Polarization Resistance Values Research Articles

Alternating current oxidation of Ti–6Al–4V alloy in oxalic acid for corrosion resistant surface finishing

In this work, alternating current (AC) voltage (VAC) is applied to Ti–6Al–4V alloy in aqueous oxalic acid dihydrate solution to grow passive oxide films. The oxide layers are formed with VAC values in the range of 10–80 V. The resulting surface oxide layers have estimated thicknesses in the 100–500 nm range and are expected to have a two-layer structure consisting of a porous outer layer and a compact inner layer. The AC anodization process is demonstrated to have a slight effect on the surface roughness. Porous regions are observed on the films formed at lower and high AC voltages (i.e., VAC 10–30 and 80 V). The corrosion behavior in Ringer’s solution over 48 h of exposure is studied with electrochemical impedance spectroscopy. The AC anodized samples have higher impedance values than the untreated alloy by more than an order of magnitude. The oxides formed at VAC = 40 − 70 V exhibit optimal resistance to corrosion as demonstrated by the overall impedance values, the polarization resistance values, and the capacitive behavior.

Tailoring La2-XAXNi1-YBYO4+δ cathode performance by simultaneous A and B doping for IT-SOFC

The present work focuses on the study of different Ruddlesden-Popper based cathode materials for Solid Oxide Fuel Cells at Intermediate Temperature (IT-SOFC). The partial substitution of La and Ni by Pr and Co, respectively, were studied in the La2-XPrXNi1-YCoYO4+δ system, with the purpose of enhancing their mixed ionic-electronic conductivity and the electrocatalytic activity for the O2-reduction while the crystal structure was preserved. All synthesized compounds were characterized by electrochemical impedance spectroscopy (EIS), DC conductivity measurements, X-Ray diffraction (XRD), iodometric titration and scanning electron microscopy (SEM). XRD analyses by Rietveld refinement revealed the influence of the ionic radius on the crystalline phase for the different dopants, i.e., variation of the cell parameters and M−O bond lengths. The substitution in both La and Ni sites improves La2NiO4+δ electrochemical properties as IT-SOFC cathode, since higher conductivity and lower polarization resistance were obtained. Finally, La1.5Pr0.5Ni0.8Co0.2O4+δ cathode exhibited the lowest electrode polarization resistance and activation energy values in the temperature range of 450–900 °C. La1.5Pr0.5Ni0.8Co0.2O4+δ was applied on an anode supported cell and a maximum power density of ~400 mW cm−2 was obtained at 700 °C using pure hydrogen and air.

Electrochemical performance of Sn-doped Bi0.5Sr0.5FeO3- perovskite as cathode electrocatalyst for solid oxide fuel cells

Abstract The Sn-doped Bi0.5Sr0.5FeO3-δ (BSF)-based perovskite oxide is evaluated as novel cathode electrocatalyst for intermediate-temperature solid oxide fuel cells (IT-SOFCs). In particular, the effects of 10 mol% Sn substitution on phase evolution, thermal expansion behavior and electrochemical performance of Bi0.5Sr0.5Fe0.9Sn0.1O3-δ (BSFSn) material are systematically investigated. BSFSn crystallizes in cubic perovskite structure with space group Pm-3m. Sn doping is found to decrease the average thermal expansion coefficient (TEC) from 14.7 × 10−6 K−1 (BSF) to 12.9 × 10−6 K−1 (BSFSn) within a temperature range of 50–800 °C, due to the enlarged metal-oxygen (Sn-O) bond energy in BSFSn. The X-ray photoelectron spectroscopy (XPS) result proves that Sn doping promotes the oxygen adsorption ability on BSFSn surface. Consequently, the ORR activity of BSFSn is improved as expected. The polarization resistance (Rp) value of BSFSn cathode is 0.09 Ω cm2 at 700 °C in air, which is lower than BSF. The cathode overpotential is 35.6 mV at a current density of 140.8 mA cm−2 at 700 °C in air. The peak power density of the anode-supported cell reaches 960 mW cm−2 at 700 °C. Furthermore, the relationship between oxygen partial pressure and Rp demonstrates that oxygen surface adsorption-desorption is a major rate-limiting step for oxygen reduction reaction (ORR) process on BSFSn cathode. These attractive electrochemical properties suggest that BSFSn oxide is a promising potential cathode electrocatalyst for SOFCs.

Fabrication on designing of a macromolecular epoxy resin as anti-corrosive coating material for electrocatalytically deposited cadmium on 15CDV6 steel in 3% NaCl solution

Present study deliberates for the surface treatment of15CDV6 steel using electrolytic cadmium and its corrosion resistance behavior by a macromolecular epoxy coating (DGEBA-DAA) using computational and experimental techniques. Electrochemical results demonstrated that presence of the cadmium enhances the interfacial adhesion behavior of the DGEBA-DAA and same conclusion was reinforced through the computational studies carried out by means of density functional theory (DFT) and molecular dynamic (MD) simulations methods. EIS studies conducted at several time intervals varying from 1h to 180 days showed that increase in immersion time results into the corresponding decrease in the corrosion resistance behavior of DGEBA-DAA coating as significant decrease in the values of charge transfer resistance (Rct) and polarization resistance (Rp) were observed on increasing the immersion time. DGEBA-DAA coating showed the highest Rct and Rp values of 6.61kΩcm2 and 13.52kΩcm2, respectively after 1h immersion time whereas the lowest Rct and Rp values of 1.07kΩcm2 and 1.80kΩcm2 were obsrved after 180 days immersion . Scanning electron microscopy (SEM) analysis coupled with energy dispersive spectroscopy (EDS) showed that increase in the immersion of 15CDV6 steel in electrolyte decreases the corrosion resistance of the DGEBA-DAA coating through the development, deepening and broadening of the micro-pores. DFT study indicated that DGEBA-DAA interacts through charge transfer (donor–acceptor) interactions in which polar functional groups act as sites for the interactions (adsorption). Outcomes of MD simulations studies depicted that DGEBA-DAA, adsorbed on the cadmium (Cd) surface using its flat or nearly flat orientation thereby acts as effective anti-corrosive coating material. Results of EIS, SEM-EDS, DFT and MDS analyses were in good agreement.

Study of oxygen electrode reactions on symmetrical porous SrTi0.30Fe0.70O3-δ electrodes on Ce0.8Gd0.2O1.9 electrolyte at 800 °C–500 °C

Iron doped strontium titanates (SrTi1-xFexO3-δ) are an interesting mixed ionic-electronic conductor model used to study basic oxygen reduction/oxidation reactions. In this work, we performed an impedance spectroscopy study on symmetrical porous SrTi0.30Fe0.70O3-δ (STF70) electrodes on a ceria-based electrolyte. The sample was measured in varying oxygen concentration: from 0.3% to 100% in 800 °C–500 °C temperature range. Low polarisation resistance (e.g. <125 mΩ cm2 at 600 °C in the air) values were obtained, showing an overall high performance of the STF70 electrode. Impedance data analysis was assisted by the distribution of relaxation times method, which allowed an equivalent electrical circuit to be proposed comprising of two resistance/constant phase element sub-circuits connected in series. The medium frequency contribution, with a characteristic frequency of ∼2000 Hz at 800 °C in air, originates most probably from possible surface diffusion followed by charge transfer reaction limitation, whereas the lower frequency contribution (characteristic frequency <10 Hz) is due to gas-phase diffusion.

Electrochemical properties of aluminum tripolyphosphate modified chemically bonded phosphate ceramic anticorrosion coating

An inorganic coating, combining chemically bonded phosphate ceramic (CBPC) binder and aluminum tripolyphosphate (ATP) pigment, was designed and prepared for anti-corrosion treatment of steel. An electrochemical method was proposed to characterize and evaluate the corrosive behavior of the coating, and the influence of ATP contents associated with XRD and SEM/EDS techniques. The experimental results showed that the addition of the ATP pigment increased the corrosion potential and reduced the corrosion current density, porosity, and water absorption of a coating. Moreover, the polarization resistance (Rp) values were more than twice those of CBPC binder when the ATP was added. The best anti-corrosion profile of the coating was observed when the content of ATP pigment was 15%, which exhibited the least negative corrosion potential (Ecorr) and Rp and smallest corrosion current (Icorr). SEM-EDS results indicate that ATP exhibited more metal ion chelating power than the CBPC binder itself, which shows the better interfacial binding ability. The said coating cannot only provide excellent physical protection but form passivation layer on the surface of a steel substrate to protect it and prevent further corrosion.

Copper Corrosion Behavior in Simulated Concrete-Pore Solutions

The copper corrosion was studied for 30 days in two alkaline electrolytes: saturated Ca(OH)2 and cement extract, employed to simulate concrete-pore environments. Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry were carried out at the open circuit potential (OCP), and potentiodynamic polarization (PDP) curves were performed for comparative purposes. Electrochemical current fluctuations, considered as electrochemical noise (EN), were employed as non-destructive methods. The tests revealed that sat. Ca(OH)2 is the less aggressive to the Cu surface, mainly because of the lower in one order pH. In consequence, the OCP values of Cu were more positive, the polarization resistance values were higher by one order of magnitude, and the anodic currents of Cu were lower than those in the cement extract. The analyzed EN indicated that the initial corrosion attacks on the Cu surface are quasi-uniform, resulting from the stationary persistent corrosion process occurring in both model solutions. XPS analysis and X-ray diffraction (XRD) patterns revealed that in sat. Ca(OH)2, a Cu2O/CuO corrosion layer was formed, which effectively protects the metallic Cu-surface. We present evidence for the sequential oxidation of Cu to the (+1) and (+2) species, its impact on the corrosion layer, and also its protective properties.

Effect of IR Drop on Reinforced Concrete Corrosion Measurements

The ohmic voltage drop (IR) due to the high resistivity of concrete needs to be considered while monitoring the corrosion performance of rebar embedded in concrete. It helps to evaluate the corrosion condition precisely. Concrete mixes were contaminated with chlorides, sulphates, and a combination of chloride plus sulphate solutions as mix water. To assess the IR drop error in corrosion measurements caused by concrete with different salts, linear polarization resistance values were measured with and without IR compensation. The results indicate that the concrete contaminated with 5% of chloride has shown higher error as compared to 2% of sulphates, due to high corrosion current density. However, from the results of chloride and chloride plus sulphate contaminated concrete, it is also confirmed that the IR drop error is not absolute to determine the solution resistance. The higher corrosion in chloride contaminated concrete as compared to chloride plus sulphate contaminated concrete is also observed due to the availability of high chloride concentration. The results of the present study are suggested that the IR drop compensation should be considered when the reinforced structures are exposed to chloride and sulphate environment.

Design and characterization of apatite La9.8Si5.7Mg0.3O26±δ-based micro-tubular solid oxide fuel cells

In this study, electrolyte-supported (Cell A) and anode-supported (Cell B) micro-tubular solid oxide fuel cells (SOFCs) based on the La9.8Si5.7Mg0.3O26±δ (LSMO) electrolyte is built through an extrusion and dip-coating processes. The formulations and process conditions for these cells are established and optimized. Both cell configurations show no visible delamination or cracking, and reaction zones and inter-diffusion of any species are absent at the interfaces of the multilayer structures. The micro-tubes LSMO and LSMO-NiO have a high flexural strength of ~70 MPa. Cell B with a 3.33 mm outer diameter, a 12 μm LSMO electrolyte layer, a ~300 μm LSMO-NiO functional anode layer, a 9 μm NiO current-collector layer, and a 44 μm La0.6Sr0.4Co0.2Fe0.8O3-δ cathode layer has superior electrochemical performances than does Cell A. The polarization resistance (Rp) value for Cell B accounts for 67.6% and 50.5% of the total resistance (Rt) value at 700 °C and 895 °C, respectively, suggesting that Rp dominates at low temperatures and ohmic resistance (Ro) and Rp values are equally important at high temperatures. Cell B's open-circuit voltages (OCVs) are slightly below the theoretical value due to poor sealing of cells. The maximum power densities (MPDs) of Cell B, increase with increasing operating temperature and are 0.12, 0.24, and 0.27 W cm−2 at 750 °C, 850 °C, and 895 °C, respectively. Compared to Cell A, Cell B displays lower OCV values but higher MPD (0.27 W cm−2 vs. 0.06 W cm−2 at 895 °C) due to its significantly lower Ro value, mainly due to the thin layer of LSMO electrolytes.

Electrode performance of La2NiO4+δ cathodes in contact with La0.9Sr0.1ScO3−δ proton-conducting oxide

Ruddlesden-Popper-structured La2NiO4+δ oxide has been applied for the first time as the cathode for La0.9Sr0.1ScO3−δ proton-conducting oxide. The chemical compatibility of the electrode and electrolyte materials has been studied. Electrode performance has been investigated by means of impedance spectroscopy in dry and wet air conditions in the temperature range of 600–800 °C. Real polarization resistance values were calculated taking into account the shunt effect of electronic hole conductivity in the electrolyte.

In-situ growth of nanoparticles-decorated double perovskite electrode materials for symmetrical solid oxide cells

The development of symmetrical solid oxide fuel cells (SSOFCs) can accelerate the commercialization of SOFCs because it can reduce the fabrication cost, improve the thermomechanical compatibility between the electrolyte and electrodes, and enhance the ability of resisting coking and sulfur poisoning. In addition, it is more convenient to switch between the SOFC mode and the solid oxide electrolysis cell (SOEC) mode for the SSOFCs. In this work, we report a new family of double perovskite symmetrical electrodes Sr2Ti1–xCoxFeO6 (x = 0, 0.1, 0.2, 0.3, STCF) for SSOFCs. The Sr2Ti0.8Co0.2FeO6 (STC02 F) electrode can be exsoluted with the cobalt-iron alloy nanoparticles and can maintain the double perovskite structure in reducing atmosphere. The STC02 F electrode also has good chemical compatibility with La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte. The polarization resistance (Rp) values of the STC02F-based symmetrical cells are 0.124 and 0.380 Ω cm2 at 800 °C in air and in hydrogen, respectively. The output power densities of the single cell with the configuration STC02 F/LSGM (270 μm)/STC02 F reach 555, 180, 404, and 390 mW cm–2 at 800 °C using H2, liquefied petroleum gas, C2H5OH, and CH3OH, respectively. Moreover, the symmetrical cell with STC02 F electrode shows good electrochemical performance and stability for the electrolysis of H2O or CO2 and co-electrolysis of H2O/CO2 at intermediate temperatures for SOECs.

Surface modification and electrochemical properties of cobalt-based layered perovskite cathodes for intermediate-temperature solid oxide fuel cells

PrBaCo2−xCuxO5+δ (0 ≤ x ≤ 0.2, PBCCO) layered perovskite materials were studied as cathode materials for low-temperature solid oxide fuel cells. The electrical conductivity of PBCCO decreased with an increase in Cu content, and PrBaCo1.8Cu0.2O5+δ (PBCCO20) showed the lowest electrical conductivity of 570 S cm−1 at 750 °C. In order to enhance the kinetics of the oxygen reduction reaction on the surface of PBCCO, Au-decorated PBCCO (Au@PBCCO) having gold nanoparticles on their surface was prepared by sputtering. The TEM-EDS analysis confirmed that gold nanoparticles were uniformly formed on the surface of PBCCO. Cu ions on the PBCCO surface bond with the Au nanoparticles, serving as anchors to maintain the nanoscale particle size even after heat treatment at high temperature. The Au@PBCCO showed a 60% lower polarization resistance value at 700 °C than that of the PBCCO20 due to enhanced ORR activity. We hypothesize that this enhancement is due to the fact that the electron transfer to the surface of PBCCO by the gold nanoparticles is promoted and the reduction of oxygen adsorbed on the surface increased.

Corrosion Behavior of TiN/CrN Nanoscale Multi-layered Coating in Ringer's Solution

In this article, corrosion behavior of the single-layered TiN, single-layered CrN and multi-layered TiN/CrN coatings have been fabricated on 420C stainless steel (SS) by Cathodic Arc Evaporation (CAE) method in Ringer's solution was studied. The electrochemical appraisal was done by the Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) tests. Results of PDP test revealed that all coated specimens have an increment in the polarization resistance (Rp) values (ranges from 438.2 to 593.6Ω.cm2) compared to bare SS (268.1Ω.cm2). Corrosion rate values for bare 420C SS and CrN, TiN and multi-layered TiN/CrN coatings were measured 0.086, 0.042, 0.050 and 0.068mpy, respectively. Furthermore, EIS results were showed that the single-layer CrN coating well depicted by an equivalent circuit with three time constants and has larger impedance and maximum logarithmic variation of C2. Finally, the corrosion performance results confirmed that single-layered CrN coating is an appropriate choice for deposition on 420C SS with the aim of application in general surgical instruments.

Highly durable macromolecular epoxy resin as anticorrosive coating material for carbon steel in 3% NaCl: Computational supported experimental studies

AbstractThe purpose of present study is in the direction of development of an anticorrosive coating formulation of high durability for carbon steel corrosion in 3 wt% NaCl medium. The formulation comprises of a macromolecular epoxy coating (DGEDDS‐MDA) based bisphenol S diglycidyl ether (DGEDDS) cured with a methylene dianiline (MDA). The formulation was characterized by FT‐IR spectroscopy method. Performance of the epoxy coating was represented using PDP and EIS approaches. The formulation acts as effective anticorrosive coating for long durability (180 days). Surfaces of the specimens before and after 180 days exposure to UV radiation were examined using SEM. PDP, SEM, and EIS studies showed that DGEDDS‐MDA acted as highly durable and effective anticorrosive formulation. Results also showed that the formulation acts as interface type inhibitor and its presence enhances the polarization resistance (Rp) value. DFT study suggests that the formulation DGEDDS‐MDA possesses strong ability to interact with metal surface through its several electron rich centers. MD and MC simulations showed that studied formulation effectively adsorb on the substrate (metallic surface). Results of EIS, PDP, and SEM studies (experimental) were well‐supported by DFT, MD, and MC (computational) simulations.

Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Andrographis paniculata

An aqueous extract of Andrographis paniculata has been used as corrosion inhibitor, in controlling corrosion of mild steel in simulated oil well water (SOWW). Weight loss method reveals that 10 mL of the extract offers 94% inhibition efficiency to mild steel immersed in simulated oil well water (SOWW). The mechanistic aspects of corrosion inhibition have been investigated by electrochemical studies such as polarization study and AC impedance spectra. Polarisation study reveals that the inhibitor system controls the cathodic reaction predominantly as revealed by the shift of the corrosion potential to the cathodic side in presence of the inhibitor system. The corrosion protective nature of the inhibitor is confirmed by the increase in the linear polarization resistance value and decrease in the corrosion current value. The formation of a protective film on the metal surface is confirmed by the AC impedance spectra. This is confirmed by the fact that there is increase in charge transfer resistance value and decrease in double layer capacitance value. The adsorption of the inhibitor molecule obeys Langmuir adsorption isotherm. The protective film has been analyzed FTIR spectra. It confirms that the inhibitor has coordinated with ferrous ion the metal surface through the polar atoms of the inhibitor molecule. The surface morphology of the protective film has been investigated by SEM and AFM. It is observed that in presence of inhibitor the surface of the corroded metal becomes smoother. The Vickers hardness of the metal surface before experimentation and after experimentation has been measured. It is observed that the surface becomes harder in presence of inhibitor than in the absence of inhibitor under the influence of corrosive medium, namely simulated oil well water. The findings have potential application in petroleum industry. The inhibitor extract can be added along with the simulated oil well water in the pipelines made of mild steel.

Assessment of Nd1.5Pr0.5Ni1−xMxO4+δ (M = Cu, Co, Mo; x = 0, 0.05 and 0.1) as cathode materials for intermediate-temperature solid oxide fuel cell

This work presents study of the doping effect of M = Cu, Co, and Mo on the cathode properties of Nd1.5Pr0.5Ni1−xMxO4+δ. In particular, four compositions are prepared by a modified sol–gel method, e.g., Nd1.5Pr0.5NiO4+δ (NPN), Nd1.5Pr0.5Ni0.9Cu0.1O4+δ (NPNCu), Nd1.5Pr0.5Ni0.9Co0.1O4+δ (NPNCo), and Nd1.5Pr0.5Ni0.95Mo0.05O4+δ (NPNMo). The crystal structure, phase stability, electrical conductivity, thermal expansion coefficient (TEC), and electrochemical performance of the oxides are systematically investigated. No chemical reactions between NPN, NPNCu, NPNCo, and NPNMo cathodes and Ce0.8Sm0.2O1.9 electrolyte are found. The average TEC values of the NPN, NPNCu, NPNCo, and NPNMo are determined to be 13.9 × 10−6 K−1, 13.6 × 10−6 K−1, 14.7 × 10−6 K−1, and 13.2 × 10−6 K−1 in the range of 30–1000 °C, close to that of the typical electrolyte materials. NPN and NPNCu cathodes exhibit very low interfacial polarization resistance value of 0.033 and 0.032 Ω cm2 at 800 °C, which translates to superior fuel cell performance, e.g., peak power density of 456 and 443 mW cm−2, respectively. The electrochemical performance, however, could be significantly degraded by the Co and Mo doping in the Ni site. The presented results demonstrate that NPN and NPNCu are promising cathode candidate for intermediate-temperature solid oxide fuel cells.

Optimization of sintering temperature for SOFCs by a co-firing method

A single-step co-firing process is employed to fabricate solid oxide fuel cells (SOFCs) with an Sm-doped CeO2 (SDC) electrolyte, aiming to simplify the SOFC fabrication procedure. Complete tri layer green cells are co-fired in a single step at different fabrication temperatures, and the co-firing temperature significantly influences the cell microstructure and thus influences its performance. Electrochemical investigations indicate that the cell resistance, including the ohmic and polarization resistance, varies with the co-firing temperatures used and leads to a different cell power output. Although the cell polarization resistance follows the rule that higher firing temperatures lead to higher polarization resistance values, the cell ohmic resistance does not follow the expectation that the cell fired at 1200 °C gives the largest ohmic resistance. The morphology analysis reveals the mechanism behind this phenomenon. The best cell performance is obtained by co-firing the cell at 1000 °C, reaching 401 mW cm−2 at 700 °C.

Effect of Recycled PET (Polyethylene Terephthalate) on the Electrochemical Properties of Rebar in Concrete

This research is focused on the use of recycled PET (Polyethylene terephthalate) as an aggregate to improve the electrochemical properties of reinforcing steel in concrete. Samples were made with different PET geometries such as: fibers (F), rectangles (R), and mixture of fiber and rectangle (F–R). The PET was added as a substitute for sand with a PET/sand ratio by volume percent of 3%/97%, 5%/95%, and 8%/92%. Specimens were exposed to an aggressive solution of sodium chloride at 3%, simulating a marine environment, and were evaluated for 300 days through various electrochemical techniques such as: open-circuit potential, electrochemical noise, electrochemical impedance spectroscopy, and linear polarization resistance. Samples with PET reached more noble values of potential compared to the control sample. The highest values of noise resistance (Rn) and polarization resistance (Rp) were reached for the reinforcing steel in concrete samples prepared with particle of rectangles and fiber–rectangle mix. Likewise, these samples maintained a diffusive behavior for a longer time. At the end of the test period, the favorable effect of the rectangles and the mixture of fibers and rectangles in the concrete samples are evident, since they remain in the negligible range of corrosion rate, with values below 1 × 10−1 μA/cm2. This behavior was not noticeable for samples with only PET fibers, due to the fact that they reach the moderate range of corrosion rate, with values between 2 × 10−1 and 5 × 10−1 μA/cm2, similar to the control sample.

Cobalt-free perovskite Ln0.5Sr0.5Fe0.8Cu0.2O3-δ (Ln = Pr, Nd, Sm, and Gd) as cathode for intermediate-temperature solid oxide fuel cell

Ln0.5Sr0.5Fe0.8Cu0.2O3-δ (LnSFC, Ln = Pr, Nd, Sm, Gd) perovskite oxide as a cobalt-free cathode was systematically evaluated for intermediate-temperature solid oxide fuel cell (IT-SOFC). XRD results show that PrSFC presents the cubic structure, while NdSFC, SmSFC, and GdSFC present an orthorhombic structure. The conductivity of the four samples is in accordance with the GdSFC < SmSFC < NdSFC < PrSFC relationship. AC impedance testing was performed using a symmetrical fuel cell of the structure LnSFC/Ce0.9Sm0.1O1.95(SDC)/LnSFC. The polarization resistance values of PrSFC, NdSFC, SmSFC, and GdSFC are 0.036, 0.089, 0.097, and 0.160 Ω cm2 at 800 °C, respectively. Then, SDC electrolyte-support single cell was fabricated and the power densities of PrSFC, NdSFC, SmSFC, and GdSFC cathodes were 364, 311, 254 and 104 mW cm−2, respectively, at 800 °C. Our preliminary experiment results show that LnSFC oxide meets the requirements of the electrode, and it can be a possible cathode for IT-SOFC.

Corrosion behavior of hybrid coconut shell powder and silica carbide reinforced aluminium composite towards aggressive biofilm attack

This study enveloped innovative uses of a hybrid agro waste and silica carbide incorporated with aluminium as a new hybrid composite materials for marine application. In this study, the purpose of adding coconut shell powder (CSP) from the agro waste and silicon carbide (SiC) as reinforcement aluminium composites materials for combating corrosion problem. The CSP was incorporated into the molten aluminium alloys varies from 0%, 5%, 10%, 15% and 20% of weight percentages. The corrosion behaviour was determined by weight gain measurement (WGM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). As a results, 5% CSP reinforcement in hybrid aluminum composites contribute to excellent corrosion resistance performance by shifting the polarization curve towards the positive region, increases the value of polarization resistance, Rp and reduces the Icorr value. It can be concluded that, by adding CSP into aluminium composite has significantly increase the corrosion resistance towards a severe biofilm attack.