Research

15 pages, 7665 KiB

Open AccessArticle

Study on the Influence of Surface Treatment Process on the Corrosion Resistance of Aluminum Alloy Profile Coating

by Lei Fan, Fatao Wang, Zhouhui Wang, Xuelong Hao, Neng Yang and Denglin Ran

Materials 2023, 16(17), 6027; https://doi.org/10.3390/ma16176027 - 01 Sep 2023

Cited by 4 | Viewed by 897

This work focuses on different surface treatment processes of the 6061 aluminum alloy profile coatings in the construction industry, mainly including the sand powder film coating, the flat powder coating, the hard anodized film, and the ordinary heat-sealing oxidized coating. The corrosion resistance [...] Read more.

This work focuses on different surface treatment processes of the 6061 aluminum alloy profile coatings in the construction industry, mainly including the sand powder film coating, the flat powder coating, the hard anodized film, and the ordinary heat-sealing oxidized coating. The corrosion resistance of the coated aluminum alloy in a 3.5 wt.% NaCl solution (pH 6.5–7.5) and the influence of different surface treatment processes on the corrosion resistance of different samples were studied by scanning electron microscope (SEM) and electrochemical workstation. The result shows that with the increase in corrosion time, the corrosion inhibition performance of the four coated aluminum alloy materials decreased significantly, and the order of decline is: sand powder film coating > hard anodized film > flat powder coating > ordinary heat-sealing oxidized coating. When corroded in a 3.5 wt.% NaCl solution for 2 h, the corrosion inhibition performances of the flat powder coating and ordinary heat-sealing oxidized coating are poor, while the inhibition performances of the sand powder film coating and hard anodized film are good, and the inhibition performance follows the following sequence: the sand powder film coating > hard anodized film> the flat powder coating > ordinary heat-sealing oxidized coating. When corroded in a 3.5 wt.% NaCl solution for 200 h, the corrosion inhibition performances of the sand powder film coating and the flat powder coating are poor, while the inhibition performances of hard anodized film and ordinary heat-sealing oxidized coating are good, and the inhibition performance follows the following sequence: hard anodized film > ordinary heat-sealing oxidized coating > the sand powder film coating > the flat powder coating. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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12 pages, 4182 KiB

Open AccessArticle

Corrosion Passivation in Simulated Body Fluid of Ti-Zr-Ta-xSn Alloys as Biomedical Materials

by El-Sayed M. Sherif, Yassir A. Bahri, Hamad F. Alharbi and Muhammad Farzik Ijaz

Materials 2023, 16(13), 4603; https://doi.org/10.3390/ma16134603 - 26 Jun 2023

Cited by 1 | Viewed by 764

Abstract

The powder metallurgy method was used to manufacture three Ti-based alloys: Ti-15%Zr-2%Ta-4%Sn (Ti-Zr-Ta-4Sn), Ti-15%Zr-2%Ta-6%Sn (Ti-Zr-Ta-6Sn), and Ti-15%Zr-2%Ta-8%Sn (Ti-Zr-Ta-8Sn). Electrochemical measurements and surface analyses were used to determine the effect of Sn concentration on the corrosion of these alloys after exposure to a simulated [...] Read more.

The powder metallurgy method was used to manufacture three Ti-based alloys: Ti-15%Zr-2%Ta-4%Sn (Ti-Zr-Ta-4Sn), Ti-15%Zr-2%Ta-6%Sn (Ti-Zr-Ta-6Sn), and Ti-15%Zr-2%Ta-8%Sn (Ti-Zr-Ta-8Sn). Electrochemical measurements and surface analyses were used to determine the effect of Sn concentration on the corrosion of these alloys after exposure to a simulated body fluid (SBF) solution for 1 h and 72 h. It was found that the passivation of the alloy surface significantly increased when the Sn content increased from 4% to 6% and then to 8%, which led to a significant reduction in corrosion. The impedance spectra derived from the Nyquist graphs also explained how the addition of Sn significantly improved the alloys’ polarization resistances. According to the change in the chronoamperometric current at an applied anodic potential over time, the increase in Sn content within the alloy significantly reduced the currents over time, indicating that the uniform and pitting corrosion were greatly decreased. The formation of an oxide layer (TiO₂), which was demonstrated by the surface morphology of the alloys after exposure to SBF solution for 72 h and corrosion at 400 mV (Ag/AgCl) for 60 min, was supported by the profile analysis obtained by an X-ray spectroscopy analyzer. It was clear from all of the findings that the tested alloys have a remarkable improvement in resistance to corrosivity when the Sn content was increased to 8%. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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13 pages, 2988 KiB

Open AccessArticle

Preparation of Epoxy Resin with Disulfide-Containing Curing Agent and Its Application in Self-Healing Coating

by Baolei Wang, Zewei Li, Xinru Liu, Lulu Li, Jianxiang Yu, Shuang Li, Gaiping Guo, Dahai Gao and Yuhua Dai

Materials 2023, 16(12), 4440; https://doi.org/10.3390/ma16124440 - 16 Jun 2023

Cited by 3 | Viewed by 1267

Abstract

Intrinsic self-healing polymers via dynamic covalent bonds have been attracting extensive attention because of their repeatable self-healing property. Herein, a novel self-healing epoxy resin was synthesized with disulfide-containing curing agent via the condensation of dimethyl 3,3′-dithiodipropionate (DTPA) and polyether amine (PEA). Therefore, in [...] Read more.

Intrinsic self-healing polymers via dynamic covalent bonds have been attracting extensive attention because of their repeatable self-healing property. Herein, a novel self-healing epoxy resin was synthesized with disulfide-containing curing agent via the condensation of dimethyl 3,3′-dithiodipropionate (DTPA) and polyether amine (PEA). Therefore, in the structure of cured resin, flexible molecular chains and disulfide bonds were imported into the cross-linked polymer networks for triggering self-healing performance. The self-healing reaction of cracked samples was realized under a mild condition (60 °C for 6 h). The distribution of flexible polymer segments, disulfide bonds and hydrogen bonds in cross-linked networks plays a great role in the self-healing process of prepared resins. The molar ratio of PEA and DTPA strongly affects the mechanical performance and self-healing property. Especially when that molar ratio of PEA to DTPA is 2, the cured self-healing resin sample showed great ultimate elongation (795%) and excellent healing efficiency (98%). The products can be used as an organic coating, in which the crack could self-repair during a limited time. The corrosion resistance of a typical cure coating sample has been testified by an immersion experiment and electrochemistry impedance spectrum (EIS). This work provided a simple and low-cost route to prepare a self-healing coating for prolonging the service life of conventional epoxy coatings. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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17 pages, 5141 KiB

Open AccessArticle

LDH-Based “Smart” Films for Corrosion Sensing and Protection

by Xuejie Zhao, Yujie Yuan, Yuankun Wei, Zhe Zhang and You Zhang

Materials 2023, 16(9), 3483; https://doi.org/10.3390/ma16093483 - 30 Apr 2023

Cited by 2 | Viewed by 1439

Abstract

In a “smart” corrosion-protective coating system, both the active anti-corrosion and the early corrosion detection of underlying metals are highly required. It is practical significant to develop materials that possess self-detecting of the early local corrosion and self-healing of coating defects simultaneously. The [...] Read more.

In a “smart” corrosion-protective coating system, both the active anti-corrosion and the early corrosion detection of underlying metals are highly required. It is practical significant to develop materials that possess self-detecting of the early local corrosion and self-healing of coating defects simultaneously. The organic compound 8-hydroxyquinoline (8HQ) is an effective inhibitor and a fluorescent sensor probe for corrosion of aluminum alloy. Therefore, a layer double hydroxide (LDH) nanocontainer film loaded with the 8HQ was developed for the active corrosion protection purpose of aluminum alloy AA2024. In corrosive environments, the 8HQ are released from LDH film to inhibit the corrosion process, leading to the loss of the complexation with Al³⁺ ions in LDH laminates, thus turning off fluorescence. Results show that the LDH film loaded with 8HQ composites can improve the anti-corrosion performance of the film by releasing corrosion inhibitors on demand. Simultaneously, due to the complexation of 8HQ and Al³⁺ ions, the LDH film is fluorescent at the initial stage under ultraviolet light, and then becomes non-fluorescent at the corrosion sites, indicating the corrosion evolution process of the coating. The 8HQ-loaded LDH film with self-healing and self-detecting dual functions provides promising opportunities for the effective corrosion protection of aluminum alloy due to its “smart” and multifunctional properties. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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19 pages, 5397 KiB

Open AccessArticle

Synthesis, Microstructure Investigation, Mechanical and Tribological Behaviour of the AA5083–WC Composite

by Hany R. Ammar, Subbarayan Sivasankaran, El-Sayed M. Sherif, Fahad A. Almufadi and Abdel-baset H. Mekky

Materials 2023, 16(7), 2891; https://doi.org/10.3390/ma16072891 - 05 Apr 2023

Viewed by 1014

Abstract

In this study, AA5083–WC composites were developed by ball milling followed by hot consolidation. The microstructures of the developed composites were investigated using XRD, SEM, EDX, and EBSD. The developed composites exhibited a homogeneous dispersion of WC particulates in the AA5083 matrix without [...] Read more.

In this study, AA5083–WC composites were developed by ball milling followed by hot consolidation. The microstructures of the developed composites were investigated using XRD, SEM, EDX, and EBSD. The developed composites exhibited a homogeneous dispersion of WC particulates in the AA5083 matrix without any interactions at the matrix/reinforcement interface. The results confirmed the development of a refined equiaxed grain structure of AA5083–WC composites where the EBSD results revealed an average grain size of 4.38 µm and 3.32 µm for AA5083–6%WC (AW-6) and AA5083–12%WC (AW-12) composites, respectively. The results showed that incorporating WC particulates in the AA5083 alloy matrix significantly improved the compressive stress–strain behaviour and considerably enhanced the resistance to wear and friction. The AA5083–12%WC (AW-12) composite displayed the maximum strength and the highest resistance to wear and friction, whereas the as-milled AA5083 alloy (AW-0) exhibited the lowest strength and the least resistance to wear and friction. The AA5083–12%WC (AW-12) composite exhibited the optimum mechanical and tribological behaviour of the developed composites, making it a promising candidate for tribological applications. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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18 pages, 7933 KiB

Open AccessArticle

The Microstructure and Properties of Ni-Si-La₂O₃ Coatings Deposited on 304 Stainless Steel by Microwave Cladding

by Shashi Prakash Dwivedi, Shubham Sharma, Kanta Prasad Sharma, Abhinav Kumar, Ashish Agrawal, Rajesh Singh and Sayed M. Eldin

Materials 2023, 16(6), 2209; https://doi.org/10.3390/ma16062209 - 09 Mar 2023

Cited by 7 | Viewed by 1363

Abstract

In this investigation, microwave radiation was used alongside a combination of Ni powder, Si powder, and La₂O₃ (Lanthanum oxide) powder to create surface cladding on SS-304 steel. To complete the microwave cladding process, 900 W at 2.45 GHz was used [...] Read more.

In this investigation, microwave radiation was used alongside a combination of Ni powder, Si powder, and La₂O₃ (Lanthanum oxide) powder to create surface cladding on SS-304 steel. To complete the microwave cladding process, 900 W at 2.45 GHz was used for 120 s. “Response surface methodology (RSM)” was utilized to attain the optimal combination of microwave cladding process parameters. The surface hardness of the cladding samples was taken as a response. The optimal combination of microwave cladding process parameters was found to be Si (wt.%) of 19.28, a skin depth of 4.57 µm, irradiation time of 118 s, and La₂O₃ (wt.%) of 11 to achieve a surface hardness of 287.25 HV. Experimental surface hardness at the corresponding microwave-cladding-process parameters was found to be 279 HV. The hardness of SS-304 was improved by about 32.85% at the optimum combination of microwave cladding process parameters. The SEM and optical microscopic images showed the presence of Si, Ni, and La₂O₃ particles. SEM images of the “cladding layer and surface” showed the “uniform cladding layer” with “fewer dark pixels” (yielding higher homogeneity). Higher homogeneity reduced the dimensional deviation in the developed cladding surface. XRD of the cladded surface showed the presence of FeNi, Ni₂Si, FeNi₃, NiSi₂, Ni₃C, NiC, and La₂O₃ phases. The “wear rate and coefficient of friction” of the developed cladded surface with 69.72% Ni, 19.28% Si, and 11% La₂O₃ particles were found to be 0.00367 mm³/m and 0.312, respectively. “Few dark spots” were observed on the “corroded surface”. These “dark spots” displayed “some corrosion (corrosion weight loss 0.49 mg)” in a “3.5 wt.% NaCl environment”. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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14 pages, 3186 KiB

Open AccessArticle

Developing Improved Corrosion-Resistant AA5083—BN/WC Composites for Tribological Applications

by Hany R. Ammar, Elsayed M. Sherif, Subbarayan Sivasankaran, Fahad A. Almufadi and Abdel-baset H. Mekky

Materials 2023, 16(4), 1663; https://doi.org/10.3390/ma16041663 - 16 Feb 2023

Cited by 1 | Viewed by 1056

Abstract

In this study, corrosion-resistant AA5083—BN/WC composites were developed for tribological applications through adequate control of the reinforcement content (WC and BN) in the matrix (AA5083 alloy). The effects of 6% and 12% tungsten carbide (WC) as well as 6% and 12% boron nitride [...] Read more.

In this study, corrosion-resistant AA5083—BN/WC composites were developed for tribological applications through adequate control of the reinforcement content (WC and BN) in the matrix (AA5083 alloy). The effects of 6% and 12% tungsten carbide (WC) as well as 6% and 12% boron nitride (BN) additions on the corrosion behavior of AA5083 aluminum composite in 3.5% NaCl solution were carried out. Electrochemical techniques such as cyclic potentiodynamic polarization (CPP), changes in the chronoamperometric current with time (CCT), and electrochemical impedance spectroscopy (EIS) were utilized. The polarization results showed that the addition of 6% WC to the AA5083 alloy matrix improved its resistance to corrosion (R_P). Rp exhibited an additional increase by adding 12% WC to the matrix. The values of R_P were observed to increase for the AA5083 composite when adding 6% BN, and the highest R_P values were recorded for the composite that contains 12% BN. The results obtained by the CPP method were confirmed by CCT and EIS measurements, where the presence of WC and BN protected the developed AA5083- BN/WC composites against corrosion. The corrosion resistance revealed an additional improvement with an increase in WC and BN content from 6% to 12%. The results also confirm that pitting corrosion decreased in the presence of WC and BN in the fabricated composites. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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19 pages, 7258 KiB

Open AccessEditor’s ChoiceArticle

Reinforcement Corrosion Testing in Concrete and Fiber Reinforced Concrete Specimens Exposed to Aggressive External Factors

by Wioletta Raczkiewicz, Magdalena Bacharz, Kamil Bacharz and Michał Teodorczyk

Materials 2023, 16(3), 1174; https://doi.org/10.3390/ma16031174 - 30 Jan 2023

Cited by 4 | Viewed by 1940

Abstract

One of the leading causes of reinforced concrete degradation is chloride attack. It occurs due to the penetration of chlorides through pores and cracks into the concrete cover. This phenomenon becomes more dangerous if reinforced concrete elements are subjected to cyclic temperature changes. [...] Read more.

One of the leading causes of reinforced concrete degradation is chloride attack. It occurs due to the penetration of chlorides through pores and cracks into the concrete cover. This phenomenon becomes more dangerous if reinforced concrete elements are subjected to cyclic temperature changes. The concrete cover protects against corrosion. This paper presents research, the primary purpose of which was to determine the effect of the addition of steel fibers to concrete on the development of corrosion of the main reinforcement. The tests were carried out on three types of reinforced concrete specimens made of ordinary concrete and concrete with different amounts of steel fibers (0.25% and 0.50%). In order to initiate corrosion processes, specimens were partially submerged in a 3% sodium chloride solution and were subjected to freeze–thaw cycles. The electrochemical polarization galvanostatic pulse method was used for analyzing the reinforcement corrosion activity. Moreover, it was verified whether the corrosion of reinforced concrete elements affects the acoustic emission wave velocity. The addition of steel micro-reinforcement fibers increases the corrosion resistance of reinforced concrete. In addition, a strong linear correlation between the AE wave velocity and the values of the corrosion current density was revealed. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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14 pages, 9683 KiB

Open AccessArticle

Effect of Laser Peening on the Corrosion Properties of 304L Stainless Steel

by Young-Ran Yoo, Seung-Heon Choi and Young-Sik Kim

Materials 2023, 16(2), 804; https://doi.org/10.3390/ma16020804 - 13 Jan 2023

Cited by 7 | Viewed by 1161

Abstract

Dry canisters used in nuclear power plants can be subject to localized corrosion, including stress corrosion cracking. External and residual tensile stress can facilitate the occurrence of stress corrosion cracking. Residual stress can arise from welding and plastic deformation. Mitigation methods of residual [...] Read more.

Dry canisters used in nuclear power plants can be subject to localized corrosion, including stress corrosion cracking. External and residual tensile stress can facilitate the occurrence of stress corrosion cracking. Residual stress can arise from welding and plastic deformation. Mitigation methods of residual stress depend upon the energy used and include laser peening, ultrasonic peening, ultrasonic nanocrystal surface modification, shot peening, or water jet peening. Among these, laser peening technology irradiates a continuous laser beam on the surface of metals and alloys at short intervals to add compressive residual stress as a shock wave is caused. This research studied the effect of laser peening with/without a thin aluminum layer on the corrosion properties of welded 304L stainless steel. The intergranular corrosion rate of the laser-peened specimen was a little faster than the rate of the non-peened specimen. However, laser peening enhanced the polarization properties of the cross-section of 304L stainless steel, while the properties of the surface were reduced by laser peening. This behavior was discussed on the basis of the microstructure and residual stress. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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11 pages, 5745 KiB

Open AccessArticle

Duplex Coating Combing Vanadate-Intercalated Layered Double Hydroxide and Ce-Doped Sol–Gel Layers on Aluminum Alloy for Active Corrosion Protection

by Kai Wei, Xuejie Zhao, Zhe Zhang, Yujie Yuan, Wenquan Kong and You Zhang

Materials 2023, 16(2), 775; https://doi.org/10.3390/ma16020775 - 12 Jan 2023

Cited by 3 | Viewed by 1415

Abstract

In this study, a duplex coating system (LDH-V/SG-Ce) of vanadate-intercalated layered double hydroxide (LDH) and Ce-doped sol–gel (SG) layers was developed for the purpose of active corrosion protection of the aluminum alloy AA2024. ZnAl-LDH film was grown in situ on the surface of [...] Read more.

In this study, a duplex coating system (LDH-V/SG-Ce) of vanadate-intercalated layered double hydroxide (LDH) and Ce-doped sol–gel (SG) layers was developed for the purpose of active corrosion protection of the aluminum alloy AA2024. ZnAl-LDH film was grown in situ on the surface of an aluminum alloy using a hydrothermal method and intercalated with V₂O₇⁴⁻ anions as corrosion inhibitors, and sealed with a Ce (III)-doped silane coating using a sol–gel technique. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses were used to analyze the microstructure, surface functional groups and structure of the LDH-V/SG-Ce film. The uniform and compact silane layer was covered both in the pores and on top of the LDH film. The results of glow discharge optical emission spectroscopy (GDOES) indicated that V₂O₇⁴⁻ and Ce (III) ions were loaded in the LDH layer and silane film, respectively. The potentiodynamic polarization results showed that the corrosion current density of the bilayer system in the presence of corrosion inhibitors was reduced to 1.92 × 10⁻⁸ A/cm². Electrochemical impedance spectroscopy (EIS) results showed that the LDH-V/SG-Ce duplex coating could provide effective protection for the aluminum alloy after being exposed to a corrosive solution for 14 days. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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15 pages, 17215 KiB

Open AccessArticle

Solidification Cracking Restraining Mechanism of Al-Cu-Mg-Zn Alloy Welds Using Cold Metal Transfer Technique

by Zhuoxin Li, Lingshan Ou, Yipeng Wang, Hong Li, Mariusz Bober, Jacek Senkara and Yu Zhang

Materials 2023, 16(2), 721; https://doi.org/10.3390/ma16020721 - 11 Jan 2023

Cited by 3 | Viewed by 1137

Abstract

Aluminum alloy 7075 (with 7055 and 7150 filler wires) was welded using a digital welding machine that can switch arc mode between MIG, CMT and CMT+P modes. The transverse-motion weldability test of joints welded under different arc modes showed that the solidification cracking [...] Read more.

Aluminum alloy 7075 (with 7055 and 7150 filler wires) was welded using a digital welding machine that can switch arc mode between MIG, CMT and CMT+P modes. The transverse-motion weldability test of joints welded under different arc modes showed that the solidification cracking susceptibility was lower in CMT-technique-based welds than in MIG welds. The temperature cycle of the welding pool under different arc modes was recorded using mini-thermocouples, which showed that the cooling rate was lower in CMT welded samples than in MIG welded samples. The low cooling rate promoted the growth of α-Al dendrites through the back diffusion effect. Electron probe micro-analysis showed that micro-segregation of the α-Al dendrites was lower in the CMT welded samples than in the MIG welded samples. The T-(f_Al)^1/2 curve of each weld was calculated, which showed that CMT-based welding enhanced the bridging of adjacent α-Al dendrites, reducing the tendency for solidification cracking. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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15 pages, 6339 KiB

Open AccessArticle

Influence of Long-Period Stacked Ordered Phases on Inductive Impedance of Mg-Gd-Y-Zn-Zr-Ag Alloys

by Shiyuan Xu, Chuming Liu, Yonghao Gao, Shunong Jiang, Yingchun Wan and Zhiyong Chen

Materials 2023, 16(2), 640; https://doi.org/10.3390/ma16020640 - 09 Jan 2023

Cited by 1 | Viewed by 1000

Abstract

In this paper, the influence of long-period stacked ordered (LPSO) phases on the electrochemical impedance spectroscopy (EIS) of a Mg-Gd-Y-Zn-Zr-Ag alloy in 0.9 wt.% NaCl was investigated. The Mg-6Gd-3Y-1Zn-0.5Zr-0.3Ag (wt.%) alloy samples with and without LPSO phases in the grain interior (HOMO and [...] Read more.

In this paper, the influence of long-period stacked ordered (LPSO) phases on the electrochemical impedance spectroscopy (EIS) of a Mg-Gd-Y-Zn-Zr-Ag alloy in 0.9 wt.% NaCl was investigated. The Mg-6Gd-3Y-1Zn-0.5Zr-0.3Ag (wt.%) alloy samples with and without LPSO phases in the grain interior (HOMO and LPSO, respectively) were prepared using different heat treatments. The EIS results showed that both the HOMO and LPSO samples’ Nyquist diagrams contained two inductive loops. However, in the Nyquist plots of the LPSO samples, the inductive loops at 1.71–0.67 Hz appeared in the first quadrant rather than the fourth quadrant. Analysis of the fitting parameters illustrated that the abnormal shape of the inductive loops is related to greater values of the surface film capacitance C_f and double layer capacitance C_dl in the LPSO samples. Further investigations through corrosion morphology observation indicated that the greater values of C_f and C_dl in the LPSO samples resulted from the existence of intragranular LPSO phases that created more film-free areas. The above results show that a better understanding of the relationship between the inductive impedance and corrosion morphology of a Mg-6Gd-3Y-1Zn-0.5Zr-0.3Ag alloy in 0.9 wt.% NaCl solution was attained. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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14 pages, 5317 KiB

Open AccessArticle

Electrochemical and Mechanical Properties of Cathodically Protected X80 Steel in Different Temperature Soil

by Wenhui Liu, Yanbing Meng, Jun Zhao, Wen Wen, Ming Gong, Shixiong Wu, Songmei Li, Mei Yu and Jianhua Liu

Materials 2022, 15(16), 5526; https://doi.org/10.3390/ma15165526 - 11 Aug 2022

Cited by 2 | Viewed by 1155

Abstract

For the application of X80 pipelines in Northeast China, it is important to establish the correct cathodic protection (CP) potential. To achieve this, potentiodynamic polarization; electrochemical impedance spectroscopy (EIS); a slow strain rate test (SSRT); and a scanning electron microscopy (SEM) fracture morphology [...] Read more.

For the application of X80 pipelines in Northeast China, it is important to establish the correct cathodic protection (CP) potential. To achieve this, potentiodynamic polarization; electrochemical impedance spectroscopy (EIS); a slow strain rate test (SSRT); and a scanning electron microscopy (SEM) fracture morphology analysis were carried out for an X80 steel gas pipeline at several temperatures in Heilongjiang Province, China. The results show that the hydrogen evolution potential of X80 steel in soil at different temperatures was about −900 mV (vs. CSE). The generated hydrogen atoms can be adsorbed on the surface of the pipelines to reduce the surface energy, or they can be diffused into the substrate and accumulate to the critical concentration, inducing the decohesion between different structures and generating additional plastic deformation through dislocation motion. With the peak impedance potential as the minimum potential and the hydrogen embrittlement potential as the maximum potential, the CP potential of X80 steel in the soil at 30 °C, 45 °C, and 60 °C ranged from −900 mV to −1100 mV (vs. CSE), temperatures at which the X80 steel does not corrode or cause hydrogen embrittlement. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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14 pages, 7399 KiB

Open AccessArticle

Effect of Laser Peening on Microstructural Changes in GTA-Welded 304L Stainless Steel

by Young-Ran Yoo, Jae-Sung Kim and Young-Sik Kim

Materials 2022, 15(11), 3947; https://doi.org/10.3390/ma15113947 - 01 Jun 2022

Cited by 2 | Viewed by 1297

Abstract

The introduction of tensile residual stress has led to the induction of damage such as fatigue, corrosion fatigue, and stress corrosion cracking (SCC) in stainless steel in association with the influence of environments, components, surface defects, and corrosive factors during its use. Compressive [...] Read more.

The introduction of tensile residual stress has led to the induction of damage such as fatigue, corrosion fatigue, and stress corrosion cracking (SCC) in stainless steel in association with the influence of environments, components, surface defects, and corrosive factors during its use. Compressive residual stress can be achieved through various techniques. Among several methods, laser peening can be more attractive as it creates regularity on the surface with a high-quality surface finish. However, there is very little research on heavily peened surface and cross-section of stainless steel with very deep compressive residual stress. This work focused on welding and laser peening and the influence of Al coating on the microstructural changes in 304L stainless steel. The specimen obtained by laser peening had a very deep compressive residual stress of over 1 mm and was evaluated based on microstructural and hardness analysis. Therefore, a model for microstructural change by laser peening on welded 304L stainless steel was proposed. Full article

(This article belongs to the Special Issue Corrosion of Materials: Evaluation, Testing, Protection, and Failure Analysis)

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