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In this study, Al 2 O 3 –20TiO 2 (AT) and Cr 2 O 3 –3TiO 2 –5SiO 2 (CT) coatings were prepared by atmospheric plasma spraying (APS), The microstructure, phase compositions and corrosion behavior were studied comparatively. The results indicated that both coatings had layered structure, with an average surface roughness RA around 6 μm, an adhesive strength around 35 MPa, and a porosity around 4 %. The AT coating mainly composed of γ-Al 2 O 3 and α-Al 2 O 3 , and the CT coating composed Cr 2 O 3 respectively. Moreover, the AT coating exhibited better corrosion resistance than the CT coating. In artificial seawater, the corrosion process was strongly related to the porosity. The corrosion rate (based on the corrosion current density) of the two coatings showed a same trend which decreased first and then increased. It was thought that the blocking of early corrosion products in holes was helpful to delaying the progress of corrosion. In contrast, the later corrosion products would promote the formation and propagation of cracks, accelerating the corrosion. In the simulated environment with high pressure and hydrogen sulfide seawater, the corrosion process was strongly related to the porosity as well as the brittleness of the coatings. The corrosion rate (based on the weight loss) of the AT coatings still remained the same trend as it in the artificial seawater. However, the CT coating showed a continuously increasing corrosion rate, due to higher porosity and brittleness resulted in a large number of cracks under external stress, which offered corrosion channels. [ABSTRACT FROM AUTHOR]

• Gas-solid coupling corrosion of steels under Cl-containing environment is studied. • The gas–solid coupling corrosion is much stronger than the independent gas corrosion. • Two layers of corrosion products with huge different characteristics are observed. • FeCl 2 &CrCl 2 amalgamate with the chloride salts form a low-melting liquid phase layer. • The O and Cl elements react with the metal substrate through the molten layer. The fast development of the waste incineration industry requires deeper insights into heating surface corrosion behavior at higher operating parameters with complex corrosion sources. This research investigates the corrosion behaviors of three types of plates, namely SA210-C, TP310, and 12CrMoV, when subjected to simulated flue gas and fly ash deposition simultaneously at temperatures ranging from 500℃ to 620℃. The results indicate that the weight loss due to coupling corrosion was 2.5 to 84.5 times higher than that of gas-phase corrosion under the same operating conditions. Among the three stainless-steels, TP310 demonstrates superior corrosion resistance. It is worth noting that, under the gas–solid coupling corrosion conditions, we observed a distinct two-layer structure of corrosion products. Despite the fly ash simulants detaching over time, the two-layer structure remained unchanged. Based on the theory of eutectic molten salt formation, we propose that alkali metal chlorides only initiate the formation of the molten layer in the initial stage of corrosion. Furthermore, we offer additional suggestions for the mechanism of sustaining the molten layer in the absence of alkali metal chlorides. [ABSTRACT FROM AUTHOR]

The effect of 10 wt% alumina, 20 wt% (10Al 2 O 3 -10MoS 2), and 30 wt% (10Al 2 O 3 -10MoS 2 -10Ag) reinforcements on the tribological and corrosion properties of copper was investigated. The nanocomposites were prepared by the ball milling coating method and then fabricated by the cold and hot compaction technique. The copper's hardness increased gradually from 96 HV to 227 HV for the 30 wt% (Al 2 O 3 -MoS 2 -Ag) representing an increase of 136.48 %. Adding 30 wt% (Al 2 O 3 -MoS 2 -Ag) to the copper reduced the wear rate from 22 mg/min to 0.3 mg/min under 50 N applied load, owing to the presence of two types of self-lubricating materials, MoS 2 and Ag. This nanocomposite recorded the lowest mean coefficient of friction of 0.166 compared with 0.23 for copper. Adding the alumina increased the copper corrosion rate to 3.83 mm/year due to increased oxidation ratio that facilitates the penetration of the electrolyte. However, the Cu/(Al 2 O 3 -MoS 2 -Ag) sample recorded corrosion rates of 0.467 mm/year compared with 0.446 mm/year for copper. [ABSTRACT FROM AUTHOR]

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This study investigated the effect of severe plastic deformation induced by friction stir back extrusion on microstructure, mechanical properties, and corrosion resistance of Al-Cu-Mg alloy containing 0.5 wt.% of lithium micro-alloy and Cu/Mg ratio of 3.8. The effect of the rotational speed of friction stir back extrusion in the range of 600-1200 rpm in the constant traverse speed of 20 mm/min was studied. The results show that the size of equiaxed grains formed during the friction stir back extrusion process due to dynamic recrystallization increases from 21.0 ± 2.3 to 29.6 ± 4.5 μm by enhancing rotational speed from 800 to 1200 rpm. The dominance of the temperature effect on the plastic strain on the surface of wires during the friction stir back extrusion process results in the formation of coarser grains at the surface of wires. Friction stir back extrusion by a rotational speed of 800 rpm and a traverse speed of 20 mm/min result in the maximum yield, tensile strength, and minimum corrosion rate of 353.56 ± 10.31, 509.91 ± 11.56 MPa, and 0.008 mm/year, respectively. The friction stir back extrusion process has increased at least 23, 39, and 29% in yield strength, ultimate tensile strength, and elongation compared to as-cast alloy. [ABSTRACT FROM AUTHOR]

The influence of pre-tensile deformation at different directions on the corrosion properties of AZ31 rolled sheet has been investigated. Uniaxial tensile test with the strain of 6% has been carried out at angles of 0°, 15°, 30°, 45°, 60°, 75° and 90° with rolling direction (RD), respectively. The corrosion behavior of specimens with different deformation directions in 3.5% NaCl solution and 8.5% Na2SO4 solution was measured by immersion test, potentiodynamic polarization method and electrochemical impedance spectroscopy. After immersion tests, the surface characteristics of various specimens were investigated by scanning electron microscope (SEM). Results showed that the tensile directions had a significant influence on the corrosion behavior. With the increase of the angle between tensile direction and RD, the hydrogen evolution rate in the 3.5% NaCl increased first and then decreased. The turning point was A45 specimen with the minimum value of 2.1 mm/y. The similar trends were also observed in the 8.5% Na2SO4 solution. In electrochemical testing, the A45 specimen exhibited the best corrosion resistance with the largest diameter of the impedance arc and lowest self-corrosion current. The further the angle of the specimen deviated from 45° direction, the lower corrosion resistance. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) has garnered significant attention in industries owing to its ability to produce complex geometrical components with lower production costs. In the present work, WAAM process was used to fabricate rectangular plates and cylindrical tubes from ER70S6 filler material based on the cold metal transfer technique. The microstructure of the rectangular plate was investigated at three different locations, viz., top, middle and bottom regions along the build direction (BD). It was characterized by the presence of ferrite and pearlite phases along with Mn and Fe rich carbide precipitates. The average grain size of the middle location was found to be marginally higher as compared to the other two locations which resulted into lower hardness in the former. The tensile properties were evaluated for three directions, i.e., 0°, 45° and 90° with respect to BD. The total elongation and strength were found to be slightly higher for the specimen deformed 90° with respect to BD. Furthermore, the performance of the additive manufactured components was analyzed through corrosion and compression tests. The corrosion current density and corrosion rate were found to be higher for the middle location as compared to the top and bottom locations owing to its higher pearlite fraction. The compression of tubes was carried out under axial and transverse loading conditions. Axisymmetric progressive folding of the tubes was observed under axial loading, whereas infinity shape formation was witnessed under transverse loading. The above deformation modes indicated the uniformity in mechanical properties of WAAM tubes without any discontinuity, and further suggested that these tubes could act as excellent energy absorbers. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are superior energy storage devices that are widely utilized in various fields, from electric cars to small portable electric devices. However, their susceptibility to thermal runaway necessitates improvements in battery case materials to improve their safety. This study used electrochemical analyses, including open-circuit potential (OCP), potentiodynamic polarization, and critical pitting temperature (CPT) analyses, to investigate the corrosion resistance of super duplex stainless steel (SAF 2507) applied to battery cases in relation to post-weld heat treatment (PWHT) time. The microstructure during the manufacture, laser welding, and PWHT was analyzed using field-emission scanning electron microscopy, X-ray diffraction, and electron backscatter diffraction, and the chemical composition was analyzed using dispersive X-ray spectroscopy and electron probe micro-analysis. The PWHT increased the volume fraction of austenite from 5% to 50% over 3 min at 1200 °C; this increased the OCP from −0.21 V to +0.03 V, and increased the CPT from 56 °C to 73 °C. The PWHT effectively improved the corrosion resistance, laying the groundwork for utilizing SAF 2507 in battery case materials. But the alloy segregation and heterogeneous grain morphology after PWHT needs improvement. [ABSTRACT FROM AUTHOR]

The corrosion behavior of CoCrNi medium-entropy alloy (MEA) in the coastal marine environment polluted by excessive CO2 was investigated. Increasing NaHCO3 concentration expediates the active dissolution of the passive film and damages its protectiveness. The positive half-cycle of AC increases local acidity and encourages Cl− to adsorb on the passivation film, whereas H+ ions are easily adsorbed during the AC-negative half-cycle. H+ and Cl− as aggressive ions can significantly undermine the stability and denseness of passivation film. Furthermore, the interactive effect of alternating current and HCO3− significantly interferes with the passivation of the MEA, contributes to the nucleation of metastable pitting, and increases the occurrence probability of stable pitting, aggravating anti-corrosion performance. The cathodic reaction under the influence of alternating current is dominated by hydrogen evolution; the generated hydrogen atoms can tear the passivation film and deteriorate the corrosion resistance. [ABSTRACT FROM AUTHOR]

The corrosion behavior of Q345qNH steel and Q420qNH steel in simulated industrial atmospheric environment medium was studied by periodic immersion+infrared aging corrosion experiment. The results show that the corrosion type of both samples is uneven comprehensive corrosion, and the rust layer formed in the later stage of corrosion is relatively dense. But average corrosion rate of Q345qNH steel is always lower than that of Q420qNH steel, and the ratio of Iα‐FeOOH/Iγ‐FeOOH in rust layer is always higher. Compared with Q420qNH steel, Q345qNH steel has fewer surface pits but deeper local pits. The self‐corrosion potential of Q345qNH steel increases obviously, the resistance of the rust layer is larger, and protection to the matrix is stronger. This is because the formation of a large number of corrosion microcells induced by fine lamellar sorbite tissue that uneven distributed in Q420qNH steel, which increases the corrosion rate and makes corrosion uneven, while the larger pearlitic group in Q345qNH steel increases the local corrosion rate. However, the higher chromium/carbon ratio in Q345qNH steel promotes the conversion of lepidocrocite to goethite and inhibits the cathode reaction in the infrared drying stage, improving the density and stability of the rust layer. [ABSTRACT FROM AUTHOR]

The corrosion behaviors of three bridge steels in a real tropical marine environment for 2 years were studied. One weathering steel (WS) was designed with higher levels of nickel, copper, and molybdenum compared to the other. These two kinds of WSs and one kind of ordinary high-strength low-alloy steel (Q345qe) were compared under two conditions (marine atmospheric zone and marine immersion zone at Sanya Marine Environmental Test Station). The morphology, corrosion rate, and corrosion product analysis of the steels were performed through SEM, XPS, FTIR and other characterization methods. The results demonstrated that weathering steels facilitate the densification of the corrosion product layer due to the addition of alloying elements Cr, Ni, and Cu, promoting rust nucleation and enhancing the compactness of the protective layer. However, in an immersion environment, the extensive erosion by chloride ions renders the benefits of WS ineffective. [ABSTRACT FROM AUTHOR]

This study aims to investigate the combined effect of Sc micro-alloying and applying low-frequency electromagnetic casting (LFEC) on precipitation behavior, mechanical and corrosion properties of 7A36 aluminum alloy. The results indicate that when compared to the T6 state, the two-stage over-aging (T73) treatment causes the transformation of the grain interior η′ phases into coarser η′ and η phases and leads to a more distinct appearance of precipitate free zone (PFZ). The addition of Sc results in the discontinuous and coarser formation of grain boundary precipitates (GBPs), and the Al3(Sc, Zr) phase particles contributes to the increased strength of 7A36 aluminum alloy. LFEC promotes the finer second phase and a finer distribution of grain interior precipitates, and dislocation movement bypasses a shorter distance and less energy is consumed, thus strength is decreased slightly. Meanwhile, the wider PFZ and the greater distribution spacing of the coarse GBPs contribute to a smaller intergranular fracture tendency, that's improve elongation of T6 and T73 alloys by 56.4% and 22.5% respectively, and contribute to improve corrosion resistance by blocking of intergranular corrosion channels. Based on the precipitation evolution, the synergy mechanism of Sc micro-alloying and LFEC processing is put forward in this paper. [ABSTRACT FROM AUTHOR]

Basalt powder (BP) is the residue of a plant that crushes basalt stones. This work deals with the effect of waste BP on the properties of cement mortars and the physical properties of hardened mortars. Modified concrete was prepared by partial replacement of BP in amount of 5, 10, 20% by weight of cement. Physico-mechanical properties and corrosion resistance were investigated. Electrochemical impedance spectroscopy (EIS) was used to examine the corrosion behavior of cement pastes with a partial addition of basalt powder in aggressive solutions of 5% NaCl and 5% MgCl2 for up to 270 days. Infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also performed to investigate the hydration process and microstructure formation of the basalt blended paste. Results indicate that the addition of basalt powder as a partial replacement of cement influences the microstructure of the interfacial transition zone (ITZ), which is denser and stronger than in cement paste without basalt powder. The filler effect of the basalt powder improves the compressive strength of cement paste. Also, comparing BP0 and BP20 in 5% NaCl after 270 days, the partial substitution of cement with BP resulted in a higher compressive strength of 671 and 895 kg/cm2, respectively. The EIS results also showed the highest values of Rp 953 ohms cm2 after 270 days. This high corrosion resistance might indicate the binding by high Al2O3 that reduced the free aggressive chloride ions in the solution. Article Highlights: The addition of basalt powder as a partial replacement of cement, improved the compressive strength of the concrete. The physicochemical and mechanical investigations showed that the basalt addition led to physical densification and more ITZ robust of cement matrix. EIS measurements showed that BP20 sample in 5% NaCl had a high Rp, 953 ohms cm2 after 270 days indicated higher corrosion resistance. [ABSTRACT FROM AUTHOR]

Highlights Supercritical CO2 (sc‐CO2) was widely used in CO2 flooding projects to enhance the recovery efficiency recently owing to its amazing dissolving capability and permeability. Fiber reinforced pipe (FRP) has exceptional properties that may be widely used in the petrochemical sector for transportation of corrosive fluid in CO2 flooding projects. In this research, a system was designed to simulate the transport behavior of fluids containing CO2 which can reaches the supercritical state by the adjustment of pressure and temperature. The fluid penetrates into the resin interior through the pores and gathers in the cavities at 65°C and 8 MPa. When the temperature and pressure are below the critical point, the CO2 volume expands dramatically, causing inter‐layered micro‐crack. When the environmental conditions repeatedly change above and below the critical point, these cracks will continue to propagate along the fiber arrangement direction, resulting in the fracture progressively grow into the delamination. At the same time, the fluid corrodes the resin in some areas of the surface, generating pitting and a 0.66% loss in resin content. The composition of elements and groups altered after corrosion revealed that a chemical interaction occurred between fluid and epoxy resin. Finally, due to physical and chemical processes produced by penetration, expansion, and dissolution, the stiffness of FRP fell by 3.53% during treatment. In the present work, a reactor coated with polytetrafluoroethylene (PTFE) was built to model the corrosion of FRP in delivery fluids containing sc‐CO2. The corrosion mechanism was shown as a combination action by chemical react and physical behavior comprising penetration, expansion and dissolution. The physical corrosion mechanism of fluid containing sc‐CO2 was investigated. The fluid containing sc‐CO2 penetrated the FRP via pores and accumulated in cavities. The quick expansion of sc‐CO2 causes delamination while the ambient circumstances remain below the critical threshold. The pitting and resin loss can be linked to the epoxy resin solution in supercritical CO2. The chemical process, known as hydrolysis, took place on the interior surface of epoxy resin and a fluid containing supercritical CO2. This finally resulted in molecular structural modification. [ABSTRACT FROM AUTHOR]

In this study, the CMAS corrosion behavior of two high-yttria-stabilized zirconia thermal barrier coatings (38YSZ and 55YSZ) deposited by air plasma spraying is investigated and compared with a typical 8YSZ coating at 1250 °C to unravel the underlying corrosion mechanism. The 8YSZ coating undergoes severe CMAS attack driven by dissolution-reprecipitation and intergranular corrosion. However, the 38YSZ and 55YSZ coatings can react with CMAS melt vigorously to form a dense reaction layer with CMAS-resistant apatite phase at the CMAS/coating interface, thereby resisting the CMAS infiltration. The apatite phase can be formed only when the yttria content in c-ZrO 2 precipitated from CMAS attains the critical value (∼20 at%). Moreover, compared to the 38YSZ coating, apart from the high yttria content, the low zirconia content in the 55YSZ coating also allows higher free Y3+ available to form apatite phase via inhibiting the formation of c-ZrO 2 , thus facilitating the formation of more apatite phase. [ABSTRACT FROM AUTHOR]

The corrosion behavior of novel MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories was investigated as a potential replacement for traditional MgO–MgAl 2 O 4 refractories as the inner lining of RH snorkels. The incorporation of Mg 1.08 Al 1.84 Ti 0.08 O 4 fine powder with dense microstructure resulted in superior densification and mechanical strength compared to traditional MgO–MgAl 2 O 4 refractories. The novel MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories significantly enhanced their corrosion resistance, due to the reduction in porosity and pore diameter, as well as the increase in pore complexity and contact angle. These factors effectively impeded the penetration of RH slag. Additionally, the presence of Mg 1.08 Al 1.84 Ti 0.08 O 4 in contact with RH slag formed a more complex (Mg, Fe)(Al, Ti) 2 O 4 spinel solid solution, which exhibited strong Fe element absorption ability. Thus, this decreased the Fe concentration in the RH slag, resulting in an increase in liquid slag viscosity and enhancing the slag penetration resistance of MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories. The microstructure of the MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories featured an isolated distribution of Ca 2 SiO 4 phase, which suggested fewer channels for liquid RH slag to penetrate the refractory materials. According to Factsage 6.2 thermodynamic simulation, the dissolution of Mg 1.08 Al 1.84 Ti 0.08 O 4 into liquid slag was lower compared to the sintered MgAl 2 O 4 , which was advantageous for resisting the dissolution of refractory materials into liquid slag. [ABSTRACT FROM AUTHOR]

This study investigates the corrosion behavior of laser beam-welded UNS S32304 and SS304L in 3.5% NaCl solutions, focusing on the effects of temperature. The primary objective is to enhance the understanding of corrosion resistance in welded materials and inspire advancements in corrosion mitigation strategies. The methodology involves assessing corrosion resistance under varying temperatures and comparing the performance of laser beam welding (LBW) with that of the base metals. Scanning electron microscopy analysis reveals effective passivation, while quantitative analysis indicates differences in chloride ion coverage between the weld metal and base metals. Tafel plots and electrochemical impedance spectroscopy demonstrate enhanced corrosion potential and improved barrier properties for the weld metal. Results indicate a marginal reduction in corrosion resistance at 50 °C for both base metals. LBW metals corrosion resistance demonstrates superior performance, with only 5% reduction in breakdown potential compared to 10% in base metals. Compared to the base metal, it exhibits a substantial reduction in corrosion rate, ranging from 60 to 75%. This supports enhanced corrosion resistance and material stability. Additionally, similar results are observed after the analysis with scanning electron microscopy images, reinforcing the efficacy of LBW in improving corrosion resistance of LBW UNS S32304 and SS304L. These findings underscore the potential of LBW for applications requiring robust corrosion performance. By contributing to the understanding of the corrosion behavior of laser beam-welded materials, this study addresses a critical research gap in material science and corrosion engineering. Future research may explore long-term durability and corrosion resistance under diverse environmental conditions to further elucidate the mechanisms driving the observed differences in corrosion behavior. [ABSTRACT FROM AUTHOR]

Purpose: Wire arc additive manufacturing (WAAM) is one of the most researched and fastest-growing AM technique because of its capability to produce larger components with medium complexity. In recent times, the use of WAAM process has been increased because of its ability to produce complex components economically when compared with other AM techniques. The purpose of this study is to investigate the capabilities of wire arc additive manufacturing (WAAM), which has emerged as a recognized method for fabricating larger components with complex geometries. Design/methodology/approach: This paper provides a review of process parameters for optimizing and analyzing mechanical properties, hardness, microstructure and corrosion behavior achieved through various WAAM-based techniques. Findings: Limited analysis exists regarding the mechanical properties of various orientations of Inconel 625 alloy. Moreover, there is a lack of studies concerning the corrosion behavior of Inconel 625 alloy fabricated using WAAM. Originality/value: The review identifies that the formation of intermetallic phases reduces the desirability of mechanical properties and corrosion resistance of WAAM-fabricated Inconel 625 alloy. Additionally, the study reported notable results obtained by various research studies and the improvements to be achieved in the future. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the corrosion behavior of cold-rolled Fe35Ni20Cr12Mn(28-x)Alx high-entropy alloys (HEAs) using the potentiodynamic polarization technique in 1 M H2SO4 acid. Additionally, the influence of molybdenum (Mo) additions as inhibitors and the effect of variations in cold rolling reduction ratios and Al content on corrosion behavior are examined. Design/methodology/approach: Two cold rolling reduction ratios, namely, 50% (R50) and 90% (R90), were examined for the cold-rolled Fe35Ni20Cr12Mn28Al5 (Al5) and Fe35Ni20Cr12Mn23Al10 (Al10) HEAs. Mo inhibitor additions were introduced at varying concentrations of 0.3, 0.6 and 0.9 Wt.%. The potentiodynamic polarization technique was used to evaluate the corrosion rates (CRs) under different experimental conditions. Findings: The results indicate that the addition of 0.3 Wt.% Mo in 1 M H2SO4 yielded the lowest CR for both R50 and R90, irrespective of the Al content in the HEAs. However, the highest CR was observed at 0.6 Wt.% Mo addition. Furthermore, increasing the concentration of Al resulted in a corresponding rise in the CR. Comparatively, the CR decreased significantly when the cold rolling reduction ratio increased from R50 to R90. Originality/value: This research provides valuable insights into the intricate relationship between Mo inhibitors, cold rolling reduction ratio, Al content and the resulting corrosion behavior of Fe35Ni20Cr12Mn(28-x)Alx HEAs. The comprehensive analysis of corroded HEAs, including surface morphology, compositions and elemental distribution mapping, contributes to the understanding of the corrosion mechanisms and offers potential strategies for enhancing the corrosion behavior of HEAs. [ABSTRACT FROM AUTHOR]

This work systematically studied the corrosion behavior and passivation property of CoCrFeNi high‐entropy alloys (HEAs) in a simulated seawater environment. The results reveal that the addition of CO32−/HCO3− results in the secondary passivation of the HEA in NaCl solution, and secondary passivation film possesses higher dissolution rate in comparison with primary passive film. H+ ions ionized by HCO3− facilitate the charge transfer process, thin the thickness of passive film, and increase the disordered degree of the film. Moreover, the presence of HCO3− promotes the nucleation and growth of metastable pits, and enhances the pitting sensitivity. Furthermore, an increase in CO32− concentration accelerates the dissolution of passive film, weakens the compactness and protective performance of the film, and increases the probability that metastable pitting evolves into stable pitting, as well aggravates the corrosion of the HEA. In addition, the corrosion resistance of the HEA is diminished due to the formation of microgalvanic corrosion cells between matrix and inclusion. The selective dissolution of elements occurred in the HEA. [ABSTRACT FROM AUTHOR]

The corrosion behavior of 310S austenitic stainless steel, subjected to different surface treatments machined (MA), sandblasting (SB), and polishing (PO), was exposed to a 550°C supercritical water (SCW) environment. The aged samples were analyzed using variable‐energy slow positron beam techniques. The obtained results revealed that the plastic deformation of the near‐surface region of the MA and SB samples was substantially recovered in the SCW conditions. At least two distinct oxide layers formed, and the oxidation process created a Fe/Cr depletion zone in the inner layer. Various surface treatments, however, led to different corrosion profiles. The depth profile of slow positron beam characterization suggests that significant residual stress and deformation zones on the surfaces of the sandblasted samples probably provided a diffusion path for the oxidation of the 310S. Only the SB samples exhibited a negative weight change after SCW exposure. At the same time, the SB samples showed the highest concentration of the positron traps in this region, which was explained by open‐volume defects associated with the microcracks introduced by sandblasting. [ABSTRACT FROM AUTHOR]

Since F/M steel is one of the leading candidate materials for the lead-cooled fast reactor (LFR), its compatibility with the liquid LBE environment is an essential issue before application. One major way to improve LBE corrosion resistance is to control the oxygen concertation in liquid LBE for the growth of a stable, protective oxide layer on the surface of the structure material. However, the influence of the surface state on corrosion behavior is a more realistic issue when it comes to practical applications. In this study, the corrosion behavior of Si-reinforced 9Cr and 11Cr F/M steels with different surface states was investigated by a static liquid LBE corrosion test under solid-phase oxygen-controlled conditions. The result showed that at 550 °C, the coarse surface state caused dissolution behavior at the initial stage of corrosion, while the fine surface state formed the oxide layer. Moreover, at 610 °C, Si-reinforced 11Cr F/M steel shows better liquid LBE corrosion resistance due to its thinner oxide layer formation. [ABSTRACT FROM AUTHOR]

The demand for low elastic modulus and biocompatible load-bearing implants has experienced a significant surge in recent times. Gum metal, a noteworthy category of β-Ti alloys, has gained substantial recognition in the biomedical field. This is primarily attributed to its remarkable blend of characteristics, encompassing non-toxic and biocompatible elements, a low elastic modulus, superelasticity, and high strength. Achieving these properties involves precise electronic criteria within their composition and substantial deformation, often through cold swaging. Recent years have seen innovative processing methods and alloy compositions to meet these requirements, expanding Gum metal's properties and applications. This review offers a thorough look at Gum metal, covering its discovery and highlighting its unique properties, with a particular focus on its relevance in the biomedical field. It critically analyzes the various phases of Gum metal and delves deeply into its deformation mechanism, unveiling its exceptional shape recovery capability even after significant deformation. Theoretical alloy design strategies for Gum metal are addressed, providing a glimpse into the ongoing efforts to optimize its performance for biomedical applications. The impact of oxygen on the Gum metal's properties is explored. The review also scrutinizes biocompatibility and corrosion behavior studies conducted on Gum metal, emphasizing its appropriateness for biomedical implants. Finally, various fabrication and processing routes for Gum metal are reviewed, offering insights into the techniques employed to harness its potential for practical applications. [ABSTRACT FROM AUTHOR]

This article aims to investigate aging temperature effects on the wear and corrosion characteristics of stainless steel alloy Custom 450. Electrochemical measurements were performed in 1 M H2SO4 solution. Pin-on-disk tests and microstructural evaluations were also done. The results displayed that the steel hardness increased when the aging temperature was raised to 500 °C. However, higher temperatures resulted in a hardness reduction of about 11% compared with annealed specimens. Such observation was due to the increase in the reversed austenite content by up to 10.7%. The aged specimen's wear rate was reduced by about 85% when the aging temperature was 500 °C, based on the high hardness. The suggested wear mechanism changed from abrasive and cutting wear mode to the adhesive wear mechanism when the aging temperature increased. Tafel polarization tests showed that corrosion rates of specimens decreased by about 99% when the aging temperature increased to 600 °C. This was attributed to increasing the amount of the reversed austenite phase, and Ni-rich precipitates in the aged martensite matrix. [ABSTRACT FROM AUTHOR]

The non-equiatomic Al0.32CrFeTi0.73(Ni1.50−xMox) (x = 0, 0.23) high-entropy alloy (HEA) coatings were prepared by the high-velocity oxygen fuel (HVOF) method. The microstructures and corrosion behaviors of the HVOF-prepared coatings were investigated. The corrosion behaviors were characterized by polarization, EIS and Mott-Schottky tests under a 3.5 wt.% sodium chloride aqueous solution open to air at room temperature. The Al0.32CrFeTi0.73Ni1.50 coating is a simple BCC single-phase solid solution structure compared with the corresponding poly-phase composite bulk. The structure of the Al0.32CrFeTi0.73Ni1.27Mo0.23 coating, combined with the introduction of the Mo element, means that the (Cr,Mo)-rich sigma phase precipitates out of the BCC solid solution matrix phase, thus forming Cr-depleted regions around the sigma phases. The solid solution of large atomic-size Mo element causes the lattice expansion of the BCC solid solution matrix phase. Micro-hole and micro-crack defects are formed on the surface of both coatings. The growth of both coatings' passivation films is spontaneous. Both passivation films are stable and Cr2O3-rich, P-type, single-layer structures. The Al0.32CrFeTi0.73Ni1.50 coating has better corrosion resistance and much less pitting susceptibility than the corresponding bulk. The corrosion type of the Mo-free coating is mainly pitting, occurring in the coating's surface defects. The Al0.32CrFeTi0.73Ni1.27Mo0.23 coating with the introduction of Mo element increases pitting susceptibility and deteriorates corrosion resistance compared with the Mo-free Al0.32CrFeTi0.73Ni1.50 coating. The corrosion type of the Mo-bearing coating is mainly pitting, occurring in the coating's surface defects and Cr-depleted regions. [ABSTRACT FROM AUTHOR]

This work systematically studied the corrosion behavior and passivation property of CoCrFeNi high‐entropy alloys (HEAs) in a simulated seawater environment. The results reveal that the addition of CO32−/HCO3− results in the secondary passivation of the HEA in NaCl solution, and secondary passivation film possesses higher dissolution rate in comparison with primary passive film. H+ ions ionized by HCO3− facilitate the charge transfer process, thin the thickness of passive film, and increase the disordered degree of the film. Moreover, the presence of HCO3− promotes the nucleation and growth of metastable pits, and enhances the pitting sensitivity. Furthermore, an increase in CO32− concentration accelerates the dissolution of passive film, weakens the compactness and protective performance of the film, and increases the probability that metastable pitting evolves into stable pitting, as well aggravates the corrosion of the HEA. In addition, the corrosion resistance of the HEA is diminished due to the formation of microgalvanic corrosion cells between matrix and inclusion. The selective dissolution of elements occurred in the HEA. [ABSTRACT FROM AUTHOR]

In the present work, a wall-structured nickel-aluminum bronze (NAB) alloy was fabricated via electron beam directed energy deposition (EB-DED) additive manufacturing with a single-pass multi-layer deposition strategy. A comprehensive comparative analysis of microstructure, mechanical properties, and corrosion resistance was conducted against a conventionally cast NAB alloy. The inherent rapid solidification and cyclic thermal processing of the EB-DED technique profoundly influenced the microstructural evolution of the NAB alloy. The as-deposited NAB alloy exhibited a fine-grained microstructure, devoid of the martensitic β′ phase, accompanied by the spheroidization of partial κIII precipitates, and a homogeneous distribution of alloying elements. These distinctive microstructural attributes synergistically enhanced the strength, hardness, and toughness of the NAB alloy, conferring superior mechanical properties compared to its cast counterpart. Furthermore, the as-deposited alloy demonstrated remarkable corrosion resistance in a 3.5 wt% NaCl solution, significantly outperforming the cast alloy. The underlying mechanisms governing the structure-property relationships were elucidated. This comprehensive investigation provided insights into the unique characteristics and potential applications of EB-DED fabricated NAB alloys, positioning them as promising candidates for high-performance components subjected to severe mechanical and corrosive service conditions.

In order to create a cost-effective Zr alloy with superior overall characteristics, Zr-xFe (x = 0, 2, 4, 6, 8, 10 at.%) binary alloys were prepared by a vacuum arc furnace system. The microstructure of these alloys was examined utilizing various techniques such as optical microscope, X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy. The results showed that the addition of Fe effectively refined α-Zr slats, and the Zr3Fe compound phase was dispersed throughout the alloy. However, the composition line of the alloying elements in the phase diagram intersected with the Zr2Fe and β-Zr eutectic lines when the Fe content exceeded 6 at.%. Zr–Fe alloys were transformed from monocrystalline-eutectoid to eutectic-eutectoid reactions. The Zr3Fe compound phase accumulated inside the grain and at the grain boundary as a result of the eutectic reaction, which stabilized the microstructure of the Zr–Fe alloys. This seriously affected the mechanical and corrosion properties of the alloys. The mechanical and corrosion properties of the alloys were assessed by universal testing machine, dynamic microhardness tester, Vickers hardness tester, and electrochemical workstation. The mechanical and corrosion properties of Zr–2Fe were excellent due to the coupling effect of Zr3Fe and grain refinement. The surface of the Zr–Fe alloy was analyzed by X-ray photoelectron spectroscopy, revealing the presence of passivation film components ZrO2 and Fe2O3.

Nickel-base alloy is a type of metal material with excellent properties and is widely used in many fields. However, in the harsh environment of the acid solution, corrosion causes the reduction of the service life of the alloys, thereby limiting the alloys' use and development. In this paper, the effect of Chromium (Cr) content on the microstructure and corrosion behavior of nickel-based alloys in hydrochloric acid (HCl) was studied by scanning electron microscopy (SEM), energy dispersive spectrum (EDS), electron backscatter diffraction (EBSD) and electrochemical workstation. Meanwhile, X-ray photoelectron spectroscopy (XPS) was used to investigate the composition and properties of the surface passive films. For the Cr20 and Cr30 alloys with a single face-centered cubic (FCC) structure, the Cr2O3 content in the passive films increased with the Cr content, effectively improving the corrosion resistance. As the Cr content continued to increase, the second phases having a body-centered cubic (BCC) lattice were precipitated both in the Cr40 and Cr50 samples, inducing microgalvanic corrosion, thus deteriorating the corrosion resistance. XPS results showed that, in the Cr30 alloy, the relative content of Cr2O3 and the bound water were the highest, indicating that its passive film had the best corrosion resistance. For the passive film, the pitting resistance was related to Cr content, appropriate Cr content improved the corrosion resistance.

This study investigates the corrosion characteristics of Co30Cr20Ni20Fe20Mo10 (Co30HEA), Co40Cr20Ni15Fe15Mo10 (Co40HEA), and Co50Cr20Ni10Fe10Mo10 (Co50HEA), designed as Co-rich high entropy alloys, compared to 316 L stainless steel and L605. Co30HEA has a single FCC phase, whereas the other two alloys exhibit a dual phase of FCC + (Cr, Mo) σ phase. The presence of high Cr and Mo content in the σ phase results in Cr depletion zones. Co30HEA shows the highest corrosion resistance in Ringer's solution, which diminishes with increasing Co content. Its passive film exhibits ideal capacitive behavior at low frequencies, indicating strong passivation. The films, primarily composed of Cr oxides and hydroxides, vary in thickness, with Co30HEA having a film about twice as thick as the others. All three alloys demonstrate pitting corrosion; however, Co30HEA shows the smallest pits mainly at grain boundaries, while the others show pits near the σ phase due to unstable passive films in the Cr and Mo-depleted zones, acting as anodic sites for galvanic corrosion.

Abstract This study investigates the corrosion behavior of laser beam-welded UNS S32304 and SS304L in 3.5% NaCl solutions, focusing on the effects of temperature. The primary objective is to enhance the understanding of corrosion resistance in welded materials and inspire advancements in corrosion mitigation strategies. The methodology involves assessing corrosion resistance under varying temperatures and comparing the performance of laser beam welding (LBW) with that of the base metals. Scanning electron microscopy analysis reveals effective passivation, while quantitative analysis indicates differences in chloride ion coverage between the weld metal and base metals. Tafel plots and electrochemical impedance spectroscopy demonstrate enhanced corrosion potential and improved barrier properties for the weld metal. Results indicate a marginal reduction in corrosion resistance at 50 °C for both base metals. LBW metals corrosion resistance demonstrates superior performance, with only 5% reduction in breakdown potential compared to 10% in base metals. Compared to the base metal, it exhibits a substantial reduction in corrosion rate, ranging from 60 to 75%. This supports enhanced corrosion resistance and material stability. Additionally, similar results are observed after the analysis with scanning electron microscopy images, reinforcing the efficacy of LBW in improving corrosion resistance of LBW UNS S32304 and SS304L. These findings underscore the potential of LBW for applications requiring robust corrosion performance. By contributing to the understanding of the corrosion behavior of laser beam-welded materials, this study addresses a critical research gap in material science and corrosion engineering. Future research may explore long-term durability and corrosion resistance under diverse environmental conditions to further elucidate the mechanisms driving the observed differences in corrosion behavior.

The effect of utilization of zinc (Zn) and graphite (Gr) as a hybrid interlayer for dissimilar lap joint of AA2024 and pure copper, employing friction stir welding (FSW), was investigated in this study. The microstructure of the samples was examined using a scanning electron microscope (SEM), and the composition of the present phases was evaluated with energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were performed to analyze the corrosion behavior. Subsequently, the post-corrosion morphology was examined using SEM and EDS. The results show that applying two passes of FSW in the presence of hybrid Zn-Gr interlayer, led to the modification of detrimental brittle intermetallic compounds (IMCs). The corrosion investigations demonstrated that the corrosion current density (icorr) in the AA2024/(Zn-Gr)/Cu sample after 1- pass FSW was reduced by about 80% in comparison to the Al/Zn/Cu sample. This behavior can be attributed to the presence of a large number of diffusion channels and the inhibitory effect of graphite particles. The 2-pass FSWed AA2024/(Zn-Gr)/Cu sample exhibited the highest level of corrosion resistance, owing to the better dispersion of graphite particles, which led to improved passivation on the aluminum side. As a result, the inherent issue of intergranular corrosion in the Al–Cu alloy was effectively resolved at the joint interface. This ultimately led to an enhanced corrosion resistance of the Al–Cu bimetals produced by FSW.

In this study, magnetron sputtered carbothermic reduced iron boride (FeB) coatings were developed on grey cast iron (GCI) substrates at different substrate temperatures. The impact of substrate temperature on structural, mechanical, and corrosion behavior was examined for two FeB deposition scenarios: FeB coatings deposited at room temperature (RT) and at 500 °C substrate temperature. The evolution of phases and microstructure was studied using XRD and FESEM, respectively. The mechanical properties, creep, deformation behavior, and adhesion strength (scratch test) of the deposited coatings were investigated using nanoindentation at ambient temperature. The highest hardness and Young's modulus of 16 GPa and 231 GPa respectively, were achieved at 500 °C due to microstructural enhancement. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion behavior of the coatings. The results show that substrate temperature strongly influences the surface morphology of the coatings, which in turn governs the mechanical and corrosion behavior of the FeB coating. The FeB-coated GCI at 500 °C substrate temperature showed higher resistance to scratching, better mechanical properties, and improved corrosion resistance which is attributed to the enhanced adhesive strength, refined microstructure, and formation of protective oxide layers of FeB on the surface of the coatings. [Display omitted] • FeB coatings have a hardness of 11.8 GPa, an elastic modulus of 165 GPa at RT, and 15.6 GPa and 231 GPa at 500 °C. • The FeB coating showed conformal cracking at RT and tensile cracking at 500 °C, indicating better adherence at 500 °C. • At 500 °C, the FeB coating displayed improved corrosion resistance and reduced corrosion current density. • EIS data revealed higher charge transfer resistance and a larger semicircle arc for the FeB coating at 500 °C compared to RT. [ABSTRACT FROM AUTHOR]

Corrosion of steel bars embedded in reinforced concrete structures considerably reduces the service life and even causes early failure of the structure. This paper investigates the early corrosion behavior of an alloy corrosion-resistant steel bar in seawater–sea sand concrete (SWSSC) using various electrochemical measurements [electrochemical impedance spectroscopy (EIS) linear polarization resistance (LPR)] and surface characterization techniques [scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS)], in comparison to low carbon steel bar (LC) and stainless steel bar (SS). The results reveal that the Cr10Mo1 alloy corrosion-resistant steel bar (CR) in SWSSC shows significant increase in the radius of the capacitive arc in later stages, particularly in the low frequency region. This increase in CR can be attributed to the enhanced corrosion resistance of the passivation film, as well as the rise of impedance at the interface between the passivation film and the concrete matrix. These improvements have effectively inhibited the penetration of free chloride ions into the concrete, thereby impeding the initiation and propagation of corrosion in CR In addition, the mechanical properties, pore structure and the hydration production of SWSSC were investigated. Based on the interactions between steel substrate and concrete matrix, the possible resistance mechanism of CR was proposed. This study innovatively provides a comprehensive evaluation of the effectiveness of CR in SWSSC. [ABSTRACT FROM AUTHOR]

In historical reinforced concrete buildings, square ribbed rebars, round ribbed rebars and square twisted rebars are the main steel rebars. In order to determine the corrosion behavior of such historical steel rebars, we investigated the deterioration mechanisms of steel rebars in historical architecture in simulated concrete pore solution using various electrochemical tests and microscopic examination of corrosion products. The hot-rolled ribbed bar (HRB)335 rebars used in modern buildings were used as a control sample. The results demonstrated that the corrosion process of the historical rebars was similar to that of HRB335 rebars. Nevertheless, there were some differences in the chemical composition, microstructure, passive film characteristics, critical chloride ion concentration, and corrosion products. In the passivation stage, the stability order of the passive film generated on the surface of the rebars was as follows: square ribbed rebars > square twisted rebars > HRB335 rebars > round ribbed rebars. In the Cl− corrosion stage, the damaging effect order of Cl− on the passive film is square ribbed rebars > HRB335 rebars > square twisted rebars > round ribbed rebars. The critical chloride ion concentration was between 0.5% and 2.0% by weight. The corrosion products were mainly Fe2O3 , α -FeOOH, γ -FeOOH. β -FeOOH, and protective Fe3O4. The corrosion products of HRB335 rebars were mainly nonprotective crystallized FeOOH with various morphologies. The results of this study provide a scientific foundation for the conservation design and residual life prediction of historic reinforced concrete buildings. [ABSTRACT FROM AUTHOR]

A liquid-repellent and corrosion resistant surface was fabricated on AZ31B Mg alloy by the usage of CeO 2 and TiO 2 nanoparticles (NPs), plasma electrolyte oxidation (PEO) method, and subsequent surface modification. The whole process included two main steps: a) applying PEO with CeO 2 –TiO 2 NPs on AZ31B and b) decreasing surface energy by using a fluorinating agent. Elements that were present on the surface were investigated by XRD and EDS analyses. Surface morphology and its roughness were scrutinized by FESEM images and AFM tests, respectively. Contact angles (CA) of water and some oils (Ethylene glycerol and Glycerol) on the prepared surface were measured. CAs of water and ethylene glycerol were reported at 175.6° and 151.4°, respectively. Also, the corrosion behavior of the prepared surface was assessed by EIS and potentiodynamic polarization analyses. Results showed that the corrosion rate of the neat AZ31B decreased noticeably from 127.78 to 0.027 mpy for superamphiphobic PEO-NPs AZ31B. The prepared sample showed high mechanical durability, which was scrutinized by water floatation, abrasive with grit SiC paper, adhesive tape peeling, and bending tests. After immersion of the sample in 5 wt% NaCl solution for various hours, results showed that the prepared sample had a noticeable corrosion resistance stability. [Display omitted] • A durable superamphiphobic surface was fabricated on AZ31B. • The prepared surface showed a remarkable water and oil repellency. • A prepared superamphiphobic surface promoted noticeably the corrosion resistance of AZ31B. • A superamphiphobic surface showed brilliant corrosion resistance stability and mechanical durability. [ABSTRACT FROM AUTHOR]

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To address the current issues of brittleness and lower mechanical performance for Zn alloys, the Zn–Mn–Li system that has significant potential for enhancing strength and toughness is selected for the design, fabrication, and investigation. Li and Mn are selected as alloying elements, and a series of Zn-0.4Mn-xLi alloys are prepared. A comprehensive study of as-cast alloys is conducted on the microstructure, mechanical properties, and corrosion behavior. The results reveal that the initially precipitated β-LiZn4 phase in the as-cast Zn-0.4Mn-xLi alloys gradually transforms into a β-LiZn4/Zn lamellar structure with the increase of Li content. The β-LiZn4/Zn lamellar structure significantly contributes to the strength of the alloy. The as-cast Zn-0.4Mn-0.8Li alloy exhibits optimal mechanical strength, with yield strength and ultimate tensile strength of 203.2 ± 8.9 MPa and 271.5 ± 20.0 MPa, respectively. Electrochemical and immersion experiments indicate a dense Li-rich corrosion product layer formed on the alloy surface suppresses the generation of pitting corrosion and enhances the corrosion resistance of the alloy. These results manifest that the Li content of the Zn–Mn–Li alloy has a significant influence on the performance, such as the microstructure, mechanical properties, and corrosion behavior. According to the results of mechanical properties and corrosion behavior, Zn-0.4Mn-0.8Li alloy exhibits an optimal comprehensive performance, which provides valuable insight for the development of superior Zn–Mn–Li alloys.

Balancing mechanical and corrosion performance is a decisive factor in the use of high entropy and medium entropy alloys (H & MEAs) as advanced engineering structural materials. This study investigates the microstructure of Fe77.3-xMnxSi9.1Cr9.8C3.8 (x = 14, 23.2) HEAs by combining experiments and first-principles calculations to elucidate the effects of adjusting Mn content on the mechanical and corrosion properties of FCC and FCC + HCP phases. The results demonstrate that HEAs with low Mn content exhibit a single FCC phase, whereas increasing Mn content not only precipitates the HCP phase but also refines the grain size. The yield strength, compressive fracture strength, work hardening index, and plasticity of Fe77.3-xMnxSi9.1Cr9.8C3.8 (x = 14, 23.2 at.%) HEAs are 1300 and 1526 MPa, 2380 and 2332 MPa, 0.42 and 0.36, 16.7% and 16%, respectively. Both HEAs exhibit superior electrochemical and salt spray corrosion performance compared to 304 stainless steels, with the Fe63.3Mn14Si9.1Cr9.8C3.8 alloy performing the best, exhibiting a self-corrosion potential of −0.523V and a self-corrosion current density of 2.605 × 10−6 A cm−2. The excellent corrosion resistance of Fe63.3Mn14Si9.1Cr9.8C3.8 can be attributed to the moderate grain size, resulting in excellent passivation film characteristics, and the lower Mn content, leading to a higher Cr2O3 content in the passivation film. First-principles calculations reveal that Fe63.3Mn14Si9.1Cr9.8C3.8 has a lower density of states number at the Fermi level (i.e., Fe63.3Mn14Si9.1Cr9.8C3.8 is 214.145eV, Fe54.1Mn23.2Si9.1Cr9.8C3.8 is 337.077eV), a wider pseudogap width, higher work function (5.700ev, 5.189ev), and better stability. Additionally, there exists a strong trade-off between corrosion and mechanical properties due to the influence of the HCP phase and grain size.

Steel containers used for geological disposal of high-level radioactive waste will be gradually thinned or even perforated due to corrosion, which will lead to radiolysis of nuclides when they contact with infiltrated groundwater and produce H2O2. This work focused on investigating the influence of H2O2 concentration (0%, 0.001%, 0.01%, 0.1% and 1% by volume) on the corrosion behavior of NiCu low alloy steel as the candidate material for containers was comparatively studied by combining corrosion weight loss test, corrosion product analysis, morphology characterization, thermodynamic analysis and electrochemical measurements. As [H2O2] = 0.001%, H2O2 inhibited the formation of γ-FeOOH and enhanced the compactness of rust layer, which effectively blocked the migration of aggressive ions and slowed down the cathodic reduction reaction of rust, thus improving the corrosion resistance of NiCu steel. With the increase of [H2O2] (0.01%→1%), the cathodic process of NiCu steel corrosion was promoted by the increase of dissolved oxygen involved in cathodic depolarization. Meanwhile, the relative content of Fe3O4 in the rust increased, while Fe6(OH)12SO4 and Fe6(OH)12CO3 decreased obviously, which led to the loose and porous rust layer, thus accelerating the corrosion of NiCu steel.

Having homogenized the as-cast AlCoCrFeNi2.1 high-entropy alloy followed by cold rolling and subsequent annealing, this study produces surface nanocomposite using friction stir processing (FSP). Three weight percentages of SiC nanoparticles sized between 45 and 60 nm were added during FSP. The microstructural evolutions and corrosion behavior were assessed after and before FSP. As part of the investigation, a series of potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were conducted in a 3.5 wt% NaCl solution. Through friction stir processing, the initial microstructure underwent significant modification due to dynamic recrystallization and the Zener pinning applied by SiC-reinforcing nanoparticles. The hard B2 phases, which function as preferred sites for localized corrosion, were broken and redistributed during FSP, resulting in a notable increase in corrosion resistance. After performing FSP, the cold-rolled and annealed sample exhibited a significant increase in corrosion resistance, from 1.7 kΩ.cm2 to 129.4 kΩ.cm2.

Biodegradable pure Zn and zinc alloys have received much attention in recent years, but the mechanical properties, corrosion behavior and biocompatibility of the previous reported pure zinc and zinc alloys do not fully meet the clinical requirements. Alloying and deformation technology are widely used in improving the properties of biodegradable pure Zn and zinc alloys. In this work, we have developed two new types of binary zinc alloys with the two rare earth elements (REE) cerium (Ce) and ytterbium (Yb). The effects of Ce and Yb on the microstructure, mechanical properties, corrosion behavior, in vitro biocompatibility of biodegradable Zn-xCe and Zn-xYb (x = 0.1, 0.2, 0.5, 1.0 wt %) were systematically investigated. The ultimate tensile strength, yield strength and elongation of Zn-xCe and Zn-xYb alloys are significantly improved compared with pure Zn. The Zn-xCe and Zn-xYb alloys have superior antibacterial properties The osteoblast MC3T3-E1 cells exhibited excellent cell activity with polygonal or fusiform extension and adhesion cultured in the series of Zn-xCe and Zn-xYb alloys’ extract solutions, indicating the good in vitro biocompatibility of Zn-xCe and Zn-xYb alloys. This work demonstrated that the Zn-xCe and Zn-xYb binary alloys have great potential as new biodegradable metals for future biomedical implants and devices.