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 ◽  
...  

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.

2014 ◽  
Vol 548-549 ◽  
pp. 177-181
Author(s):  
Ping Wang ◽  
Zhao Hui Yin ◽  
Han Tao Ren ◽  
Song Xu ◽  
Dong Wei Ma

The losses due to copper corrosion in H2S atmospheric corrosion have attracted much focus. It’s important to improve copper corrosion resistance that the corrosion law, corrosion mechanism and characteristics were studied in H2S environment. This paper reviewed the corrosion behavior of copper, analyzed the impact of environment factors and corrosion analysis tools. Through evaluating and improving corrosion by external factors, including improving corrosive environment, using coating protection and adding corrosion inhibitors, appropriate corrosion measures were taken to extend the life of the equipment.


2009 ◽  
Vol 79-82 ◽  
pp. 957-960 ◽  
Author(s):  
Li Jie Yue ◽  
Wei Gong Chen

The weather resistance of 10CuPRE、10CuP and Q235 steels were studied by dry-wet cyclic immersion test. The corrosion resistance mechanism of rare earth Cu-containing weathering steel was studied through electrochemical polarization test, scanning electron microscope(SEM) and X ray diffraction(XRD). The results show the small and spherical rare earth oxysulfides replace the elongated MnS inclusions in the rare earth weathering steel. Less and fewer rare earth oxysulfides heavily decrease pitting susceptibility and rate of pit propagation. So the electrochemical corrosion of microarea in the steel matrix is weakened after rare earth was added in the Cu-containing weathering steel. The inner rust layer of rare earth weathering steel is more compact and uniform than that of weathering steel without rare earth. The main corrosion product on the rare earth weathering steel is α-FeOOH. The formation of the steady corrosion product is promoted by rare earth, which result in that the protective property of the inner rust layer on weathering steels is enhanced. As a result, the corrosion resistance of Cu-containing weathering steel is improved by rare earth elements.


2014 ◽  
Vol 789 ◽  
pp. 622-626
Author(s):  
Peng Chao Zhang ◽  
Jian Zhang ◽  
Jin Chuan Jie ◽  
Yuan Gao ◽  
Yong Dong ◽  
...  

The effect of different alloying elements on corrosion behavior of copper alloys was investigated using electrochemical corrosion and salt spray corrosion test in NaCl solution. Cu-Ag has the most stable corrosion current in the potentiostatic scanning test, exhibiting a better corrosion resistant performance. It can be analyzed from corrosion surface morphologies that Cu-Ag presents exfoliation corrosion mechanism while Cu-Sn shows crevice corrosion mechanism. Cu-Mg has a complex corrosion process caused by multiple corrosion mechanism. In the salt spray corrosion test, the corrosion degree of Cu-Ag is lighter than those of Cu-Sn and Cu-Mg after 24h test. Therefore, the Cu-Ag alloy exhibits the best corrosion resistance in chloride solution.


2012 ◽  
Vol 472-475 ◽  
pp. 161-164
Author(s):  
Yu Gao Liu

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.


2016 ◽  
Vol 23 (3) ◽  
pp. 309-314
Author(s):  
M. Edwin Sahayaraj ◽  
J.T. Winowlin Jappes ◽  
I. Siva ◽  
N. Rajini

AbstractElectroless nickel coating treatment improves the corrosion resistance of mild steel. This work aims at studying the corrosion behavior of electroless Ni-P/TiO2 composite and multilayer coatings applied to the mild steel substrate as their as-plated state and furnace annealed at various temperatures and compared both the coatings’ corrosion performance. The corrosion behavior of the deposits was evaluated by potentiodynamic polarization studies in 3.5 wt% sodium chloride solution. The results showed that the corrosion resistance of the multilayer coating was two times higher compared to the composite coatings. Further, the corrosion mechanism was discussed in terms of microstructure, phase transformation, grain size, and microstrain.


2013 ◽  
Vol 740 ◽  
pp. 608-611 ◽  
Author(s):  
Ming Hua Liang ◽  
Zhi Yong Pan ◽  
Xiang Zhang

The influence of Cr on corrosion behavior of P110 steel was studied in the simulated CO2 environment. The result demonstrated that the Cr cant change the effect of temperature on P110 steel. The corrosion rates of the two kinds of materials reached the peak at 90°C. The temperature has dual effects on corrosion, which caused the adhesive and productivity of corrosion product formed up 90°C are better than that formed below 90°C; The adding of Cr in the P110 steel can prohibit the local corrosion to occur.


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