scholarly journals Preparation of Coating on the Titanium Surface by Micro-Arc Oxidation to Improve Corrosion Resistance

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 230 ◽  
Author(s):  
Yulong Hu ◽  
Zhiqiao Wang ◽  
Jianyang Ai ◽  
Shichao Bu ◽  
Hongwei Liu
Keyword(s):  
Corrosion Resistance ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Coating Structure ◽  
Lower Porosity ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Different Thickness

In this paper, two kinds of micro-arc oxidation (MAO) coatings on TA2 with different thickness were prepared by controlled oxidation time and then were characterized for their composition, crystalline structure, and surface morphology. The effect of MAO treatment on electrochemical corrosion behaviors of TA2 in 3.5% NaCl solution were studied by the electrochemical measurements including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves. The results indicate that the electrochemical behavior of MAO coating is related to the coating structure. OCP can be used to evaluate the porosity of MAO coating. More positive OCP indicates coating with lower porosity and larger resistance obtained from EIS. The MAO treatment can significantly enhance the corrosion resistance of TA2, but the thickness increase of MAO coating could not further improve the corrosion resistance. In addition, because of the increase in effective surface area, the MAO treatment may enhance the cathode action of TA2 when the galvanic cell is composed of TA2 and other more negative metal, which in turn promotes the corrosion of negative metal.

Electrochemical corrosion behavior of HVOF sprayed WC–12Co coating on H13 hot work mould steel

2019 ◽  
Vol 66 (6) ◽  
pp. 827-834
Author(s):  
Kong Weicheng ◽  
Shen Hui ◽  
Gao Jiaxu ◽  
Wu Jie ◽  
Lu Yuling
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Curvature Radius ◽  
Nacl Solution ◽  
Content Type ◽  
Capacitance Curve ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors

Purpose This study aims to investigate the electrochemical corrosion performance of high velocity oxygen fuel (HVOF) sprayed WC–12Co coating in 3.5 Wt.% NaCl solution, which provided a guiding significance on the corrosion resistance of H13 hot work mould steel. Design/methodology/approach A WC–12Co coating was fabricated on H13 hot work mould steel using a HVOF, and the electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution was measured using open circuit potential (OCP), potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) tests. Findings The OCP and PPC of WC–12Co coating positively shift than those of substrate, its corrosion tendency and corrosion rate decrease to enhance its corrosion resistance. The curvature radius of capacitance curve on the WC–12Co coating is larger than that on the substrate, and the impedance and polarization resistance of WC–12Co coating increase faster than those of substrate, which reduces the corrosion process. Originality/value The electrochemical corrosion behaviors of WC–12Co coating and substrate in 3.5 Wt.% NaCl solution is first measured using OCP, PPC and EIS tests, which improve the electrochemical corrosion resistance of H13 hot work mould steel.

scholarly journals Microstructure and Corrosion Resistance to H2S in the Welded Joints of X80 Pipeline Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1325 ◽  
Author(s):  
Jian-Bao Wang ◽  
Guang-Chun Xiao ◽  
Wei Zhao ◽  
Bing-Rong Zhang ◽  
Wei-Feng Rao
Keyword(s):  
Corrosion Resistance ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Coarse Grained ◽  
Granular Bainite ◽  
X80 Pipeline Steel

The microstructure and corrosion resistance in H2S environments for various zones of X80 pipeline steel submerged arc welded joints were studied. The main microstructures in the base metal (BM), welded metal (WM), coarse-grained heat-affected zone (CGHAZ), and fine-grained heat-affected zone (FGHAZ) were mainly polygonal ferrite and granular bainite; acicular ferrite with fine grains; granular bainite, ferrite, and martensite/austenite constituents, respectively. The corrosion behavior differences resulted from the microstructure gradients. The results of the micro-morphologies of the corrosion product films and the electrochemical corrosion characteristics in H2S environments, including open circuit potential and electrochemical impedance spectroscopy, showed that the order of corrosion resistance was FGHAZ > BM > WM > CGHAZ.

Influences of Grain Size on Electrochemical Corrosion Behaviors of Nickel-Based Alloy 718

2016 ◽  
Vol 852 ◽  
pp. 105-112 ◽  
Author(s):  
Yan Mo ◽  
Dong Zhe Wang ◽  
Bin Jiang ◽  
Yong You Li ◽  
Hai Ding Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Sea Water ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Structure Design ◽  
Coarse Grained ◽  
Alloy 718 ◽  
Corrosion Behaviors ◽  
Nickel Based Alloy

With the application upgrade of alloy 718 in the marine oil exploitation, higher corrosion resistance demands has been presented for structure design and reasonable material application of drilling and production equipments; thus there is an urgent need to understand influences of grain size on corrosion behavior of such alloy in sea water environment. In this experiment, different solution treatments are applied to nickel-based alloy 718. As a result, specimens with grain size varied from ASTM No. 9 to No. 3.5 grades. The influences of grain size on the electrochemical behaviors in simulated sea water (3.5% sodium chloride solution) are investigated using electrochemical impedance spectroscopy and polarization curves. Alloy 718 shows good corrosion resistance in this electrolyte solution, however, grain size still has an effect on its electrochemical corrosion behaviors to a certain extent. With the time going, testing results show that coarse-grained alloys with larger grain size have higher impedance values and smaller corrosion current densities, indicating a better corrosion resistance than fine-grained specimens. However, when the grain size increases further, the corrosivity resistant nature of alloy 718 would decline. Testing results show that specimen with size of ASTM No. 5 has the best corrosion resistance.

Electrochemical Behaviors of Die-Cast Mg-4Al-0.4Mn-Xpr (x=0, 1, 4) Alloys in NaCl Solution

2013 ◽  
Vol 690-693 ◽  
pp. 82-88
Author(s):  
Xiao Dong Niu ◽  
Wei Sun ◽  
Xin Qiu ◽  
Jian Meng ◽  
Jian An
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Nacl Solution ◽  
Electrochemical Behaviors ◽  
Β Phase ◽  
Die Cast ◽  
Corrosion Behaviors ◽  
Potential Test

The microstructures and electrochemical corrosion behaviors of die-cast Mg-4Al-0.4Mn-xPr (x=0, 1, 4 wt.%) alloys have been investigated. Electrochemical behaviors of all alloys are described by open circuit potential test, potentiodynamic polarization test and electrochemical impedance spectroscope in 3.5 wt.% NaCl solution. The results show that the α-Mg grain is refined and the continuous net β phase appears gradually with increasing the content of Pr in the Mg-4Al-0.4Mn alloys. Moreover, the β phase plays a role of galvanic cathode in AM40 alloy and corrosion barrier in Pr-containing alloys, respectively. Electrochemical measurements show that Pr can improve corrosion resistance of Mg-4Al-0.4Mn alloy in the 3.5 wt.% NaCl solution, and corrosion rate decreases with increasing Pr content.

scholarly journals Effect of Cu Addition on the Electrochemical Corrosion Performance of Ni3Al in 1.0 M H2SO4

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodriguez-Diaz ◽  
E. Porcayo-Palafox ◽  
J. Colin ◽  
A. Molina-Ocampo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Intermetallic Alloy ◽  
Intermetallic Alloys ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Electrochemical Corrosion Behavior

The effect of Cu addition on the electrochemical corrosion behavior of Ni3Al intermetallic alloy was investigated by potentiodynamic polarization, open-circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy in 1.0 M H2SO4solution. Performance of the pure elements (Cu, Ni, and Al) was also evaluated. In general, Cu addition improved the corrosion resistance of Ni3Al. Electrochemical measurements show that corrosion resistance of Ni3Al-1Cu alloy is lower than that of other intermetallic alloys and pure elements (Ni, Cu, and Al) in 1.0 M H2SO4solution at 25°C. Surface analysis showed that the Ni3Al alloys are attacked mainly through the dendritic phases, and Cu addition suppresses the density of dendritic phases.

Electrochemical Corrosion Behaviors of CuZrHfTi Bulk Metallic Glasses in NaOH Solution

2012 ◽  
Vol 178-181 ◽  
pp. 1075-1078
Author(s):  
Bin Sun ◽  
Wen Yong Zhang ◽  
Jin Bin Lu
Keyword(s):  
Corrosion Resistance ◽  
Current Density ◽  
Metallic Glasses ◽  
Electrochemical Impedance ◽  
Bulk Metallic Glasses ◽  
Electrochemical Corrosion ◽  
Transfer Resistance ◽  
Naoh Solution ◽  
Corrosion Behaviors ◽  
Passivation Current Density

The electrochemical corrosion behaviors of Cu60Zr30-xHfxTi10(x=10,15,20) bulk metallic glasses (BMGs) were investigated in 3 mol/L NaOH solution by potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results showed that the BMGs had sufficient corrosion resistance in NaOH solution. The anodic showed grading passivation character, and the passivation current density were very low. The corrosion resistance changed with Hf content changing. The passivation current density of Cu60Zr15Hf15Ti10 alloy was lowest and the charge transfer resistance was largest, which means the best corrosion resistance for CuZrHfTi BMGs. Corrosion mechanisms were not changed, while the corrosion resistance decrease after crystallized for the BMGs.

Electrochemical Corrosion of As-Cast and Annealed Zr48Cu36Al8Ag8 BMG in 0.1 M NaCl Solution

2016 ◽  
Vol 863 ◽  
pp. 65-69
Author(s):  
Jing Chie Lin ◽  
Mao Chia Huang ◽  
Ongki B. Anggriawan ◽  
Jason Shian Ching Jang ◽  
M. Agus Choiron
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Crystal Defects ◽  
Crystal Phase ◽  
Annealing Duration ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Cast Specimen

Electrochemical corrosion of as-cast and annealed zirconium-based bulk metallic glass (BMG) Zr48Cu36Al8Ag8 in 0.1 M NaCl solution was investigated in this work. The as-cast specimen, in complete amorphous form, contained null percent of crystal phase (denoted as 0C); however, the annealed ones contained 11, 25, 50, 75 and 100 % crystal phase (denoted as 11C, 25C, 50C, 75C and 100C, respectively) determined by the annealing duration of 0C specimen at 471 °C. Through monitoring of open circuit potential (OCP), measurements of direct-current polarization resistance (PR), Tafel plot (TP), cyclic anodic potentiodynamic polarization (CAPD), and electrochemical impedance spectroscopy (EIS), we found that the corrosion behavior of the Zr48Cu36Al8Ag8 was detremined by the the crystal phase present in the specemns dominated by the annealing durations. The corrosion resistance decreased in the order: 25C > 11C > 0C > 50C > 75C > 100C. This result revealed that the corrosion resistance inclined to be better and reached a mxmium with increasing the percentgae of the crystal phase from 0 to 25%; however, it decreased with further increasing the crystal phase over 25%. A corrosion mechanism is proposed to rationalize the sequence of corrosion resistance. According to the mechanism, the remained free volume and residual strain energy are responsible for the specimens containing crystal phase less than 25% (i.e., 0C, 11C and 25C); whereas crystal defects such as grain boundaries governed the corrosion of those containing crystal phase more than 25 % (i.e., 50C, 75C and 100C).

Influence of processing technology on electrochemical corrosion behavior of Ti-6Al-4V alloys

CORROSION ◽  
10.5006/3490 ◽  
2021 ◽  
Author(s):  
Caiyun Bai ◽  
Peifeng Li ◽  
Tieqiang Gang ◽  
Jian Li ◽  
Min Wei ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Electrochemical Impedance Spectra ◽  
Transfer Resistance ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors ◽  
3D Printed

Ti-6Al-4V alloys are typically used for biomedical implants, aerospace components and offshore equipment, where corrosion resistance is critical. In the present paper, the electrochemical corrosion behaviors of Ti-6Al-4V alloys made by different traditional processing and 3D printing technologies in seawater, 3.5 wt.% NaCl, 3.5 wt.% HCl, 5 wt.% HCl and 10 wt.% HCl solutions were studied through polarization curve and electrochemical impedance spectra (EIS) analyses. The influences of microstructure and printing parameters on the corrosion behaviors of Ti-6Al-4V alloys were analyzed. In addition, the corrosion current density, film resistance and charge transfer resistance of traditionally processed Ti-6Al-4V and 3D printed Ti-6Al-4V in the five solutions were compared. The results show that Ti-6Al-4V possesses a better corrosion resistance in seawater than in 3.5 wt.% NaCl, and that the corrosion rate increases with the HCl concentration. Besides, 3D printed Ti-6Al-4V shows a higher corrosion rate in comparison with traditionally processed Ti-6Al-4V because pores are effortless to enrich Cl-. Finally, the ratio of laser power to its scanning speed and the phase constituent composition of the alloy have slight influences on its electrochemical corrosion behavior. It is suggested that for the 3D printed alloy, the deterioration of mechanical properties induced by corrosion damage during servicing should be assessed and considered.

scholarly journals Electrochemical Investigations of Steels in Seawater Sea Sand Concrete Environments

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5713
Author(s):  
Xiang Yu ◽  
Saad Al-Saadi ◽  
Xiao-Ling Zhao ◽  
R. K. Singh Raman
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Detrimental Effect ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Electrochemical Corrosion ◽  
Chloride Content ◽  
Open Circuit ◽  
Portland Cement Concrete ◽  
Sea Sand

Seawater and sea sand concrete (SWSSC) is an environmentally friendly alternative to ordinary Portland cement concrete for civil construction. However, the detrimental effect of high chloride content of SWSSC on the corrosion resistance of steel reinforcement is a concern. This study undertook the electrochemical corrosion behaviour and surface characterizations of a mild steel and two stainless steels (AISI type 304 and 316) in various simulated concrete environments, including the alkaline + chloride environment (i.e., SWSSC). Open circuit potential (OCP), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were employed. Though chloride is detrimental to the corrosion resistance of mild steels, a simultaneous presence of high alkalinity in SWSSC negate the detrimental effect of chloride. In the case of stainless steels, a high level of alkalinity is found to be detrimental, whereas chloride seems to have less detrimental effect on their corrosion resistance.

Application of EIS and SEM to Study the Corrosion Behaviors of Organic Coatings/Substrate System

2008 ◽  
Vol 373-374 ◽  
pp. 556-559 ◽  
Author(s):  
Rui Yan ◽  
Hang Wu ◽  
S.K. Yu ◽  
Shi Ning Ma ◽  
Bin Shi Xu
Keyword(s):  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Electrochemical Corrosion ◽  
Metal Substrate ◽  
Open Circuit ◽  
Free Corrosion Potential ◽  
Cross Linkage ◽  
Sem Micrograph ◽  
Corrosion Behaviors

Electrochemical corrosion behaviors of two common-used ship coatings——epoxy aluminum coating, chloride rubber iron red coating and their composite coatings immersed in 3.5%NaCl solution were investigated using electrochemical impedance spectroscopy combined with open circuit potential measurements and SEM micrograph analysis. Potential-time result indicates that the free corrosion potential of these three coatings with immersion time are more positive than that of metal substrate, which can serve as barrier layer to protect metal substrate from corrosion. During the course of immersion, increasingly negative shift potentials with time reveal the growth of electrochemical area of anode and corrosion takes place continuously. EIS shows that corrosive species can penetrate into coatings and reach the coating/substrate interface promptly, causing the decrease of its shielding role and the beginning of electrochemical corrosion. SEM micrographs suggest that coatings were compact and continuous compared with obviously coarse and loose after corrosion, indicating the penetration of corrosive species destroys cross linkage of coatings. Composite coatings present better protection performance, displaying the effect of “1+1>2” remarkably.

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