Corrosion mechanism of nanocrystalline Zn–Ni alloys obtained from a new DMH-based bath as a replacement for Zn and Cd coatings

RSC Advances ◽  
2016 ◽  
Vol 6 (69) ◽  
pp. 64726-64740 ◽  
Author(s):  
Zhongbao Feng ◽  
Maozhong An ◽  
Lili Ren ◽  
Jinqiu Zhang ◽  
Peixia Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Mechanism ◽  
Ni Alloys

Nanocrystalline Zn–Ni alloys obtained from a DMH-based bath can be used as replacement of Zn and Cd coatings. The mechanism of better corrosion resistance of Zn–Ni alloys compared to Zn and Cd coatings was analyzed by XPS and EIS.

Effect of additives on the corrosion mechanism of nanocrystalline zinc–nickel alloys in an alkaline bath

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88469-88485 ◽  
Author(s):  
Zhongbao Feng ◽  
Lili Ren ◽  
Jinqiu Zhang ◽  
Peixia Yang ◽  
Maozhong An
Keyword(s):  
Corrosion Resistance ◽  
Nickel Alloys ◽  
Corrosion Mechanism ◽  
Ni Alloys ◽  
Effect Of Additives ◽  
Alkaline Bath ◽  
Zinc Nickel

Bright Zn–Ni alloys can be obtained from the bath with additives. The mechanism of better corrosion resistance of bright Zn–Ni alloys compared to dull Zn–Ni alloys was analyzed by XPS and EIS.

Microstructures of Ti-1.5 w/o Ni Alloys with Mo and A1 Additions

1975 ◽  
Vol 33 ◽  
pp. 54-55
Author(s):  
Anna C. Fraker
Keyword(s):  
Corrosion Resistance ◽  
Beneficial Effect ◽  
Crevice Corrosion ◽  
Local Corrosion ◽  
Precipitate Size ◽  
Ni Alloys

Small amounts of nickel are added to titanium to improve the crevice corrosion resistance but this results in an alloy which has sheet fabrication difficulties and is subject to the formation of large Ti2Ni precipitates. These large precipitates can serve as local corrosion sites; but in a smaller more widely dispersed form, they can have a beneficial effect on crevice corrosion resistance. The purpose of the present work is to show that the addition of a small amount of Mo to the Ti-1.5Ni alloy reduces the Ti2Ni precipitate size and produces a more elongated grained microstructure. It has recently been reported that small additions of Mo to Ti-0.8 to lw/o Ni alloys produce good crevice corrosion resistance and improved fabrication properties.

scholarly journals Effect of Oxide Scale Microstructure on Atmospheric Corrosion Behavior of Hot Rolled Steel Strip

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 517
Author(s):  
Bin Sun ◽  
Lei Cheng ◽  
Chong-Yang Du ◽  
Jing-Ke Zhang ◽  
Yong-Quan He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Atmospheric Corrosion ◽  
Corrosion Mechanism ◽  
Type I ◽  
Rust Layer ◽  
Hot Rolled

The atmospheric corrosion behavior of a hot-rolled strip with four types (I–IV) of oxide scale was investigated using the accelerated wet–dry cycle corrosion test. Corrosion resistance and porosity of oxide scale were studied by potentiometric polarization measurements. Characterization of samples after 80 cycles of the wet–dry corrosion test showed that scale comprised wüstite and magnetite had strongest corrosion resistance. Oxide scale composed of inner magnetite/iron (>70%) and an outer magnetite layer had the weakest corrosion resistance. The corrosion kinetics (weight gain) of each type of oxide scale followed an initial linear and then parabolic (at middle to late corrosion) relationship. This could be predicted by a simple kinetic model which showed good agreement with the experimental results. Analysis of the potentiometric polarization curves, obtained from oxide coated steel electrodes, revealed that the type I oxide scale had the highest porosity, and the corrosion mechanism resulted from the joint effects of electrochemical behavior and the porosity of the oxide scale. In the initial stage of corrosion, the corrosion product nucleated and an outer rust layer formed. As the thickness of outer rust layer increased, the corrosion product developed on the scale defects. An inner rust layer then formed in the localized pits as crack growth of the scale. This attacked the scale and expanded into the substrate during the later stage of corrosion. At this stage, the protective effect of the oxide scale was lost.

scholarly journals Investigation of Corrosion Resistance Enhancement for Biodegradable Magnesium Alloy by Ball Burnishing Process

2020 ◽  
Vol 14 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Chenyao Cao ◽  
Jiang Zhu ◽  
Tomohisa Tanaka ◽  
Dinh Ngoc Pham ◽  
◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Mass Loss ◽  
Immersion Test ◽  
Corrosion Products ◽  
Mg Alloys ◽  
Surface Finishing ◽  
Human Organism ◽  
Corrosion Mechanism ◽  
Ball Burnishing ◽  
Treated Sample

Magnesium and magnesium-based alloys are considered ideal materials for implants in orthopedic treatment because their stiffness is close to that of human bones, and they can be absorbed gradually in the human organism. However, a major issue in their actual application is that the corrosion speed of Mg alloys is very high in aggressive environments such as the human fluids. In previous studies, many approaches have been attempted to enhance the corrosion resistance of Mg alloys. In this research, ball burnishing, a mechanical surface finishing process, is applied to improve the corrosion resistance of Mg alloys by changing its surface properties. The influence of the burnishing parameters on the corrosion resistance is investigated, and the corrosion of a treated and non-treated sample are compared. The test material used is the AZ31 Mg alloy. Firstly, a comprehensive review of the effect of burnishing on the final microstructures is reported. The influence of burnishing on grain size, work-hardened layer thickness, crystal orientation, and residual stress of the sample is discussed. Secondly, by conducting an especially designed long-term immersion test, the mass loss and surface evolution of each sample are evaluated. The experimental results indicate that, under proper processing conditions, the mass loss of the treated sample (8.8 mg) can be reduced to 36% of the non-treated one (24.2 mg). To elucidate the mechanism behind corrosion resistance enhancement by burnishing, the samples treated with the optimal processing parameters found are immersed in an aggressive solution for 1, 3, 5, and 7 days. From the results of mass loss measurement and surface structure characterization, it was found that, among pitting, general, and intergranular corrosion, pitting corrosion is the dominant corrosion mechanism. The holes enlarge because pits combine together, representing the greatest portion of mass loss. The main mechanism enhancing corrosion resistance is the size reduction of the grains on the surface induced by ball burnishing, causing a denser distribution of corrosion products in the immersion test. These corrosion products protect the material underneath accelerated corrosion.

Effects of mass ratios on salt spray corrosion and electrochemical corrosion behaviors of laser cladded Cr–Ni coatings

2019 ◽  
Vol 66 (3) ◽  
pp. 352-359
Author(s):  
Li Jiahong ◽  
Kong Dejun
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Salt Spray ◽  
Electrochemical Corrosion ◽  
Corrosion Mechanism ◽  
H13 Steel ◽  
Content Type ◽  
Salt Spray Corrosion ◽  
Electrochemical Tests ◽  
Mass Ratios

Purpose The purpose of this paper is to improve the salt spray corrosion and electrochemical corrosion performances of H13 hot work mould steel, Cr–Ni coatings with the different Cr and Ni mass ratios are fabricated using a laser cladding (LC), which provides an experimental basis for the surface modification treatment of H13 steel. Design/methodology/approach Cr–Ni coatings with the different Cr and Ni mass ratios were firstly fabricated on H13 hot work mould steel using a laser cladding (LC). The salt spray corrosion (SSC) and electrochemical corrosion performances of Cr–Ni coatings in 3.5 Wt.% NaCl solution were investigated to analyze the corrosion mechanism, and the effect of mass ratios of Cr and Ni on their corrosion mechanism was discussed. Findings The laser cladded Cr–Ni coatings with the different Cr and Ni mass ratios are composed of Cr–Ni compounds, which are metallurgically combined with the substrate. The SSC resistance of Cr–Ni coating with the Cr and Ni mass ratios of 24:76 is the highest. The electrochemical corrosion resistance of Cr–Ni coating with the Cr and Ni mass ratio of 24:76 is the best among the three kinds of coatings. Originality/value In this study, the corrosion resistance of laser cladded Cr–Ni coatings with the Cr and Ni mass ratios of 17: 83, 20: 80 and 24: 76 was first evaluated using salt spray corrosion (SSC) and electrochemical tests, and the effect of mass ratios of Cr and Ni on their corrosion mechanism was discussed.

Corrosion of Fe-Cr and Fe-Cr-Ni Alloys at 700-800°C in CO2-0.3SO2-6O2 Mixed Gas

2020 ◽  
Vol 833 ◽  
pp. 85-89
Author(s):  
Min Jung Kim ◽  
Dong Bok Lee ◽  
Xiao Xiao ◽  
Kyong Hwan Lee
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Alloying Elements ◽  
Mixed Gas ◽  
Corrosion Rates ◽  
Ni Alloys

ASTM T22 (Fe-2.25Cr-1Mo), 347HFG (Fe-18Cr-11Ni), and 310H (Fe-25Cr-19Ni) steels were reacted with CO2-0.3SO2-6O2 mixed gas. During corrosion at 700-800 °C for 20-100 h, 347HFG (Fe-18Cr-11Ni), and 310H (Fe-25Cr-19Ni) steels had good protective Cr2O3 oxide scale. Corrosion rates increased progressively as the corrosion temperature and time increased. Corrosion resistance increased in the order of T22, 347HFG, and 310H, suggesting that the alloying elements of Cr and Ni beneficially improved the corrosion resistance of steels. Basically, Fe oxidized to Fe2O3, and Cr oxidized to Cr2O3, some of which further reacted with FeO to form FeCr2O4.

Investigation of diffusion alloying time on electrochemical behavior and conductivity of Nb-modified AISI 430 SS as PEMFC bipolar plate

2019 ◽  
Vol 66 (4) ◽  
pp. 520-526
Author(s):  
Fupeng Cheng ◽  
Jinglong Cui ◽  
Shuai Xu ◽  
Hongyu Wang ◽  
Pengchao Zhang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Electrochemical Behavior ◽  
Surface Conductivity ◽  
Proton Exchange ◽  
Corrosion Mechanism ◽  
Content Type ◽  
Surface Electrical Conductivity ◽  
Aisi 430

Purpose The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated. Design/methodology/approach In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement. Findings The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests. Originality/value The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.

EIS Study of Bulk Al-SiC Nanocomposite Prepared by Mechanical Alloying and the Hot Press Method

2009 ◽  
Vol 83-86 ◽  
pp. 1297-1305 ◽  
Author(s):  
Taha Rostamzadeh ◽  
H. Shahverdi ◽  
A. Shanaghi ◽  
T. Shahrabi
Keyword(s):  
Corrosion Resistance ◽  
Mechanical Alloying ◽  
Metal Matrix ◽  
Charge Transfer Resistance ◽  
Corrosion Mechanism ◽  
Matrix Composites ◽  
Hot Press ◽  
Ceramic Component ◽  
Transfer Resistance ◽  
Press Method

Metal matrix composites (MMCs) are engineering materials in which a hard ceramic component is dispersed in a ductile metal matrix in order to obtain characteristics such as hardness and corrosion resistance. Corrosion resistance is one of the important properties of nanocomposites; however, the corrosion mechanism of the Al- SiC nanocomposite has not yet been determined. .In this study, bulk Al-5% SiC nanocomposite was prepared using mechanical alloying and the hot press method. Corrosion behavior was then investigated using EIS techniques such as Nyquist and the Bod diagram. A larger charge transfer resistance was found for the Al- SiC nanocomposite by the EIS diagrams, confirming its corrosion resistance in a 3.5wt% NaCl solution.

Correlation of Surface Alloyed Microstructure of Pure Magnesium With its Corrosion Behavior

2012 ◽  
Vol 472-475 ◽  
pp. 161-164
Author(s):  
Yu Gao Liu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Chloride Solution ◽  
Diffusion Time ◽  
Point Of View ◽  
Pure Magnesium ◽  
Corrosion Mechanism ◽  
Cross Sectional ◽  
Microstructure Characteristics ◽  
Solid Diffusion

This paper represents a summary of experimental results dealing with the time dependence of surface diffusion alloyed microstructure and its corrosion behavior at given temperature. The experiments were performed at 485°C for different solid diffusion time (6h, 12h, 18h ) and thus the surface alloyed microstructure of pure magnesium has been obtained. Optical and electrical microscopy and EDS compositions analysis were used to examine the cross sectional microstructure characteristics of alloyed layers of treated samples. It is shown that the new phases formed and its continuity, depending on the diffusion treated time at given temperature, have a noticeable influence on corrosion resistance and corrosion mechanism. The new formed phase Al5Mg11Zn4 was inert to the chloride solution compared with pure magnesium and acted as a corrosion barrier. It was concluded that the continuous Al5Mg11Zn4 phase was beneficial from the point of view of corrosion resistance.

Seawater Corrosion Resistance of Low Heat Portland Cement Concrete

2015 ◽  
Vol 814 ◽  
pp. 207-213
Author(s):  
Ning Wang ◽  
Xiao Wei Cheng ◽  
Yun Xia Yang
Keyword(s):  
Corrosion Resistance ◽  
Portland Cement ◽  
Test Specimen ◽  
Sem Analysis ◽  
Corrosion Mechanism ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Quality Change ◽  
Seawater Corrosion ◽  
Drying Test

With the analysis of the seawater corrosion effect on low-heat Portland cement concrete under wetting-drying test, the compressive strength and quality change of concrete test specimen were investigated for different test periods. According to the evaluation of seawater corrosion resistance, the low-heat Portland cement showed better corrosion resistance than that of ordinary Portland cement and moderate-heat Portland cement. Moreover, the corrosion mechanism was expounded through XRD and SEM analysis. It was found that lots of C2S in the low-heat Portland cement play an important role in corrosion resistance of cement concrete.

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