Corrosion Behavior of Enamel Coated Steel Rebar by EIS

2012 ◽  
Vol 450-451 ◽  
pp. 445-453 ◽  
Author(s):  
Fu Jian Tang ◽  
Gen Da Chen ◽  
Jeffery S. Volz ◽  
Richard K. Brow ◽  
Michael Koenigstein
Keyword(s):  
Corrosion Resistance ◽  
Pore Structure ◽  
Enamel Coating ◽  
Surface Condition ◽  
Corrosion Process ◽  
Coated Steel ◽  
Nacl Solution ◽  
Steel Rebar ◽  
Interconnected Pore ◽  
Interconnected Pore Structure

In this study, the corrosion process of enamel-coated deformed rebar completely immersed in 3.5 wt.% NaCl solution was evaluated over a period of 84 days by EIS testing. Three types of enamel coating were investigated: pure enamel, 50/50 enamel coating, and double enamel. Surface condition of the enamel coatings that were intentionally damaged prior to corrosion tests was visually examined at different immersion times. After 84 days of testing, the damaged coating areas were characterized by SEM, and the corrosion products on and adjacent to the damaged areas were collected and analyzed by XRD. Corrosion initiated at the damaged locations with no undercutting of the coating observed. The 50/50 enamel coating had the least corrosion resistance, due to its interconnected pore structure, and prior damage drastically reduced the corrosion resistance of pure and double enamel coated rebar.

Effect of Osmotic Pressure by Salt Concentration on Corrosion Resistance of Anti-Corrosive Paint

2018 ◽  
Vol 926 ◽  
pp. 31-36
Author(s):  
Kyung Man Moon ◽  
Myeong Hoon Lee ◽  
Tae Sil Baek
Keyword(s):  
Corrosion Resistance ◽  
Osmotic Pressure ◽  
Salt Concentration ◽  
Corrosion Current Density ◽  
Steel Plate ◽  
Chloride Ion ◽  
Corrosion Current ◽  
Coating Film ◽  
Coated Steel ◽  
Nacl Solution

Recently, many types of constructional steels have been often exposed to severely corrosive environments due to acid rain with increasing environmental contamination. To control corrosion problems, a painting protection method has been widely applied to numerous constructional steels on land as well as offshore. Therefore, development of anti-corrosive paint with good quality of corrosion resistance is very important from an economical perspective. In this study, four types of anti-corrosive paint were coated to test specimens, and then, were immersed in various salt solutions (0.1, 3 and 9% NaCl solution) for 11 days. Corrosion resistance of these samples by effect of osmotic pressure with various salt concentration was investigated with electrochemical methods such as measurement of corrosion potential, impedance and corrosion current density. Corrosion current density of these samples submerged in 0.1% NaCl solution exhibited highest value than those immersed in 3% and 9% NaCl solutions because water, dissolved oxygen and chloride ion etc. is easily to invade towards inner side of coating film due to increasing osmotic pressure compared to 3% and 9% NaCl solutions. However, corrosion current densities of all samples in the case of submerged in 9% NaCl solution exhibited higher values compared to 3% NaCl solution.Thus, a large amount of chloride ion dissolved in 9% NaCl solution plays a more critical role in corrosion behavior of coated steel rather than osmotic pressure. Consequently, the corrosion mechanism between coated steel and bare steel plates is different from each other because of presence of osmotic pressure between salt solution and coating film of coated steel plate. As a result, corrosion resistance of tcoated steel plate may be depend on the osmotic pressure as well as salt concentration

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.

scholarly journals Interconnected PVDF-CTFE hydrophobic membranes for MD desalination: effect of PEGs on phase inversion process

RSC Advances ◽  
2016 ◽  
Vol 6 (25) ◽  
pp. 20926-20937 ◽  
Author(s):  
Libing Zheng ◽  
Jun Wang ◽  
Yuansong Wei ◽  
Yong Zhang ◽  
Kun Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pore Structure ◽  
Phase Inversion ◽  
Pore Distribution ◽  
Inversion Process ◽  
Hydrophobic Membranes ◽  
Interconnected Pore ◽  
Interconnected Pore Structure ◽  
Phase Inversion Process

PVDF-CTFE membrane with interconnected pore structure, narrow pore distribution, and high DCMD performance was prepared by study the effect of molecular weight and dosage of PEG.

Influence of Various Heat Treatment on Corrosion Resistance of As-Extruded Mg-9Li-3Al-2.5Sr Alloys

2014 ◽  
Vol 788 ◽  
pp. 41-44 ◽  
Author(s):  
Yuan Qing Yu ◽  
Xiao Dong Peng ◽  
Hong Yu Yi ◽  
Jun Wei Liu
Keyword(s):  
Corrosion Resistance ◽  
Intermetallic Compounds ◽  
Unit Volume ◽  
Aging Treatment ◽  
Corrosion Current ◽  
Immersion Test ◽  
Corrosion Process ◽  
Nacl Solution ◽  
Boundary Area ◽  
Solution Treated

The corrosion behavior of Mg-9Li-3Al-2.5Sr alloy, solution treated at 400°C for 3h with various aging temperature (Ta; Ta=75,100,125,150,175°C), was investigated in 3.5% NaCl solution by immersion test and polarization curve measurement. Experimental results suggest that the alloy aged at150°Cfor 6h exhibits the highest corrosion resistance while the alloy treated at 75°C for 6h presents lowermost corrosion resistance. The corrosion resistance of the alloy is related to the grain size and the distribution of Al4Sr compound. The segregation of intermetallic compounds can accelerate the corrosion process. It was found that duo to the proper solid-solution and aging treatment, intermetallic compounds were distributed evenly along the grain boundaries, which can reduce the corrosion rate and corrosion current. In addition,with the growth of grain, the decrease of the grain boundary area per unit volume lead to improvement of corrosion resistance of the alloys.

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