scholarly journals Effect of Ca Element on Microstructure and Corrosion Behavior of Single-Phase Mg–Sc Alloy

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Cheng Zhang ◽  
Cheng Peng ◽  
Jin Huang ◽  
Yanchun Zhao ◽  
Tingzhuang Han ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Single Phase ◽  
Phase Particle ◽  
Test Results ◽  
Corrosion Product Film ◽  
Product Film ◽  
Protective Performance ◽  
Scanning Electron

The effect of Ca on the microstructure and corrosion behavior of a single-phase Mg–Sc alloy was investigated. The microstructure was characterized by optical microscopy and scanning electron microscopy. Corrosion behavior was measured by hydrogen evolution tests and electrochemical measurements. With the addition of microalloyed Ca, the grain size of Mg-0.3Sc alloy is refined and the Mg2Ca phase particle is precipitated. The corrosion test results reveal that the addition of microalloyed Ca is beneficial to the corrosion resistance of Mg-0.3Sc single-phase alloy, which is related to the grain refinement and the protective performance of the corrosion product film. As the content of Ca increases, the corrosion resistance of the alloy first increases and then decreases, which is mainly related to the microstructure of the alloy.

An Improvement in Tarnish and Corrosion Resistance of 94Ag-4Zn-Cu Alloys with Sn Addition

2014 ◽  
Vol 894 ◽  
pp. 138-142 ◽  
Author(s):  
Jirutthitikalpongsri Hirunyagird ◽  
Gobboon Lothongkum ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Single Phase ◽  
Corrosion Current ◽  
Eutectic Structure ◽  
Test Results ◽  
High Solubility ◽  
Cu Alloys ◽  
The Matrix ◽  
Tin Content

The tarnish and corrosion resistance of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy compared with Ag-5.95Cu alloy were investigated. The tarnish results show that the DE* value of Ag-5.95Cu alloy is higher than those of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy due to the sulfide formations such as Ag2S, Cu2S and CuS. The DE* value significantly decreases with increasing tin content. This is attributed to the matrix enrichment of tin which protects the sulfur reaction on surface. From corrosion test results, 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy provide the noble shift in the corrosion potentials and pitting potentials but the negative shift in the corrosion current density compared with Ag-5.95Cu alloy. Corrosion rate of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy decrease markedly compared with Ag-5.95Cu alloy because it depends on the alloying elements and the microstructural changes. Due to high solubility of zinc and tin, the microstructures of tin-rich alloys consist of the higher portion of single phase and less eutectic structure than that of Ag-5.95Cu alloy.

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 Effect of Weld and Surface Defects on the Corrosion Behavior of Nickel Aluminum Bronze in 3.5% NaCl Solution

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1227
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Jintao Wang ◽  
Tianxiang Peng ◽  
Zhanping Zhang ◽  
...  
Keyword(s):  
Corrosion Product ◽  
Corrosion Behavior ◽  
Early Stage ◽  
Optical Microscope ◽  
Aluminum Bronze ◽  
Nickel Aluminum ◽  
Nacl Solution ◽  
Corrosion Product Film ◽  
Product Film ◽  
Nickel Aluminum Bronze

To study the effect of weld and defects on the corrosion behavior of nickel aluminum bronze (UNS C95810) in 3.5% NaCl solution, the weight loss, X-ray diffraction, optical microscope, scanning electron microscope and electrochemical test of the specimen with weld and defects were investigated. The results show that the presence of weld and defects increases the corrosion rate of bronze. Weld does not change the structure of the corrosion product film, but defects induce a lack of the protective outermost corrosion product in bronze. Weld makes the corrosion product film in the early stage more porous. Defects always produce an increase in the dissolution rate of the bronze.

Fast Electroless Ni-P Coating on AM60 Magnesium Alloy at Low Bath Temperature

2011 ◽  
Vol 418-420 ◽  
pp. 756-759 ◽  
Author(s):  
Guo Bing Mao
Keyword(s):  
Growth Rate ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Electroless Plating ◽  
Corrosion Test ◽  
Bath Temperature ◽  
Test Results ◽  
Electroless Ni

The Ni-P coatings were deposited on AM60 magnesium alloy by electroless plating process without or with accelerators. Without accelerators, the deposition rate is slow and required high bath temperature to obtain compact coating. There have many defects on the surface of the Ni-P coatings which deposited at high bath temperature. The composite accelerators were introduced into the bath for improving the growth rate and the quality of the Ni-P coating. Uniform, with no pores or cracks, “cauliflower-like” structure and complete Ni-P coatings were deposited only taken 20 min with additives at low bath temperature. The XRD result indicates that the structure of the Ni-P coating is amorphous nickel. The corrosion test results indicated that the corrosion resistance of this coated AM60 magnesium alloys increases distinctly as compared to bare alloys.

Characterization and hot corrosion behavior of D-gun sprayed Cr2O3-75% Al2O3 coated ASTM-SA210-A1 boiler steel in molten salt environment

2017 ◽  
Vol 64 (5) ◽  
pp. 515-528 ◽  
Author(s):  
Amita Rani ◽  
Niraj Bala ◽  
C.M. Gupta
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Molten Salt ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Degradation Mechanism ◽  
Effective Diffusion ◽  
Boiler Steel ◽  
Content Type ◽  
Scanning Electron

Purpose Hot corrosion is the major degradation mechanism of failure of boiler and gas turbine components. The present work aims to investigate the hot corrosion resistance of detonation gun sprayed (D-gun) Cr2O3-75 per cent Al2O3 ceramic coating on ASTM-SA210-A1 boiler steel. Design/methodology/approach The coating exhibits nearly uniform, adherent and dense microstructure with porosity less than 0.8 per cent. Thermogravimetry technique is used to study the high temperature hot corrosion behavior of bare and coated boiler steel in molten salt environment (Na2SO4-60 per cent V2O5) at high temperature 900°C for 50 cycles. The corrosion products are analyzed by using X-ray diffraction, scanning electron microscopy (SEM) and field emission scanning electron microscope/energy-dispersive analysis (EDAX) to reveal their microstructural and compositional features for elucidating the corrosion mechanisms. Findings During investigations, it was found that the Cr2O3-75 per cent Al2O3 coating on Grade A-1 boiler steel is found to be very effective in decreasing the corrosion rate in the molten salt environment at 900°C. The coating has shown lesser weight gains along with better adhesiveness of the oxide scales with the substrate till the end of the experiment. Thus, coatings serve as an effective diffusion barrier to preclude the diffusion of oxygen from the environment into the substrate boiler steel. Research limitations/implications Therefore, it is concluded that the better hot corrosion resistance of the coating is due to the formation of desirable microstructural features such as very low porosity, uniform fine grains and the flat splat structures in the coating; as compared to the bare substrate under cyclic conditions. Practical implications This research is useful for coal-fired boilers and other power plant boilers. Social implications This research is useful for power generation plants. Originality/value There is no reported literature on hot corrosion behavior of Cr2O3-75 per cent Al2O3 coating deposited on the selected substrates by D-gun spray technique. The present work has been focused to study the influence of the Cr2O3-75 per cent Al2O3 coating developed with D-gun spraying technique on high temperature corrosion behavior of ASTM-SA210-A-1 boiler steel in an aggressive environment of Na2SO4-60 per cent V2O5 molten salt at 900°C under cyclic conditions.

Corrosion Product Films Formed on Aluminum In High Temperature Wester

CORROSION ◽  
1961 ◽  
Vol 17 (4) ◽  
pp. 181t-184t ◽  
Author(s):  
D. F. MacLENNAN
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Aluminum Alloys ◽  
Corrosion Product ◽  
High Purity ◽  
Second Phase ◽  
Corrosion Product Film ◽  
Second Phase Particles ◽  
Product Film

Abstract A study was made of the behavior of aluminum alloys exposed to 300 G high purity water for short periods of time. The corrosion products formed were examined by means of optical and electron microscopy. Results show that corrosion resistance is associated with the distribution of second phase particles in the alloys. The alloy, which had the best corrosion resistance, contained the most uniform distribution of cathodic second phase particles; the corrosion product film of this alloy contained a corresponding distribution of irregularities. It is suggested that the second phase particles modify the film in such a way as to increase its protective qualities. 6.4.2, 4.6.5, 3.2.3

Effect of iron on the composition and structure of corrosion product film formed in 70/30 copper-nickel alloy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanbo Zhu ◽  
Xiaohong Chen ◽  
Ping Liu ◽  
Shaoli Fu ◽  
Honglei Zhou ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Nickel Alloy ◽  
Corrosion Product ◽  
Content Type ◽  
X Ray ◽  
Corrosion Product Film ◽  
Copper Nickel ◽  
Composition And Structure ◽  
Product Film ◽  
Copper Nickel Alloy

Purpose This study aims to investigate the effect of changes in iron content in 70/30 copper–nickel alloy on the corrosion process. Design/methodology/approach 70Copper–30Nickel-xFe-1Mn (x = 0.4,0.6,0.8,1.0 Wt.%) alloy were prepared by the high frequency induction melting furnace. The scanning electron microscope, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to analyze the morphology and component of the corrosion product film. Findings The results show that the corrosion resistance of 70/30 copper–nickel alloy added with 1.0%Fe is the best, and the film is divided into inner dense Cu2O composite film and outer hydration loose layer; XRD showed that after adding 1.0% Fe, the content of Cu2(OH)3Cl in the corrosion product film was significantly reduced, while the content of Cu2O remained unchanged; XPS showed that nickel accumulates in the inner layer of corrosion product film; the stage growth mode of the film, the role of nickel in it and the enrichment mechanism of iron in the inner film were summarized and discussed. Originality/value The changes in the composition and structure of the corrosion product film caused by the iron content are revealed, and the mechanism of the difference in corrosion resistance is discussed.

Corrosion behavior of X80 pipeline steel in oilfield injection water in Eastern China

2021 ◽  
Vol 68 (5) ◽  
pp. 438-448
Author(s):  
Haoping Peng ◽  
Zhaolin Luan ◽  
Jun Liu ◽  
Yun Lei ◽  
Junxiu Chen ◽  
...  
Keyword(s):  
Corrosion Product ◽  
Corrosion Behavior ◽  
Pipeline Steel ◽  
Eastern China ◽  
Immersion Test ◽  
X80 Pipeline Steel ◽  
Content Type ◽  
Corrosion Product Film ◽  
Product Film ◽  
Injection Water

Purpose This paper aims to under the laboratory environment, the corrosion behavior of X80 pipeline steel in oilfield injection water in eastern China was studied by immersion test. Design/methodology/approach First, the corrosion product film was immersed in oilfield injection water and the effect on the corrosion behavior and the corrosion reaction mechanism were constantly observed during this period. The effect was displayed by potentiodynamic polarization curve and electrochemical impedance spectrums (EIS) measurements. Second, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to observe and test the corrosion product film immersed in the oilfield water for 30 days. Findings The results indicate that the tendency of metal corrosion becomes weaker at an early stage, but strengthened later, which means the corrosion rate is accelerating. Besides, it is indicated by impedance spectroscopy that with the decreasing of the capacitance arc radius, the reaction resistance is reducing in this progress. Meanwhile, the character of Warburg impedance could be found in EIS, which means that the erosional components are more likely to penetrate the product film to reach the matrix. The corrosion product is mainly composed of the inner Fe3O4 layer and outer shell layer, which contains a large number of calcium carbonate granular deposits. It is this corrosion under fouling that produces severe localized corrosion, forming many etch pits on the metal substrate. Originality/value The experiment chose the X80 steel, the highest-grade pipeline steel used in China, to conduct the static immersion test in the injection water coming from an oilfield in eastern China. Accordingly, the corrosion mechanism and the effect of corrosion product film on the corrosion of pipeline steel were analyzed and discussed.

Preparation and Salt Spray Corrosion Resistance of Ni/BN and NiCrAl/BN Coatings

2013 ◽  
Vol 537 ◽  
pp. 67-70
Author(s):  
Feng Zhang ◽  
Chuan Bing Huang ◽  
Wei Liu ◽  
Kui Zhou ◽  
Wen Ting Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Open Circuit Potential ◽  
Salt Spray ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
Salt Spray Corrosion ◽  
X Ray ◽  
Corrosion Behaviors ◽  
Scanning Electron

Ni/BN and NiCrAl/BN abradable sealing coatings used in turbo engines were prepared by plasma spray technology. The phases and the microstructures of the coatings were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Corrosion behaviors of these coatings were investigated with open-circuit potential (OCP) and salt spray corrosion test. The results showed that the NiCrAl/BN possess better corrosion resistance as compared with Ni/BN.

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