Effect of Molybdenum on the Microstructures of As-Cast Fe-B Alloys and Their Corrosion Resistance in Molten Zinc

CORROSION ◽  
10.5006/2280 ◽  
2017 ◽  
Vol 73 (8) ◽  
pp. 942-952 ◽  
Author(s):  
Xuemei Ouyang ◽  
Guopeng Chen ◽  
Fucheng Yin ◽  
Ye Liu ◽  
Manxiu Zhao
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Liquid Zinc ◽  
Solid Matrix ◽  
Corrosion Mechanism ◽  
Molten Zinc ◽  
Reticular Structure ◽  
Parabolic Relationship ◽  
Molybdenum Addition

The effect of Mo on the microstructure of as-cast Fe-3.5 B alloys and their corrosion behavior in molten zinc have been investigated. Experimental results show that the as-cast Fe-B alloys with molybdenum addition are mainly composed of α-Fe, Fe2B, FeMo2B2, and metastable Fe3B phases. Corrosion tests show that the Fe-3.5 B alloy with 8.0 wt% added molybdenum has the highest corrosion resistance in molten zinc mainly because the alloy still maintains the reticular structure of boride and improves its thermal stability. When the molybdenum content exceeds 8.0 wt%, the τ-FeMo2B2 + α-Fe eutectic microstructure destroys the reticular structure of the Fe2B phase, leading to reduction in the corrosion resistance of the as-cast Fe-B alloys. Four kinds of corrosion products (δp, δk, ζ, and FeB) were found in the corrosion layers. The corrosion mechanism of Fe-3.5 B alloys with various added molybdenum contents includes the following processes: the preferential corrosion of α-(Fe, Mo), the formation of typical Fe-Zn compounds, the transformation of (Fe, Mo)3B and (Fe, Mo)2B into FeB, and the spalling of borides. The diffusion of molybdenum in the solid matrix cannot occur in the corrosion process. The corrosion depth of the corrosion layer did not follow a parabolic relationship strictly, maybe it caused by the spalling of the corrosion layer under the attack of the liquid zinc. The corrosion process is mainly controlled by the diffusion of liquid zinc atoms.

Research on Corrosion Behavior of Fe-B Eutectic Alloy in Liquid Zinc

2011 ◽  
Vol 311-313 ◽  
pp. 805-810 ◽  
Author(s):  
Rui Na Ma ◽  
Sha Sha Jin ◽  
Hong Yun Li
Keyword(s):  
Corrosion Resistance ◽  
Thermal Stress ◽  
Eutectic Alloy ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Liquid Zinc ◽  
Layer Formation ◽  
Systematic Observation ◽  
Impact Stress ◽  
The Matrix

The static constant corrosion tests on Fe-B eutectic alloy are investigated in liquid zinc at 500°C. The systematic observation and research of the corrosion layer are performed using SEM, TEM, XRD. The results show that corrosion resistance of Fe-B eutectic alloy in liquid zinc is perfect. Corrosion products are Fe3B and FeZn7. The corrosion layer is regular, the structure of which is hollow dendritic skeleton and the thickness of which increases with the corrosion time extending. Corrosion process is that the interdiffusion of ferro and zinc atomic results in corrosion layer formation and the corrosion layer ruptures and dissolves under the action of thermal stress and impact stress of liquid zinc. The process repeating leads to the failure of the matrix eventually.

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

Effect of heat treatment on microstructure and corrosion resistance of extruded ZK80 Mg alloy

2019 ◽  
Vol 9 (9) ◽  
pp. 1092-1099
Author(s):  
Fenghong Cao ◽  
Chang Chen ◽  
Zhenyu Wang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Aging Time ◽  
Room Temperature ◽  
Aging Treatment ◽  
Corrosion Process ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Corrosion Properties

The corrosion characteristics and corrosion mechanism of the extruded ZK80 alloy with different states soaking in 3.5% NaCl solution at room temperature were analyzed via OM, SEM, EDS, XRD and static weightlessness method and other experimental analysis methods. The results show that when the aging temperature is constant, and the corrosion rate decreases with the lengthen of aging time, while when the corrosion time is constant, the corrosion rate increases with the increase in aging time. Appropriate aging treatment not only refines the grain of the alloy, but also precipitates the Mg–Zn phase which can effectively prevent the corrosion process and improve the anti-corrosion properties of the alloy. The main corrosion characteristics of the alloy are filamentary corrosion and pitting corrosion.

Discussion on the Mechanism of Corrosion Resistance of High Temperature QPQ Treated Specimens in H2S Environment

2011 ◽  
Vol 66-68 ◽  
pp. 665-668
Author(s):  
Yuan Hui Li ◽  
Shi Ping Zhang ◽  
Yi Chao Ding ◽  
Zi Lian Jiang
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Hydrogen Atom ◽  
Volume Expansion ◽  
Steel Specimen ◽  
Compound Layer ◽  
Corrosion Layer ◽  
Corrosion Mechanism ◽  
Diffusion Of Hydrogen ◽  
Coefficient Of Diffusion

By constant stress tensile test, the corrosion mechanism of high temperature QPQ treated 25CrMnMo steel specimen in H2S environment was analyzed and discussed. The γ′-Fe4N in the ε compound layer turns into corrosion substance in the test and expands. At the surface of the ε compound layer, the corrosion layer is visible. The compound layer breaks off in little blocks for volume expansion of the corrosion substance and the exterior tensile stress. The coefficient of diffusion of hydrogen atom in the ε compound layer is very low, that decrease the probability of the hydrogen-induced corrosion of high temperature QPQ treated specimens in H2S environment.

Corrosion Resistance of Fe-B Alloys Immersed in Molten Zinc Bath

2011 ◽  
Vol 383-390 ◽  
pp. 3051-3055
Author(s):  
Xiao Ming Cao ◽  
Peng Fei Yin ◽  
Rui Na Ma
Keyword(s):  
Corrosion Resistance ◽  
Energy Dispersive Spectrum ◽  
Eutectic Structure ◽  
Corrosion Property ◽  
Corrosion Mechanism ◽  
Zinc Bath ◽  
Molten Zinc ◽  
The Matrix ◽  
Fe2b Phase ◽  
Resistance Performance

Fe-B alloys with different boron contents were dipped into a pure molten zinc bath to investigate their anti-corrosion property. Scanning electron microscope (SEM) and energy dispersive spectrum(EDS) were used to detect the corrosion products. It is found that the corrosion mechanism of α phase is corrosion and dissolution ,while the Fe2B phase is crack mechanism because of its brittleness and excellent corrosion resistance.The Fe2B phase in eutectic structure can protect the matrix from molten zinc and restrict the reaction of Fe-Zn. With the increase of boron content, the corrosion resistance performance of the alloys improves gradually.

Investigation on the corrosion resistance of laser cladding Fe-based alloy coating against molten zinc

CORROSION ◽  
10.5006/3877 ◽  
2022 ◽  
Author(s):  
Qian Wang ◽  
Liang Zhang ◽  
Junwei Zhang
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Transition Layer ◽  
Steel Substrate ◽  
Alloy Coating ◽  
Corrosion Layer ◽  
Skeletal Structure ◽  
H13 Steel ◽  
Molten Zinc ◽  
Α Phase

In this paper, laser cladding technology was used to prepare a Fe-based coating on H13 steel substrate and its corrosion behavior in molten zinc was studied. The results show that laser-cladding Fe-based coating can effectively protect the substrate from the corrosion of molten zinc, which is mainly related to its microstructure. The typical microstructure of the coating is composed of α-(Fe, Cr) solid solution matrix and CrFeB eutectic phases continuously distribute around the matrix. When molten zinc contacts with the surface of the coating, it corrodes the α phase matrix preferentially and CrFeB eutectic phases with better corrosion resistance interweave with each other to form a three-dimensional skeletal structure, which can play the role of diffusion barrier and slow down the diffusion rate of liquid zinc. The corrosion by molten zinc leads to the formation of a transition layer and an outer corrosion layer above the coatings. With the prolongation of the corrosion time, a large number of micro cracks are generated inside the transition layer and fracture gradually occurs under the action of thermal stress. The partial spalling of the transition layer and the corrosion of α phase matrix occur at the same time, making the corrosion depth of the coating increase continuously. However, the dense corrosion layer above the coating and the dispersed boride fragments can still function as a barrier to the inward diffusion of molten zinc.

PYRODUR 4923

Alloy Digest ◽  
2018 ◽  
Vol 67 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
Scaling Up ◽  
Maximum Hardness ◽  
Temperature Performance ◽  
Molybdenum Addition

Abstract Pyrodur 4923 is a high-temperature resistant stainless steel with molybdenum addition. Special properties include resistant to scaling up to around 600 C (1110 F), and maximum hardness approximately 590 Hv. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1277. Producer or source: Deutsche Edelstahlwerke.

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.

Evaluation of the corrosion behavior of AZ31 magnesium alloy with different protein concentrations

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yucong Ma ◽  
Mohd Talha ◽  
Qi Wang ◽  
Zhonghui Li ◽  
Yuanhua Lin
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Surface Film ◽  
Energy Dispersive Spectrometer ◽  
Inhibitory Effect ◽  
Corrosion Process ◽  
High Concentration ◽  
Content Type ◽  
Atomic Force

Purpose The purpose of this paper is to study systematically the corrosion behavior of AZ31 magnesium (Mg) alloy with different concentrations of bovine serum albumin (BSA) (0, 0.5, 1.0, 1.5, 2.0 and 5.0 g/L). Design/methodology/approach Electrochemical impedance spectroscopy and potential dynamic polarization tests were performed to obtain corrosion parameters. Scanning electrochemical microscopy (SECM) was used to analyze the local electrochemical activity of the surface film. Atomic force microscope (AFM), Scanning electron microscope-Energy dispersive spectrometer and Fourier transform infrared spectroscopy were used to determine the surface morphology and chemical composition of the surface film. Findings Experimental results showed the presence of BSA in a certain concentration range (0 to 2.0 g/L) has a greater inhibitory effect on the corrosion of AZ31, however, the presence of high-concentration BSA (5.0 g/L) would sharply reduce the corrosion resistance. Originality/value When the concentration of BSA is less than 2.0 g/L, the corrosion resistance of AZ31 enhances with the concentration. The adsorption BSA layer will come into being a physical barrier to inhibit the corrosion process. However, high-concentration BSA (5.0 g/L) will chelate with dissolved metal ions (such as Mg and Ni) to form soluble complexes, which increases the roughness of the surface and accelerates the corrosion process.

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