Microstructure and Anti-Corrosion Properties of Arc-Sprayed Aluminum Coating in Splash Zone

2011 ◽  
Vol 199-200 ◽  
pp. 1949-1953
Author(s):  
Qing Jun Zhu ◽  
Kai Wang
Keyword(s):  
Aluminum Coating ◽  
Splash Zone ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Aluminum Coatings ◽  
Arc Spray ◽  
Mild Carbon Steel ◽  
Dissolution Zone ◽  
Corrosion Behaviors ◽  
Al Coating

Aluminum coatings were developed by arc spray on mild carbon steel Q235. Scanning electron microscopy detection shows that the coatings have good bonding with the substrate and have low porosity. The corrosion behaviors of the coatings in splash zone were studied. The results show that free corrosion potentials of aluminum coatings are much lower than that of Q235. Potentiodynamic polarization measurements reveal that the curves of aluminum coatings have activity anodic dissolution zone, passivation zone and super-passivation zone. Corrosion morphology and energy dispersive spectrometers show that Cl- can penetrate into the coatings and some of the substrate has been corroded. The arc spray Al-coating develops a film of corrosion products on the coating surface, which tend to seal the pores in the coatings. Arc spray aluminum coatings can protect the substrate from corrosion in splash zone.

Corrosion Behavior of Cold-Spray Aluminum Coating in Marine Environment

2010 ◽  
Vol 160-162 ◽  
pp. 364-368
Author(s):  
Qing Jun Zhu ◽  
Kai Wang ◽  
Xin Hong Wang
Keyword(s):  
Cold Spray ◽  
Marine Environment ◽  
Aluminum Coating ◽  
Corrosion Morphology ◽  
Aluminum Coatings ◽  
Mild Carbon Steel ◽  
Dissolution Zone ◽  
Bond Zone ◽  
Corrosion Behaviors ◽  
Scanning Electron

Aluminum coatings were prepared by cold spray on mild carbon steel Q235. Scanning electron microscopy shows that the bond zone has good bonding between the substrate and the coating and the coatings consist of interlocked particles. The corrosion behaviors of the coatings in marine environment were studied by electrochemical methods. Free corrosion potentials of aluminum coatings are much lower than that of Q235. Potentiodynamic polarization measurements show that the curves of aluminum coatings have activity anodic dissolution zone, passivation zone and super-passivation zone. Corrosion morphology and energy dispersive spectrometers show that Cl- can penetrate into the coating and some of the substrate has been corroded. Corrosion only can happen on the coating surface and specific deeper sites, where Cl- can penetrate through pores. Cold spray aluminum coatings can protect the substrate from corrosion in marine environment.

Research on Corrosion-Resistance of High Velocity Arc Spray Coatings on Surface of Steel Structure in Splash Zone Environment

2011 ◽  
Vol 675-677 ◽  
pp. 1291-1294 ◽  
Author(s):  
Shi Cheng Wei ◽  
Bin Shi Xu ◽  
Xiu Bing Liang ◽  
Yu Jiang Wang ◽  
Yi Liu
Keyword(s):  
High Velocity ◽  
Steel Structure ◽  
Steel Structures ◽  
Arc Spraying ◽  
Splash Zone ◽  
Factors Affecting ◽  
Spray Coatings ◽  
Arc Spray ◽  
Before And After ◽  
Corrosion Behaviors

The most severe corrosion of offshore steel structure occurs in splash zone. There are many factors affecting the steel structure corrosion in the splash zone, such as corrosion problems caused by seawater and effect of impacted brought by the ocean wave. Considering the corrosion characteristics in splash zone and the corrosion invalidity behaviors of offshore steel structure, the Zn-15Al, Al-RE, Zn-Al-Mg-RE and FeBSiNb uncrystal coatings were prepared by automatic high velocity arc spraying. The different anti-corrosion behaviors of the four coatings were studied through the corrosion comparative tests and the microstructures analyzed of the coatings before and after the corrosion tests. The anti-corrosion coating systems suitable for using on surface of steel structure corrosion in the splash zone were found, which provided technique guarantee for extending the using life of offshore steel structures.

Corrosion Properties of Arc Spray Zn-25Al and Zn-50Al Coating in Marine Environment

2011 ◽  
Vol 239-242 ◽  
pp. 1215-1218
Author(s):  
Qing Jun Zhu ◽  
Kai Wang
Keyword(s):  
Electrochemical Impedance ◽  
Impedance Spectrum ◽  
Electrochemical Impedance Spectrum ◽  
Natural Seawater ◽  
Corrosion Properties ◽  
Arc Spray ◽  
Seawater Corrosion ◽  
Capacitive Loop ◽  
Corrosion Behaviors ◽  
Protection Potential

Zn-25Al and Zn-50Al coatings were prepared by arc spray in mild carbon steel Q235. The corrosion behaviors of these coatings were studied by potentiodynamic polarization test in natural seawater, corrosion potentials and electrochemical impedance spectrum. The results show that the Ecorr of Zn-25Alcoating is -1.025V (SCE) and the Ecorr of Zn-50Al coating is -0.997V (SCE) at the beginning of the immersion. The Ecorr of the Zn-50Al coating is not stable as the Zn-25Al coating. Self-corrosion potential of Zn-25Al coating is lower than Zn-50Al coating. Zn-25Al can provide lower protection potential and promising current to protect the substrate from corrosion than Zn-50Al. The EIS of these two coatings reveal single capacitive loop. The anti-corrosion properties of Zn-25Al coatings are better than that of Zn-50Al coatings.

Corrosion Behaviors of Mg-7Gd-5Y-1Nd-0.5Zr Alloys in CO2 Atmosphere under Different Relative Humidity

2014 ◽  
Vol 900 ◽  
pp. 39-42
Author(s):  
Quan Tong Jiang ◽  
Xing Gang Li ◽  
Yong Jun Li ◽  
Ming Long Ma ◽  
Guo Liang Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Relative Humidity ◽  
Influence Factors ◽  
Corrosion Morphology ◽  
Corrosion Rates ◽  
Corrosion Behaviors ◽  
Peak Aged ◽  
Residual Mechanical Properties ◽  
Loss Rates

The corrosion behaviors of peak-aged Mg-7Gd-5Y-1Nd-0.5Zr alloys in CO2atmosphere under different relative humidity were investigated by OM, SEM. The weight loss rates, corrosion morphology and residual mechanical properties were also analyzed. The corrosion rates of specimens in CO2atmosphere at 70% relative humidity were highest than others. Relevancy of the influence factors included relative humidity and concentration of CO2were researched. The results show that relative humidity and concentration of CO2in the environment both played an important role in corrosion behaviors.

Influence of various sterilization methods on hardness, grain size and corrosion rate of a Mg6Ag-alloy

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Frank Feyerabend ◽  
Martin Johannisson ◽  
Zhidan Liu ◽  
Regine Willumeit-Römer
Keyword(s):  
Grain Size ◽  
Corrosion Rate ◽  
Optimum Ratio ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Materials Properties ◽  
Physiological Conditions ◽  
Alloying System ◽  
Dry Heat

AbstractSterilization is a necessary step for all implant materials. Different methods can influence the materials properties. Especially important for magnesium as degradable materials is the determination of the corrosion properties. In this study the influence of 70% ethanol, glutaraldehyde, autoclaving, dry heat, UV-, gamma- and electron beam-irradiation on mechanical and corrosion parameters were analyzed. As mechanical parameters hardness and grain size were determined. The corrosion rate under physiological conditions, weight of the corrosion layer and corrosion morphology was determined. It could be demonstrated that irradiation treatments and 70% ethanol are suitable methods, as they decrease the corrosion rate. Heat-introducing methods (autoclaving and dry heat) acted as incomplete ageing treatments on this alloy and therefore increased the corrosion rate. Furthermore, osmolality showed a better correlation to the actual corrosion rate than the pH. Therefore an optimum ratio between alloying system, implant and sterilization method has to be established, depending on the intended application.

Corrosion of the Materials in Sulfuric Acid

2008 ◽  
Author(s):  
Hong Pyo Kim ◽  
Dong-Jin Kim ◽  
Hyuk Chul Kwon ◽  
Ji Yeon Park ◽  
Yong Wan Kim
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Hydrogen Production ◽  
Immersion Time ◽  
Cross Sectional ◽  
Corrosion Morphology ◽  
Nuclear Heat ◽  
Corrosion Behaviors ◽  
Materials Used ◽  
Surface Morphologies

The program for hydrogen production with high temperature nuclear heat has been launched in Korea since 2004. Iodine sulfur (IS) process is one of the promising processes for a hydrogen production because it does not generate a carbon dioxide and massive hydrogen production may be possible. However, the highly corrosive environment of the process is barrier to the application in the industry. Therefore, corrosion behaviors of various materials were evaluated in sulfuric acid to select appropriate materials compatible with the IS process. The materials used in this work were Ni base alloys, Fe-Si alloys, Ta, Au, Pt, Zr, SiC and so on. The test environments were boiling 50wt% sulfuric acid without/with HI as an impurity and 98wt% sulfuric acid. The surface morphologies and cross sectional areas of the corroded materials were examined by using SEM equipped with EDS. From the results of the weight loss and potentiodynamic experiments, it was found that a Si enriched oxide is attributable to a corrosion resistance for materials including Si in boiling 98wt% sulfuric acid. Moreover the passive Si enriched film thickness increased with the immersion time leading to an enhancement of the corrosion resistance. Corrosion behaviours of the material tested are discussed in terms of the chemical composition of the materials, a corrosion morphology and the surface layer’s composition.

Corrosion behaviors of X70 steel under direct current interference

2019 ◽  
Vol 66 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Jun Wang ◽  
Zili Li ◽  
Gan Cui ◽  
JianGuo Liu ◽  
Chuanping Kong ◽  
...  
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Soil Solution ◽  
Direct Current ◽  
Polarization Curves ◽  
Solution Ph ◽  
Corrosion Morphology ◽  
Content Type ◽  
Tafel Polarization ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution. Design/methodology/approach The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy. Findings The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution. Originality/value All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.

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