Understanding the low corrosion potential and high corrosion resistance of nano-zinc electrodeposit based on electron work function and interfacial potential difference

RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 97606-97612 ◽  
Author(s):  
Qingyang Li ◽  
Hao Lu ◽  
Juan Cui ◽  
Maozhong An ◽  
Dongyang (D. Y.) Li
Keyword(s):  
Corrosion Resistance ◽  
Work Function ◽  
Corrosion Potential ◽  
Electron Work Function ◽  
Coarse Grained ◽  
High Corrosion Resistance ◽  
Corrosion Behaviors ◽  
Interfacial Potential ◽  
Nano Zinc ◽  
Zinc Coatings

The corrosion behaviors of coarse-grained and nanocrystalline zinc coatings and correlated the corrosion potential with electron stability are investigated.

Influences of Grain Size on Electrochemical Corrosion Behaviors of Nickel-Based Alloy 718

2016 ◽  
Vol 852 ◽  
pp. 105-112 ◽  
Author(s):  
Yan Mo ◽  
Dong Zhe Wang ◽  
Bin Jiang ◽  
Yong You Li ◽  
Hai Ding Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Sea Water ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Structure Design ◽  
Coarse Grained ◽  
Alloy 718 ◽  
Corrosion Behaviors ◽  
Nickel Based Alloy

With the application upgrade of alloy 718 in the marine oil exploitation, higher corrosion resistance demands has been presented for structure design and reasonable material application of drilling and production equipments; thus there is an urgent need to understand influences of grain size on corrosion behavior of such alloy in sea water environment. In this experiment, different solution treatments are applied to nickel-based alloy 718. As a result, specimens with grain size varied from ASTM No. 9 to No. 3.5 grades. The influences of grain size on the electrochemical behaviors in simulated sea water (3.5% sodium chloride solution) are investigated using electrochemical impedance spectroscopy and polarization curves. Alloy 718 shows good corrosion resistance in this electrolyte solution, however, grain size still has an effect on its electrochemical corrosion behaviors to a certain extent. With the time going, testing results show that coarse-grained alloys with larger grain size have higher impedance values and smaller corrosion current densities, indicating a better corrosion resistance than fine-grained specimens. However, when the grain size increases further, the corrosivity resistant nature of alloy 718 would decline. Testing results show that specimen with size of ASTM No. 5 has the best corrosion resistance.

HIGH CORROSION RESISTANCE OF NI-P/NANO-SIO2 ELECTROLESS COMPOSITE COATINGS

2012 ◽  
Vol 05 ◽  
pp. 810-816 ◽  
Author(s):  
S.R. Allahkaram ◽  
T. Rabizadeh
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Carbon Steels ◽  
Nano Particles ◽  
Chemical Compositions ◽  
High Corrosion Resistance ◽  
Coating Type ◽  
Corrosion Behaviors ◽  
Electroless Ni

The process of electroless plating Ni - P and Ni - P /nano- SiO 2 on API-5L X65 carbon steels was improved. The Ni - P /nano- SiO 2 composite coatings were prepared from the bathes containing different concentrations of nano- SiO 2 particles. The coatings surface and morphologies were observed via scanning electron microscopy (SEM). The chemical compositions were analyzed by EDAX. The corrosion behaviors were evaluated by electrochemical impedance spectroscopy tests. The experimental results indicated that SiO 2 nano-particles co-deposited but some agglomeration occurred. Micro-hardness of electroless Ni - P - SiO 2 composite coatings increased due to the existence of nano-particles. Corrosion tests showed that both electroless Ni - P and Ni - P /nano- SiO 2 composite coatings demonstrated significant improvement of corrosion resistance of substrate in salty atmosphere and latter coating type appeared to offer a better corrosion protection.

scholarly journals Effect of Ca Content on the Mechanical Properties and Corrosion Behaviors of Extruded Mg–7Li–3Al Alloys

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1212
Author(s):  
Xiong ◽  
Yang ◽  
Deng ◽  
Li ◽  
Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Ca Addition ◽  
Corrosion Behaviors ◽  
Superior Corrosion Resistance ◽  
Mechanical Properties And Corrosion

The effect of Ca addition on the microstructure, mechanical properties, and corrosion behaviors of the extruded Mg–7Li–3Al alloys was investigated. The results showed that the extruded Mg–7Li–3Al–xCa alloys consisted of α-Mg (hcp) + β-Li (bcc) matrix phases and Al2Ca. With increasing Ca content, the amount and morphology of the Al2Ca phase changed significantly. The grains of the extruded Mg–7Li–3Al–xCa alloys were refined by dynamic recrystallization during the extrusion process. The tensile tests results indicated that the extruded Mg–7Li–3Al–0.4Ca alloy exhibited favorable comprehensive mechanical properties; its ultimate tensile strength was 286 MPa, the yield strength was 249 MPa, and the elongation was 18.7%. The corrosion results showed that this alloy with 0.4 wt.% Ca addition exhibited superior corrosion resistance, with a corrosion potential Ecorr of −1.48742 VVSE, attributed to the formation of protective Al2Ca phases.

scholarly journals Investigation of the effect of benzothiazinesulfonamide derivatives as inhibitors of microbiological corrosion of steel with composite zinc/biocide coating

2019 ◽  
Vol 121 ◽  
pp. 02001
Author(s):  
Angela Gribankova ◽  
Maria Agievich ◽  
Xiaofan Zhai ◽  
Jizhou Duan ◽  
Baorong Hou
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Process ◽  
Microbiological Corrosion ◽  
High Corrosion Resistance ◽  
Zinc Electrodeposition ◽  
Zinc Plating ◽  
Metallurgical Analysis ◽  
Lattice Surface ◽  
Zinc Coatings ◽  
Corrosion Of Steel

This study evaluated the biocidal and electrochemical inhibitory effectiveness of the organic compound (OC) 1,2,3,4,4a, 10b-hexahydro-1,4-methano-6H-dibenzo [c, e] -5,6-thiazine-5,5-dioxide when introduced into a zinc-plating electrolyte. Structural and metallurgical analysis of the resultant coatings was carried out using XRD and SEM techniques. During zinc electrodeposition, OC molecules were adsorbed on the surface of the zinc coatings. In a corrosive medium, destruction of molecules in the crystal lattice surface stopped the sulphate-reducing bacterial metabolic chain and retarded the corrosion process. The coatings exhibited high corrosion-resistance and good physical characteristics.

An abnormal correlation between electron work function and corrosion resistance in Ti-Zr-Be-(Ni/Fe) metallic glasses

2020 ◽  
Vol 165 ◽  
pp. 108392 ◽  
Author(s):  
Jia-Lun Gu ◽  
Yang Shao ◽  
Heng-Tong Bu ◽  
Ji-Li Jia ◽  
Ke-Fu Yao
Keyword(s):  
Corrosion Resistance ◽  
Work Function ◽  
Metallic Glasses ◽  
Electron Work Function

Electron work function at grain boundary and the corrosion behavior of nanocrystalline metallic materials

2005 ◽  
Vol 887 ◽  
Author(s):  
D. Y. Li
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Work Function ◽  
Nanocrystalline Materials ◽  
Minimum Energy ◽  
Electron Work Function ◽  
Chemical Properties ◽  
Nanocrystalline Structure ◽  
Boundary Density

ABSTRACTDue to their high grain boundary density, nanocrystalline materials possess unusual mechanical, physical and chemical properties. Extensive research on nanocrystalline materials has been conducted in recent years. Many studies have shown that corrosion, one of important properties of nanocrystalline materials, is crucial to their applications. In this article, the activity of electrons at grain boundaries of metallic surfaces is analyzed based the electron work function (EWF), the minimum energy required to attract electrons from inside a metal. It is demonstrated that at grain boundaries, the electron work function decreases, indicating that at a grain boundary, electrons are more active. As a result, the surface becomes more electrochemically reactive. Such increase in electrochemical reactivity has negative effect on the corrosion resistance of nanocrystalline materials. However, for a passive nanocrystalline metal or alloy, the nanocrystalline structure is beneficial to its corrosion resistance through rapid formation of a protective passive film. The mechanisms responsible for the variation in EWF at grain boundary and effects of nanocrystallization on corrosion are discussed in this article.

scholarly journals Effect of Sc and Zr Additions on Recrystallization Behavior and Intergranular Corrosion Resistance of Al-Zn-Mg-Cu Alloys

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5516
Author(s):  
Peng Xia ◽  
Shuncheng Wang ◽  
Huilan Huang ◽  
Nan Zhou ◽  
Dongfu Song ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Intergranular Corrosion ◽  
Sharp Decrease ◽  
Electrochemical Process ◽  
Recrystallization Behavior ◽  
High Corrosion Resistance ◽  
Cu Alloys ◽  
Low Degree ◽  
Corrosion Behaviors ◽  
Zr Alloy

The recrystallization and intergranular corrosion behaviors impacted by the additions of Sc and Zr in Al-Zn-Mg-Cu alloys are investigated. The stronger effect of coherent Al3(Sc1−xZrx) phases on pinning dislocation resulted in a lower degree of recrystallization in Al-Zn-Mg-Cu-Sc-Zr alloy, while the subgrain boundaries can escape from the pinning of Al3Zr phases and merge with each other, bringing about a higher degree of recrystallization in Al-Zn-Mg-Cu-Zr alloy. A low degree of recrystallization promotes the precipitation of grain boundary precipitates (GBPs) with a discontinuous distribution, contributing to the high corrosion resistance of Al-Zn-Mg-Cu-Sc-Zr alloy in the central layer. The primary Al3(Sc1−xZrx) phase promotes recrystallization due to particle-stimulated nucleation (PSN), and acts as the cathode to stimulate an accelerated electrochemical process between the primary Al3(Sc1−xZrx) particles and GBPs, resulting in a sharp decrease of the corrosion resistance in the surface layer of Al-Zn-Mg-Cu-Sc-Zr alloy.

Grain Boundary Modification by Si3N4 Additions and the Effect on Corrosion Behaviors in Two Sintered Nd-Fe-B Magnets

2010 ◽  
Vol 89-91 ◽  
pp. 733-738
Author(s):  
Qiong Zhen Liu ◽  
Lan Ting Zhang ◽  
Ai Dang Shan ◽  
Jian Sheng Wu ◽  
Matahiro Komuro
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Oxygen Content ◽  
Corrosion Potential ◽  
Low Oxygen ◽  
High Oxygen Content ◽  
Intergranular Phase ◽  
Microstructure Observation ◽  
Corrosion Behaviors ◽  
Boundary Modification

Two sintered magnets Nd15Dy1.2Fe77Al0.8B6 and Nd22Fe71B7 were modified by intergranular additions of Si3N4. The remanence as well as sintering density of the two magnets increased slightly with appropriate amount of Si3N4 additives. Meanwhile, there was an obvious increase in coercivity of the Nd-rich Nd22Fe71B7 magnet after 0.3 wt. % Si3N4 was added to magnets. Besides the effects on magnetic properties, an improved corrosion resistance was observed. Compared with the native magnets without any additions, corrosion potential of the magnets with Si3N4 additives is more positive and the current density in the anodic branch of the polarization curve is reduced. Microstructure observation reveals that Si3N4 additives have been incorporated into the intergranular phases in the magnets. Si is found to enrich in the Nd-rich intergranular phase with low oxygen content. With the introduction of Si3N4 additives, more intergranular phase with high oxygen content is formed, which may contribute to improved corrosion resistance. In addition, addition of Si3N4 refines the grain size of Nd22Fe71B7.

Effect of Phosphating Additives on Corrosion Resistance of Phosphate Coatings on AZ91D Magnesium Alloy

2011 ◽  
Vol 337 ◽  
pp. 112-115 ◽  
Author(s):  
Bi Lan Lin ◽  
Yu Ye Xu ◽  
En Cai Li
Keyword(s):  
Corrosion Resistance ◽  
Sodium Fluoride ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Zinc Nitrate ◽  
Open Circuit ◽  
Nacl Solution ◽  
Tafel Polarization ◽  
Phosphate Coatings ◽  
Corrosion Behaviors

AZ91D magnesium alloys were immersed in different phosphating solutions with zinc nitrate and sodium fluoride additives to enhance the corrosion resistance. The devolution law of the Open Circuit Potential (OCP) of AZ91D alloys during phosphating was measured. The corrosion behaviors of AZ91D alloys in 3.5%NaCl solution were investigated using OCP and Tafel polarization methods, and the effect of phosphating additives was discussed. The results show that the changes of the OCP of AZ91D alloys with phosphating time in different phosphating solutions are different; the anodic and cathodic corrosion processes of AZ91D alloys are conspicuously inhibited with phosphate coatings; zinc nitrate and sodium fluoride are benefit to form phosphate coatings with better corrosion resistance. The corrosion potential of AZ91D alloy phosphated in solutions with both zinc nitrate and sodium fluoride is most positive.

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