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Shen C, Zhu Z. Electrochemical dissolution behavior of Narloy-Z in sulfuric acid and sulfamic acid solutions. J APPL ELECTROCHEM 2022. [DOI: 10.1007/s10800-022-01777-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Zakerin N, Morshed-Behbahani K. Perspective on the passivity of Ti6Al4V alloy in H2SO4 and NaOH solutions. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115947] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Corrosion Behavior of As-Cast Ti–10Mo–6Zr–4Sn–3Nb and Ti–6Al–4V in Hank’s Solution: A Comparison Investigation. METALS 2020. [DOI: 10.3390/met11010011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Newly developed Ti–10Mo–6Zr–4Sn–3Nb has fascinating mechanical properties to be used as a biomedical material. However, there is still a lack of investigation focusing on the corrosion behavior of Ti–10Mo–6Zr–4Sn–3Nb. In this work, the microstructure and corrosion behavior of as-cast Ti–10Mo–6Zr–4Sn–3Nb was investigated by optical microscopy, X-ray diffraction, and electrochemical measurements. Hank’s solution was used as the electrolyte. A classical as-cast Ti–6Al–4V was used as reference. The results showed that Ti–10Mo–6Zr–4Sn–3Nb has a higher corrosion potential and a lower corrosion current density compared with Ti–6Al–4V, indicating better corrosion resistance. However, after applying anodic potentials, Ti–10Mo–6Zr–4Sn–3Nb shows larger passivation current density in both potentiodynamic polarization and potentiostatic polarization tests. This is because more alloying elements contained in Ti–10Mo–6Zr–4Sn–3Nb trigger the production of a larger number of oxygen vacancies, resulting in a higher flux of oxygen vacancy. This finding illustrates that the passive film on Ti–10Mo–6Zr–4Sn–3Nb is less protective compared with that on Ti–6Al–4V when applying an anodic potential in their passivation range.
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Tian W, Li Z, Kang H, Cheng F, Chen F, Pang G. Passive Film Properties of Bimodal Grain Size AA7075 Aluminium Alloy Prepared by Spark Plasma Sintering. MATERIALS 2020; 13:ma13143236. [PMID: 32708110 PMCID: PMC7412012 DOI: 10.3390/ma13143236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/17/2020] [Accepted: 07/17/2020] [Indexed: 11/16/2022]
Abstract
The bimodal-grain-size 7075 aluminium alloys containing varied ratios of large and small 7075 aluminium powders were prepared by spark plasma sintering (SPS). The large powder was 100 ± 15 μm in diameter and the small one was 10 ± 5 μm in diameter. The 7075 aluminium alloys was completely densified under the 500 °C sintering temperature and 60 MPa pressure. The large powders constituted coarse grain zone, and the small powders constituted fine grain zone in sintered 7075 aluminium alloys. The microstructural and microchemical difference between the large and small powders was remained in coarse and fine grain zones in bulk alloys after SPS sintering, which allowed for us to investigate the effects of microstructure and microchemistry on passive properties of oxide film formed on sintered alloys. The average diameter of intermetallic phases was 201.3 nm in coarse grain zone, while its vale was 79.8 nm in fine grain zone. The alloying element content in intermetallic phases in coarse grain zone was 33% to 48% higher than that on fine grain zone. The alloying element depletion zone surrounding intermetallic phases in coarse grain zone showed a bigger width and a more severe element depletion. The coarse grain zone in alloys showed a bigger electrochemical heterogeneity as compared to fine grain zone. The passive film formed on coarse grain zone had a thicker thickness and a point defect density of 2.4 × 1024 m−3, and the film on fine grain zone had a thinner thickness and a point defect density of 4.0 × 1023 m−3. The film resistance was 3.25 × 105 Ωcm2 on coarse grain zone, while it was 6.46 × 105 Ωcm2 on fine grain zone. The passive potential range of sintered alloys increased from 457 mV to 678 mV, while the corrosion current density decreased from 8.59 × 10−7 A/cm2 to 6.78 × 10−7 A/cm2 as fine grain zone increasing from 0% to 100%, which implied that the corrosion resistance of alloys increased with the increasing content of fine grains. The passive film on coarse grain zone exhibited bigger corrosion cavities after pitting initiation compared to that on fine grain zone. The passive film formed on fine grain zone showed a better corrosion resistance. The protectiveness of passive film was mainly determined by defect density rather than the thickness in this work.
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Affiliation(s)
- Wenming Tian
- School of Materials Engineering, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China; (Z.L.); (H.K.); (F.C.); (G.P.)
- Heibei Key Laboratory of Trans-Media Aerial Underwater Vehicle, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China
- Correspondence: ; Tel.: +86-181-3169-1636
| | - Zhonglei Li
- School of Materials Engineering, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China; (Z.L.); (H.K.); (F.C.); (G.P.)
- Heibei Key Laboratory of Trans-Media Aerial Underwater Vehicle, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China
| | - HuiFeng Kang
- School of Materials Engineering, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China; (Z.L.); (H.K.); (F.C.); (G.P.)
- Heibei Key Laboratory of Trans-Media Aerial Underwater Vehicle, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China
| | - Fasong Cheng
- Aero Engine Corporation of China (AECC) Guizhou Liyang Aviation Power CO., LTD., Guiyang 550014, China;
| | - Fangfang Chen
- School of Materials Engineering, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China; (Z.L.); (H.K.); (F.C.); (G.P.)
| | - Guoxing Pang
- School of Materials Engineering, North China Institute of Aerospace Engineering, No.133 Aimindong Road, Langfang 065000, China; (Z.L.); (H.K.); (F.C.); (G.P.)
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Zha L, Li H, Wang N. In Situ Electrochemical Study of the Growth Kinetics of Passive Film on TC11 Alloy in Sulfate Solution at 300 °C/10 MPa. MATERIALS 2020; 13:ma13051135. [PMID: 32143341 PMCID: PMC7084967 DOI: 10.3390/ma13051135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/04/2022]
Abstract
TC11 alloy is a promising structural material, and has a wide range of applications in many corrosive and high temperature hydrothermal systems. The passive film has an important influence on its electrochemical behavior. In this study, in-situ electrochemical methods (that is, open circuit potential (OCP), linear polarization (LP) and electrochemical impedance spectroscopy (EIS)) were used to monitor the long period electrochemical behavior of TC11 alloy in 0.01 M Na2SO4 solution at 300 °C/10 MPa. The growth kinetics of the passive film was mainly studied. The correlation between the evolution of the electrochemical behavior and the growth of the oxide film was discussed. The results showed that although the OCP gradually stabilized after twenty thousand seconds, henceforth the polarization resistance (Rp) was still increasing due to the thickening of the passive film. An equivalent circuit was proposed to fit the EIS experimental data, leading to determination of film capacitance and film resistance. Besides, the electrochemical data was interpreted in terms of the point defect model (PDM). The EIS results are consistent with the Rp results.
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Affiliation(s)
- Lei Zha
- College of Chemistry and Materials Engineering, Guiyang University, Guiyang 550005, China;
| | - Heping Li
- Key Laboratory of High-temperature and High-pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Correspondence:
| | - Ning Wang
- Key Laboratory of High-temperature and High-pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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