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The utilization of aluminum dross in concrete structures is anticipated to significantly increase concrete structures' mechanical and electrochemical properties. In this present works, the effects of the fraction of aluminum dross on the corrosion kinetics and corrosion resistance of concrete after 30, 60, and 90 days chloride ion exposure were investigated. The electrochemical corrosion behavior of concrete was characterized by potentiodynamic polarization and electrochemical impedance spectroscopy. The interrelation between the fraction of aluminum dross and concrete after 30, 60, and 90 days chloride ion exposure shows that concrete structures with aluminum dross up to 8% exhibit long-term higher corrosion resistance than unmodified concrete. The aluminum dross fraction in concrete structures affects chloride ion composition in concrete structures. [ABSTRACT FROM AUTHOR]

The content of aluminum dross is anticipated to be blended with calcium silicate cement paste to form a gel compound which forms a blocking effect on chloride ion penetration. The effect of aluminum dross on the corrosion resistance of the concrete matrix in chloride solution was characterized by potentiodynamic polarization and electrochemical impedance spectroscopy. X-ray fluorescence was provided to investigate the chloride content of the concrete matrix. It was found that the addition of aluminum dross up to 8% significantly enhance the impedance and passivation range of the concrete matrix. Concrete matrix with alumina dross exhibits more excellent corrosion resistance compared to unmodified concrete matrix. The results demonstrate that a concrete matrix with alumina dross is promising for enhancing the corrosion resistance of the concrete matrix. [ABSTRACT FROM AUTHOR]

Aluminum dross has a low aluminum metal content, so it may be served in making concrete. The addition of aluminum dross is expected to improve the concrete passive layer, contributing to corrosion control. This research investigates corrosion behavior of reinforced bar embedded in concrete with aluminum-added in the immerse condition by seawater. The impact of chloride ion exposure on the reinforced bar will be characterized by electrochemical impedance spectroscopy and potentiodynamic polarization. The microstructure evolution due to time exposure and chloride ion content could be explored by scanning electron microscope. Corrosion resistance on the reinforced bar tends to increase with aluminum dross presence. The consequences demonstrate the significant influence of aluminum dross on the passivation area and corrosion behavior of concrete. [ABSTRACT FROM AUTHOR]

This paper presents a Root Cause Failure analysis for tubing API 5CT Grade J55 leakage on the well conductor. The tubing was installed in oil Well production with gas lift process and found leaked after three years in service. The leakage was reported as multiple leakages after performing an inspection. The investigation has been completed on leaked well tubing. The material conformity confirmed that the tubing material is J55 grade according to API 5 CT. Analysis on the failure mode revealed that the tubing leakage is caused by CO2 corrosion as a result of high CO2 partial pressure in the Well tubing which in the range of 7 to 30 psi at a depth range of 237.4 feet to 1818.1 feet and over 30 psi at a depth above 1818.1 feet. The CO2 corrosion is reported high because the water cut increases during the operation from 2016 to 2018. The dissolved carbon dioxide caused damage on the ID surface of the tubing in the form of pitting and mesa type attack. The Damage is also contributed by the flow inside the tubing where it is reported that the flow regime is slug where large gas bubble creates high shear stress and vibration to the tubing. This effect accelerates the metal loss where localized attach by CO2 corrosion occurs. The inclination of the tubing in well also contributes to the preferential damage on the tubing. [ABSTRACT FROM AUTHOR]

Corrosion caused by carbon dioxide (CO2) on carbon steel pipes and oil and gas processing-equipment is common. Water-soluble CO2 produces carbonic acid (H2CO3) which has more corrosive properties than hydrochloric acid (HCL) at the same pH. Electrochemical impedance spectroscopy and linear polarization resistance were employed to determine the processes occurring during the adsorbed inhibition process on the metal surface. Imidazoline based inhibitor concentration variations helped uncover the ability of inhibitor inhibition and the passivation strength of the formed layer. This research was conducted on A106 Grade. B carbon steel in an environment of 3 % NaCl. The imidazoline based inhibitor concentration varies from 0 to 40 ppm at 40 ℃. At a temperature of 40 ℃ and without inhibitor, the corrosion rate showed 143.6 MPY, but dropped drastically to 22.4 MPY when 5 ppm inhibitor was added. Electrochemical Impedance Spectroscopy was applied to study the inhibition mechanism. It was found that based on an adsorption isotherm analysis, chemisorption happened between inhibitor and metal. [ABSTRACT FROM AUTHOR]

The annealing treatment influence on microstructure evolution and pitting corrosion resistance of UNS S32760 super duplex stainless steel’s repeated welds were investigated. The microstructure evolution was observed through a microstructure characterization and ferrite volume fraction measurement, while pitting corrosion resistance was measured by cyclic potentiodynamic polarization. The results reveal that the original weld (OW) indicates a significant imbalance of ferrite-austenite fractions and a presence of intermetallic phase that was declining the pitting corrosion resistance. On the contrary, after 1100 ºC annealing the specimens of once-repeated weld (HR1), twice-repeated weld (HR2), and three-time-repeated weld (HR3), the balance among ferrite-austenite fractions gradually restores and the intermetallic phase declines, that was improving the pitting corrosion resistance. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the effect of sodium citrate as an additive on the grain size of nickel electroplating SPCC steel. For this purpose, nickel were deposited by direct current electrodeposition from a Watts bath at the current density of 6 A/dm² with adding different amount of sodium citrate (5, 15, 30, 45, 60 g/L). X-ray diffraction (XRD) was used to determine the average gain size of the nickel coatings. Effect of adding sodium citrate on nickel electroplating on hardness, corrosion resistance, and adhesive strength were also investigated by Vickers Hardness, salt spray test, and bending test. The smallest grain size was obtained with grain size 36.8 nm with adding 45 g/L sodium citrate. The hardest nickel deposit was 701 HV with presence of sodium citrate complex in the deposit. Corrosion resistance and adhesive strength were increased by adding sodium citrate in the nickel electroplating bath. [ABSTRACT FROM AUTHOR]

The effect of saccharin on the reduction of crystallite size and nickel electroplating properties was investigated. There are some techniques to obtain nanocrystalline coating and to reduce crystallite size in electrodeposition such as current density, mode of electrodeposition, and organic additive, one of which is saccharin. This charges of 0, 0.5, 1.0, 5.0, 10 g/l saccharin, air agitation, current density 6 A/dm², and with electrolyte solution generally used in nickel electroplating industry is Watts nickel solution. The crystallite size of nickel plating was examined by X-Ray Diffraction, coating thickness was examined by thickness meter, hardness of plating were examined by Vickers hardness, corrosion rate was examined by salt spray test, and adhesive strength was examined by heat and quench test. From the result, it was found that the lowest crystallite size was obtained at 35 nm (10 g/L saccharin), the highest hardness was obtained at 593 HV (10 g/L), the best corrosive level is obtained in grade 8 which is 0.1% (0, 5, 10 g/L saccharin) of the corroded area, and the best adhesive level is obtained no blister in the surface (0, 5, 10 g/L). The increasing number of saccharin given will lead to decreasing crystallite size of plating and corrosion rate, and also will lead to the increasing hardness and adhesive strength. [ABSTRACT FROM AUTHOR]

The purpose of this research is to evaluate the corrosion process which occurs on the water side of Heat Recovery Steam Generator (HRSG) superheater tube. The tube was 13CrMo44 and divided into 3 types of specimen: new tube, used tube (with oxide layer on surface), cleaned-used tube (without oxide layer on surface). The evaluation of corrosion parameters wasperformed using deaerated ultra-high purity water (boiler feed water) in two methods of testing: Tafel polarization and Electrochemical Impedance Spectroscopy (EIS). Tafel polarization was excellent as its capability to show the value of corrosion current and the corrosion rate explicitly, on the other hand, EIS was excellent as its capability to explain for corrosion mechanism on metal interface in detail. Both methods showed that the increase of electrolyte temperature from 25°C to 55°C would increase the corrosion rate with the mechanism of decreasing polarization resistance due to thinning out the passive film thickness and enlarge the area of reduction reaction of cathode. Magnetite oxide scale which is laid on the surface of used tube specimen shows protective nature to reduce the corrosion rate, and clear up this oxide would increase the corrosion rate back as new tube. [ABSTRACT FROM AUTHOR]

In this study, the synthesis of reduced graphene oxide-silver nanoparticles (rGO-AgNPs) was carried out simultaneously by reducing graphene oxide and silver salts. The synthesized nanocomposites were successfully characterized by using UV-vis spectroscopy, X-ray diffraction, and scanning electron microscope (SEM). Methyl Orange dye was used to study the adsorption efficiency of rGO-AgNPs nanocomposites. Parameters affecting the adsorption rate such as the effect of time and pH were investigated. The results showed that the rGO-AgNPs composite was effective in absorbing dyes of methyl orange for 3 hours with a degradation percentage of 15%. [ABSTRACT FROM AUTHOR]