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Go to Editorial ManagerThe electrodes material plays an important role in the amount of electricity produced in microbial fuel cells (MFCs). Metal electrodes used in MFCs are subject to biological and concentration cell corrosion which leads to a decrease in the cell efficiency. In the present work, the corrosion behavior of three selected electrode materials, namely, stainless steel, copper, and zinc under different operating conditions was investigated and discussed. In anode chamber, the microorganism (MO) used was Saccharomyces cerevisiae (yeast) with sodium acetate as a substrate forming the microbial corrosive solution. In the cathode chamber, the corrosive solution is aerated water. The effects of different operating parameters on the corrosion rate (CR) of these electrodes were studied such as: microorganism concentration, aeration of cathode chamber, and flow velocity in cathode chamber. The potential of the each electrode was measured to understand the corrosion behavior of electrodes and the produced current was also investigated. It was found that the corrosion rate of the electrodes in both anode and cathode chambers increases with increasing MO concentration in anode chamber and with increasing agitation speed in cathode chamber. The bio-corrosion is an important part of the corrosion occurring in microorganism chamber. The stainless steel exhibited the lowest corrosion rate for the whole investigated range of operating parameters followed by copper. The zinc electrode was found to be poor as an electrode in MFC as its corrosion rate was very high in all conditions investigated. In addition, this study showed that the air pumping in water chamber causes an appreciable increase in the corrosion rate in both chambers and an increase in the produced current.
In the present work the effect of Corrosion & Scale Inhibitor was evaluated by using of the commercial product (Kurita S2050) that mainly containing of (Na2HPO4) sodium phosphate as corrosion inhibitor and (C6H11NaO7) sodium glocunate as scale inhibitor & dispersant. The dosing rate of this chemical was controlled according to the treatment system depend mainly on the monitoring of LI & RI indexes for (30) days treatment in the cooling tower unit of Al-Dora Oil refinery-Baghdad. The corrosion rate and the corrosion inhibitors efficiency were calculated by measurement of weight loss in standard test coupon (AISI 1010). After 30 day of the Field Test, the result show that the treatment program performance was effective in the corrosion & scale inhibition through an acceptable corrosion rate less than 0.018 in gmd. Also the result of corrosion rate was analyzed statistically by using of (ANN) to formulate a prediction equation to corrosion rate identification.
The present work deals with direct diffusion bonding welding without interlayer of austenitic stainless steel type AISI 304L with Oxygen Free High Conductivity pure copper (OFHC) in vacuum atmosphere (1.5 *10-5 mbr.). The optimum bonding conditions are temperature of 650 ?C, duration time of 45 min. and the applied stress of 30 MPa, in order to secure a tight contact between the mating surfaces. The corrosion behavior of diffusion bonding joints in 3.5% Nacl is studied to evaluate the corrosion resistance of welding joints by using Potentiodynamic method. The observed microstructure of corroded specimen of optimum diffusion bonding joint shows that the corrosion current density has low value as compared with base materials used. During polarization, galvanic coupling is observed between two materials used. At passivity region, inverse polarity is occurred at 450mV. Therefore, passive stainless steel 304 L behaves as cathode respective to pure copper, the corrosion behavior of the diffusion bonding joint was mostly by copper side. The corrosion results indicate the presence of galvanic effect. The corrosion current density of copper, stainless steel 304L and bond joints condition were (3.66 µA/cm2, 1.62 µA/cm2 and 1.85µA/cm2) respectively. A SEM examination of corroded diffusion bonding joint indicates that the galvanic corrosion happened on copper side. The corrosion rate of bonding joint conditions was 0.85 mpy, which is less than 1%. This means that corrosion resistance of bond joint is more than excellent.
The toxicity of permanent implants is the main concern. The release of ions from the substrate leads to toxicity. Because of how the human body works biologically, the toxicity of corrosion compounds is a byproduct of wear and fretting debris. aimed to improve the corrosion resistance of a 316L stainless steel substrate. Bio ceramic Nano-hydroxyapatite (HA) was coated using the Electrophoretic Deposition (EPD) technique. Stainless steel has good mechanical properties and high compatibility, but it suffers from body fluid attack due to its chloride content, which can penetrate the passivation layer, resulting in the release of chromium and nickel ions. Tissues and organs are damaged by the ions and debris that are released. To address this problem, it was coated with bioceramic using the EPD method. Suspensions of various powders—hydroxyapatite, magnesium oxide, zinc oxide, and the composite—were prepared and coated by electrophoretic deposition. The coated samples were dried at room temperature to ensure a homogeneous coating structure. The zeta potential test for magnesium oxide and hydroxyapatite suspensions was positive, while zinc oxide and complex suspensions were negative. One of the important parameters for achieving electrolyte and implant balance is the open circuit potential (OCP). A substantial change towards a more noble direction (less negative) was seen in the OCP-coated (316 L) alloy, suggesting excellent thermodynamic stability. Tafel extrapolation analysis was used to obtain the corrosion potential (Ecorr) and corrosion current density (Icorr) values of composite-coated stainless steel 316L, which are generally derived from the polarization curve. The findings that are in line with the MgO, HA, and ZnO coatings show a significant decrease in corrosion current (Icorr), an increase in corrosion potential (Ecorr), and a decrease in corrosion rate from (4.386 × 10-¹ mm/y) Stainless Steel 316 L to (1.417 × 10-² mm/y) MgO Coated and (1.222 × 10-³ mm/y) (65%MgO+25%ZnO+10%HA coated).
Galvanic corrosion of Nickel-Chrome alloy (Ni-Cr alloy) and Copper (Cu) coupled in 5% sulfuric acid solution was investigated. The effects of agitation velocity, temperature, and time on the galvanic corrosion current and the weight loss of both metals in both free corrosion and galvanic corrosion were investigated. The trends of open circuit potential (OCP) of each metal and galvanic potential (Eg) of the couple were also determined. The results showed that Cu was cathodic relative to Ni-Cr alloy in galvanic couple and the corrosion potential of the couple (Ni- Cr alloy /Cu) was between the values of the two single components because the OCP of copper shifted to positive with the increase in velocity. Under stagnant conditions initially the galvanic current was more negative then shifted to the positive with time. The corrosion of Ni-Cr alloy decreased with time because the passivation layer was formed on the surface. Under flow conditions, the galvanic current sharply shifted to the negative direction (increase galvanic current from Ni-Cr alloy (anode) to Cu (cathode) during the first few minutes.
The impact of flow velocity (0-900 rpm) on the corrosion rate of carbon steel in a wide range of sulfuric acid concentrations (0-90% in H2O) at 30 °C and 1 h was studied and discussed. In addition, the efficiency of corrosion inhibitor (dimethyl disulfide, DMD) was evaluated in hardest corrosion conditions for the range of velocity investigated. The results revealed that increasing the flow velocity of H2SO4 solution, increases the corrosion rate depending on the acid concentration. When the flow velocity is increased of H2SO4 solution, the corrosion potential was shifted to more negative. The DMD inhibitors showed significant inhibition efficiency at high velocities, where the highest percentage of inhibitor efficiency reached 98% at 900 rpm.
The presence of heavy metal pollutants in refinery effluent significantly impacts the corrosion rate of carbon steel. The focus of this research is to analyze the impact of various inorganic pollutants, including copper, vanadium, nickel, and chromium ions, on the corrosion of carbon steel across different solutions. After conducting a thorough examination of various operating conditions, including pollutant concentration (ranging from 300-3000 ppm), temperature (30-60? C), and flow velocity (0-800 rpm). Our research shows that copper ions have the highest corrosion rate, with vanadium ions being a close second. Conversely, nickel and chromium had the most negligible impact on corrosion rate and, in some instances, even exhibited corrosion inhibition effects. It was also observed that an increase in flow velocity and temperature significantly amplified the corrosion rate of the metal ions investigated.
In this paper, the efficiency of six different types of corrosion inhibitors used in Basrah drinking water tanks was assessed using a potentiostatic test method. The mechanism of adsorption of silicate and phosphate inhibitors in AISI 316 stainless steel surfaces and the effects of different water components in inhibitors are discussed in detail. The values of corrosion rate obtained from the Potentiostatic test showed that the protection against corrosion in the presence of inhibitors is better compared to the case of absence of inhibitors. The results of the six types of corrosion inhibitors tested showed that the inhibitory efficacy is higher below the temperatures 45oC, but when raise the temperature above 45oC the inhibitory efficiency becomes to decrease. Also, the test results indicated that the corrosion inhibitor involves silicate products provided more inhibited efficiency compared to the phosphate inhibitor alone or used the combined silicate/phosphate corrosion inhibitor. The inspection of the surface of the tested samples using optical methods shows that the pitting corrosion is demonstrated on the specimen surfaces after testing with or without inhibitors.
Corrosion in turbine blades may be considered the most crucial problems in power plants. Corrosion may lead to unbalance masses in turbine blades and therefor serious vibration problems. In this study coating nanomaterials namely Al2O3 and TiO2 are used to resist the corrosion. Coatings consist of Al2O3 with 13 wt% TiO2 are generally used to improve the corrosion, erosion and wear resistance. Tests specimens were taken from the portion of turbine blades in Al-Doura station which located in the south of Baghdad. The specimens are divided into two groups, the first group without coating and the second group with nanoparticale coating including alumina (Al2O3) and (Al2O3-13 % wt TiO2), the coating applying by airbrush device using atomization technique with the aid of nitrogen 2 bar pressure . The properties of coated specimens have been investigated by SEM. The SEM showed that the deposition of nanoparticles on the surface of the samples was uniform and homogeneous. The thickness of coated layers was obtained using gravimetric method. Nano alumina with 13% wt of Titanum oxide coating gave the highest thickness 7.1 µm because of agglomeration of these particles comparing with other particales. Electrochemical properties was achieved by corrosion test at 90 ° for 20 min, the properties indicated that the corrosion resistance increased for coated specimens and these properties showed that the nano alumina with 13% wt of nano Titanium oxide was better than other coating and get a protection efficiency equal to 85.56%.
This research deals with the extent to which corrosion affects the behavior of buckling for 6061-T4 aluminum alloy under increasing compressive dynamic loads. Two types of columns, long, and intermediate were used.1% of the length column is the allowable lateral deflection. This is called the critical buckling of the columns. For the purpose of calculating the critical deflection, a digital dial gauge was used and set at a distance of 0.7 of column length from the fixed end condition for the column. The experimental analysis revealed that the corrosion time negatively affects the mechanical properties of materials such as the corroded specimens of 60 days (The least time to observe the corrosion of aluminum in the soil) which have approximately 2.7 % reduction in ultimate strength compared with the non-corroded specimen. Increasing the corrosion time reduces the critical load such as the maximum reduction will be 4.24% in critical buckling load for 60 days’ corrosion time. The results obtained were experimentally compared with the theoretical formulas of the Perry-Robertson and Euler-Johnson formula with the results of the ANSYS. It was found that the Perry-Robertson formula has a good agreement with the experimental results with a safety factor of 1.2, while the Euler-Johnson formula agreed with the experimental results taking a safety factor of 1.5. The ANSYS results showed a good agreement between the measured and calculated values by taking 1.1 factor of safety.
The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.
The corrosion behavior of martensite phase in Cu-Al-Be shape memory alloy with aging at 150 at time 2,4and 6 hour and quenching ice water with salt, water at room temperature and oil media study by open circuit potential, tafal polarization and cyclic polarization. The microstructure of martensite study by optical microscope and x-ray diffraction(XRD) and transformation temperature was determined by Di?erential Scanning Calorimeter (DSC).the result show aging martensite at 150 at 2 and 4 hour have high open circuit potential, low corrosion current density , high corrosion potential and pitting potential than martensite without aging.
In the present work the effect of heat treatment processes at different temperatures and in different quenching media on mechanical properties in addition to corrosion behavior in different pH solutions of aluminum alloy 6061 was achieved.The alloy was received as fabricated and the solution heat treatment processes was achieved at temperatures (490,530,570 °C), then quenching for every degree was done in two media (water, oil) to obtain on six samples. The artificial aging was done on every sample at temperature (160°C) for one hour.The microstructure was examined to show Mg2Si in every sample.The results of hardness test showed that the hardness of alloy increased with increasing heat treatment temperatures, and at the same temperature the quenched specimens in oil had higher hardness.On the other hand, the tension tests showed that the strength of alloy increased with increasing of heat treatment temperature, and at the same temperature the quenched specimens in water had higher hardness.The results of corrosions test showed that the heat treatment operations improved corrosion resistance, and the lower value was get upon treating at 530°C.
The microstructural analysis and electrochemical measurements tests were used to investigate the behaviors of (TiO2) and (HAp)-coated Ti-6Al-7Nb alloy in the SBF solution .By using RF sputtering, a thin TiO2 layer coated the substrate, while a thick layer of HAp coated the outer side of surface. The generated middle layer consist of the composite of TiO2 and HAp which is by AFM characterized as uniformly distributed coating system with nano size. The images of the scan electron microscopy (SEM) shows that there is no any cracking observed in the outer layer of tested samples due to the use of thin film TiO2 as mid lead to reduce the difference in the thermal expansion between the HAp material and Ti-6Al-7Nb substrate .The HAp upper layer significantly improve the bioactivity of the Ti-6Al-7Nb alloy. In this study, the bonding strength and the corrosion resistance was improved by using thin layer of TiO2. From electrochemical impedance spectroscopy (EIS) study Bod plot, the composite layer of TiO2 and HAp was suggested by the capacitive act as barrier layer coated substrate and prevent the relays of the ion from metallic. The results shows the values of Rox (309.2 k? cm2)are greater than for Rct(19.2 k? cm2), by assumes the presence oxide film increases for coated substrate are greater than that of uncoated, which is a result of the presence of coated film that improve the corrosion resistance of the sample.
Welding residual stress has influences on fatigue, fracture, and corrosion. It is therefore important to explore the welding factors effect on the residual stresses. In this work, four welding factors (current, arc voltage, welding travel speed and included angle) were used to weld low carbon steel (ASTM A516 Grade 60).The experiments included welding of (60) pieces with dimensions of (300 x 150) mm and 10 mm thickness that were conducted based on the design matrix founded by using design of experiment (DOE) software (DESIGN EXPERT 10) with response surface methodology (RSM) technique. The X-Ray diffraction (XRD) method was used to measure the residual stress, which was then modeled and optimized in terms of the welding factors using (RSM) technique. The data showed that the welding travel speed and arc voltage have a significant influence on the residual stress. It was found that the optimum solution for minimum residual stress was at 450 Amp welding current, 34 volt arc voltage, 38 cpm welding speed, and 60? included angle. Where, the optimum value of residual stress was (-88.4 MPa). Finally, the predicted and experimental results of residual stress were in agreement with a maximum error of 1.8%.
Super-hydrophobic is the tendency of a surface to spit out water droplets. Only a surface with high apparent contact angle (>1500), low contact angle hysteresis (<100), low sliding angle (<50), and strong Cassie model state stability is considered a super-hydrophobic surface. In an attempt to create highly hydrophobic synthetic surfaces suitable for a range of uses, attempts have been made to mimic the super-hydrophobicity found in natural materials (such as lotus leaves). Due to its wide range of applications including waterproof, anti-fog, anti-ice and anti-corrosion surface, the laser processing process achieved the use of process parameters which had a significant impact on the roughness factor. High roughness factor F. At constant values of p = 3 mW and ω = 10 μm, at scanning speeds of 6000 mm/s.
This research is devoted to design and implement a Supervisory Control and Data Acquisition system (SCADA) for monitoring and controlling the corrosion of a carbon steel pipe buried in soil. A smart technique equipped with a microcontroller, a collection of sensors and a communication system was applied to monitor and control the operation of an ICCP process for a carbon steel pipe. The integration of the built hardware, LabVIEW graphical programming and PC interface produces an effective SCADA system for two types of control namely: a Proportional Integral Derivative (PID) that supports a closed loop, and a traditional open loop control. Through this work, under environmental temperature of 30°C, an evaluation and comparison were done for two types of controls tested at low soil moisture (48%) and high soil moisture (80 %) to study the value of current, anode voltage, pipe to soil potential (PSP) and consumed power. The results show an decrease of 59.1% in consumed power when the moisture changes from the low to high level. It was reached that the closed loop controller PID is the best solution in terms of efficiency, reliability, fast response and power consumption.
The traditional electric poles in Iraq are usually made from steel materials. Such materials induced high weight, corrosion, permanent deformation caused by high wind speed, etc. The study aimed to numerically examine the strength of few poles made from different materials. The pole subjected to pressure developed by actual measured wind speed of 140 km/h. The numerical model of different materials and cross sections, an octagonal section electric pole made from composite material FRP–HDPE–FRP is suggested to replace the traditional one. The results showed high safety factor, approximately 5.51 besides the low ratio of high strength to weight as compared to steel materials. Using HDPE as reinforced material resulted in pole elastically deformed with only 0.222 mm. Therefore, it can be assumed that the suggested pole acts partially as a damper. Straight octagonal cross - section of pole promoted high reduction (74.22%) in maximum Von–Misses stress of that obtained in cylindrical three-stage pole. High reduction (5.87 times) in maximum deformation value was obtained when composite octagonal pole was used as compare to tapered pole made from steel.
The separation of water from crude oil emulsions is a critical and complex challenge in petroleum production and processing. Water-in-oil (W/O) emulsions increase viscosity, pose corrosion risks, reduce refining efficiency, and raise significant environmental concerns. Traditional separation methods often struggle with stable emulsions containing small droplets due to limitations in cost, environmental impact, and effectiveness. Electro-coalescence demulsification has emerged as a promising technique that applies electric fields to enhance droplet coalescence, facilitating efficient water removal. This comprehensive review examines the influence of electrode geometry on electro-coalescence systems in depth, synthesizes key findings from numerous studies, and provides a detailed analysis of electrode spacing calculations, critical conditions for effective demulsification, and optimal operational parameters. By exploring these aspects comprehensively, the review offers insights into how electrode design affects demulsification efficiency, guiding future advancements in crude oil processing and contributing to more sustainable practices in the petroleum industry.