent strong winds carrying ice particles and grit. Electrochemical reactions at the anode and cathode drive surface corrosion processes, involving Cl− and SO42−, ultimately leading to the formation of various corrosion products. The study highlights the role of sulfur-containing aerosols, Methanesulfonic acid (MSA) and non-sea-salt sulfate (nss-SO42-) in corrosion processes, as well as the interaction between Cl− and copper in forming corrosion products. The findings emphasize the complex interplay of environmental factors like wind, ice cover, and aerosols with materials, leading to diverse corrosion products and surface transformations. Further research is crucial to gain a comprehensive understanding of corrosion challenges in extreme environments like Antarctica and to develop effective mitigation strategies.

Failure analysis of the end surface of the burner nozzle made of UMCo50 material in long-term high temperature oxygen-enriched sulfur-chlorine environment

As the core device of coal water slurry gasification technology, the failure of the burner nozzle will bring serious technical and safety problems. The purpose of this paper is to determine the mechanism of burner failure based on the characteristics of corrosion products and cracks. The results showed that the Cr2O3 oxide film on the surface of UMCo50 was damaged under the effect of mechanical erosion, high temperature and stress, and the corrosive elements S and Cl in the combustion chamber made it further cracked and peeled off. Therefore, the matrix was corroded and cracks occurred. During the crack propagation process, more M23C6 carbides were precipitated at the grain boundary, it caused Cr-depleted at the grain boundary, which reduced the corrosion resistance of the matrix near the grain boundary. The exfoliation of carbides distributed along the grain boundary also accelerated crack propagation. Through XPS and XRD analysis, it was found that the main corrosion products on the crack surface of the failed parts were: Cr2O3, CoCr2O4, CoO, Fe2O3, FeS. According to the causes of failure analysis, the corresponding improvement measures are put forward.

Characterization and Corrosion Behavior of Zinc Coatings for Two Anti-Corrosive Protections: A Detailed Study

The purpose of this research is to characterize and evaluate the corrosion behavior of zinc coatings used for corrosion protection, with a special focus on the S235 steel material. The introduction highlights the need for corrosion protection in industrial settings, as well as the importance of understanding corrosion processes and the development of corrosion products to develop more effective solutions. The study’s goals are to undertake an extensive analysis of corrosion products formed on the zinc coating’s surface, to evaluate the performance of these coatings under atmospheric circumstances, and to investigate the effect of deposition parameters on coating quality. The essential message provided to readers is the critical significance of knowing corrosion product formation mechanisms and zinc coating corrosion behavior in developing long-lasting and effective protection measures. The study methodology includes cycle testing, morphological and chemical examination of corrosion products, as well as optical and electron microscopy and energy-dispersive spectroscopy. Corrosion resistance is assessed using accurate measurements. The results show that zinc coatings have exceptional corrosion resistance under air settings, with the produced corrosion products offering further protection to the underlying material. Furthermore, the study demonstrates that the surface roughness of S235 steel has a substantial impact on the quality and corrosion behavior of hot-dip galvanized coatings. The findings emphasize the necessity of detailed characterization of corrosion products, the effect of depositional factors on zinc coating performance, and the need for novel corrosion protection methods. These discoveries have significant implications for the corrosion protection sector, providing the potential to improve the longevity and efficiency of protective systems used in industrial applications.

Probing pipe flow impact corrosion monitoring effectiveness under corrosion monitor coupons conditions

To reduce the corrosion failure frequency of oil and gas pipelines, corrosion monitoring coupons are often used to evaluate the internal corrosion status of pipelines. However, the local flow field varies after the installation of the coupons, so the monitoring corrosion rate is different from that of the pipe wall. To evaluate the effectiveness of corrosion coupons monitoring, a lab-scale flow loop system was used to carry out flow corrosion experiments to obtain the local corrosion rates of corrosion monitoring coupons and pipe wall, respectively. Combined with the characterization of corrosion products and multiphase flow, a mechanism model of corrosion monitoring effectiveness was established. It was clear that the deviation of corrosion monitoring rate was related to the flow rate, shear force and turbulent kinetic energy. The accumulation of corrosion media and the detachment of corrosion product films resulted in variation in the morphology and the monitoring effectiveness.

Rapid Quenching of Molten Salts as an Approach for the Coordination Characterization of Corrosion Products

A new apparatus was built to rapidly cool molten salts in liquid argon to prevent contamination during quenching and enable new insight into the structure in the liquid state. To test the applicability of the apparatus, several industrially relevant chloride salt compositions were first melted, rapidly solidified, and then characterized. The design proved applicable for the rapid quenching of molten salt. Furthermore, the structure of the apparatus prevented exposure of the rapidly quenched salt to impurities (humidity, oxygen, etc.). X-ray diffraction of salt specimens cooled with and without liquid argon showed differences including a structure further from the expected stoichiometric equilibrium with rapid cooling. Of particular interest is the chemical state of metallic impurities, and this may be probed using electron paramagnetic resonance.

Characterization of corrosion products formed on tin-bronze after 29 years of exposure to Shenyang, China

Characterization of corrosion products formed on tin-bronze exposed to industry atmosphere for a 29-year period was investigated. Results demonstrated that the corrosion rate of tin-bronze was 0.56 μm·a−1. Tin-bronze had two completely different structures on two exposure sides—the corrosion products layer on skyward side was uneven with cracks, and the corrosion product on the field-ward side is a double-layer structure with dense inner layer and porous outer layer. Sn is uniformly distributed in the corrosion products layer on skyward side, and densely concentrated near the substrate on field-ward side.

Pseudomonas xiamenensis in the cutting fluids on corrosion behavior of aluminum alloy 2219

Aluminum alloy workpieces are prone to black spots and other corrosion problems in the cutting process, which greatly puzzles the machining industry and brings serious losses. However, the cause and mechanism of workpiece corrosion are still unclear. In this study, the effect of P. xiamenensis breeding in the cutting fluid on the corrosion of aluminum alloy 2219 (AA 2219) was studied by corrosion product characterization, biofilm evaluation, corrosion profile, quantitative pit analysis, and electrochemical characterization. The results showed that P. xiamenensis adhered to the surface of AA 2219, forming uneven corrosion product film and biofilm. The state of the film on the surface of the aluminum alloy changed, and pitting corrosion intensified after being immersed in cutting fluid containing P. xiamenensis. The maximum corrosion depths of the coupons were found to be 2.7 μm and 15.8 μm in sterile and inoculated cutting fluids, respectively. The corrosion rate of the aluminum alloy was as high as 9.16 × 10-3 mm/y, which was about 9 times higher than the corrosion rate in the microbial-free cutting fluid. The presence of a P. xiamenensis biofilm accelerated the formation of the water-soluble corrosion product Al(OH)4-, which destroyed the passive film and accelerated pitting corrosion.

Investigation of carbon steel corrosion by oilfield nitrate- and sulfate-reducing prokaryotes consortia in a hypersaline environment.

Microbiologically influenced corrosion (MIC) behavior of the AISI 1020 carbon steel caused by consortia of nitrate-reducing prokaryotes (NRP) and sulfate-reducing prokaryotes (SRP) was investigated separately in hypersaline seawater conditions. Microbiological analysis, surface images, characterization of corrosion products, weight loss, and electrochemical measurements were employed to monitor the corrosion process for 10days at 40°C. Compared to abiotic corrosion (control), the extent of corrosion was more aggravated in the conditions with microbial consortia. It corroborates the critical role of microbial activity in corrosion processes in natural and industrial environments since microorganisms are widely spread. Corrosion rates obtained from Tafel extrapolation were statically equal for both microbial consortia (0.093 ± 0.009mm.y-1); however, the maximum pit depth on the steel surface subjected to NRP-MIC was about 25% deeper (48.5µm) than that caused by SRP-MIC (32.6µm). In contrast, SRP activity almost doubled the number of pits on the steel surface (2.7 × 104 ± 4.1 × 103 pits.m-2), resulting in more weight loss than NRP activity. In addition, SRP cells formed nanowires to support direct electron uptake from steel oxidation. This research contributes to the understanding of steel corrosion mechanisms in hypersaline environments with the prevalence of NRP or SRP, as oil reservoirs undergo nitrate injection treatments.

Cover Picture: Materials and Corrosion. 8/2022

Cover:Differently pre‐patinated zinc surfaces were exposed in both laboratory and field setups. Measurements of zinc runoff and characterisation of corrosion products show that long‐term field exposures can be simulated in the laboratory using consecutive rain events.More detailed information can be found in: Gunilla Herting, Ville Saarimaa, Golrokh Heydari, Aaretti Kaleva, Per‐Erik Sundell, Inger Odnevall, Simulated rain exposures can mimic long‐term metal runoff at atmospheric conditions – a case study on naturally and pre‐patinated zinc sheet, Materials and Corrosion 2022, 73, 1178.

Mussel-inspired hydrophobic modification of boron nitride nanosheets to enhance the dispersion and anticorrosive performance in polymeric coatings

Boron nitride nanosheets (BNNSs), a two-dimensional (2D) insulator material with outstanding barrier properties, are prone to aggregation owing to π-π interaction, which limits their use in heavy anti-corrosive coatings. In this work, urushiol (Ur), a cheap and easily available natural compound, was employed to modify BNNSs via interacting catechol groups of Ur with the surface of BNNSs inspired by mussel, which was proved by UV–vis, Raman, FTIR, and XPS. Synthesized BNNSs@Ur exhibited high hydrophobicity and dispersibility in solvents and epoxy coatings (EP), which enhanced the compatibility between the BNNSs and matrix. Electrochemical impedance spectroscopy (EIS) clearly manifested that the impedance at low frequency (|Z|f = 0.01 Hz) of the polymeric coating containing 0.75 wt% BNNSs@Ur was about two orders of magnitude higher than that of pure EP coating immersed in 3.5 wt% NaCl solution for 50 days. Characterization of corrosion products also evidenced that the modified BNNSs significantly enhanced the anticorrosive resistance of EP coatings via the improved barrier performance and corrosion inhibition effect of Ur, which is supposed to be extensively used as nano-reinforcing fillers in the field of corrosion protection.

Raman spectroscopic characterization of corrosion products of archaeological iron

Abstract Raman spectroscopy is a versatile analytical technique which allows the detection of different molecules analysing the vibrational modes. As a matter of facts, the vibrational frequencies are typical of a specific chemical bond or of a structural symmetry. In this study, the Raman technique is used for the determination of iron corrosion products, mainly oxides and hydroxides. Metallic artefacts buried in soil are affected, in dependence of their electrochemical nobility, by corrosion phenomena of various entities, which partially modify their chemical composition and their structure. The process may occur both during burial time and after the extraction from the archaeological site, implying the potential loss of information about the metallurgical technology and structure of the object. The study of the corrosion phenomena allows to propose tailored strategies for the restoration and conservation of the artefacts, especially in view of the storage of the artefacts in a museum. This study validates the use of the Raman technique for this purpose, showing its efficiency in the identification of the iron corrosion products in favourable conditions for the analysis of Cultural Heritage artefacts, as the possibility of performing in situ analysis without the need of a previous sample preparation.

Anti-corrosion behaviors of corn-based polyols on low carbon steel rebar

The extensive application of chloride-based deicing chemicals has resulted in significant corrosion-induced deterioration in transportation infrastructure and vehicles. The objective of this research was to investigate corrosion inhibition performance of two low-cost, environmentally safe, and non-toxic corn-derived polyols – sorbitol and mannitol – on ASTM A615 low carbon steel rebar. The polyols were each added to a traditional pavement deicer (23.0% sodium chloride by weight) at 1.0%, 2.5%, and 5% by weight replacements. The steel samples were exposed to a continuous flow of solution during an electrochemical experiment by both linear polarization resistance (LPR) and potentiodynamic polarization (PDP). In addition, solution analysis was performed using inductively coupled plasma-mass spectrometry (ICP-MS), and corrosion product characterization was examined by scanning electron microscopy. The results demonstrated that the incorporation of corn-derived polyols in the deicing solution reduced the corrosion initiation and that the degree of inhibition increased as the weight concentration increased from 0% to 5%. Following the Langmuir adsorption isotherms, it is posited that the inhibitors reduced the corrosion rate via adsorption onto the steel surface and allowed for a passive layer to form, which was supported by additional surface analysis. Thus, the outcome from this study will contribute to the search for a sustainable approach to mitigating the environmental impacts of chlorides and steel corrosion.

Simulated rain exposures can mimic long‐term metal runoff at atmospheric conditions—A case study on naturally and prepatinated zinc sheet

AbstractShort‐ and long‐term zinc runoff are studied at field and laboratory conditions to show that a laboratory setup can simulate field conditions and to investigate how prepatination influences the zinc runoff process. Results from four differently patinated zinc surfaces exposed at laboratory conditions, seven consecutive individual 4‐h rain events, and exposure at field conditions for 2 years show that the laboratory setup does simulate field conditions provided that the limitations of the laboratory are considered. It is also determined through corrosion product characterization that denser established corrosion products (patina) have a lower runoff than bulky porous or newly formed corrosion products.

A new ternary composite steel rebar coating for enhanced corrosion resistance in chloride environment

This work reports a novel ternary cement polymer composite coating (CPFNIC) consisting of fly ash, nanoparticles, and inhibitor with enhanced corrosion protection for steel rebars in a chloride environment. Electrochemical impedance spectroscopy (EIS) measurements, polarization curves, salt spray test, scanning electron microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM) were used to understand the corrosion protection mechanism and for characterization of corrosion products. The results show that the new coating significantly delayed the onset of corrosion on rebars in aggressive chloride environments due to the synergistic contributions from the additives used. The electrochemical studies (open circuit potential and corrosion current) indicate a significantly improved corrosion performance of CPFNIC as compared to uncoated rebars. The potentiodynamic polarization results of CPFNIC coated rebars showed high corrosion potential, low corrosion current density, three order higher polarization resistance, and two-order lower corrosion rate than the uncoated rebar. The EIS measurements showed a significantly higher charge transfer resistance for the CPFNIC as compared to the uncoated rebar. The visual inspection and weight loss measurements in salt spray and chemical resistance tests of CPFNIC coated rebars corroborated its improved resistance in chloride environment. Our results suggest the benefits of ternary composite cementitious coating on rebars in enhancing the corrosion protection.

Characterization of Corrosion Products Formed on Beryllium-Bronze and Tin-Bronze after 29 Years of Exposure to a Typical Industrial Atmosphere

Characterization of Corrosion Products Formed on Beryllium-Bronze and Tin-Bronze after 29 Years of Exposure to a Typical Industrial Atmosphere

Evolution of corrosion products on ASTM A36 and AISI 304L steels formed in exposure to molten NaNO3–KNO3 eutectic salt: Electrochemical study

Thermal energy storage uses molten salt as a heat transfer fluid implies a high corrosion risk. In this work, ASTM A36 and AISI 304L steel, exposed to solar salt at 390 °C for 21 days, were studied by electrochemical impedance spectroscopy. The results were validated by mass gain and the characterization of corrosion products. Carbon steel revealed a porous behavior related to the formation of corrosion products based on iron oxides, as described the De Levie´s theory, whereas stainless steel showed the formation of a passive multilayer of iron and chromium oxides, which was adjusted to the Power-law model.