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Recent Advances in Polymer Nanocomposite Coatings for Corrosion Protection
Published in Mahmood Aliofkhazraei, Advances in Nanostructured Composites, 2019
Subramanyam Kasisomayajula, Niteen Jadhav, Victoria Johnston Gelling
In this category of PNCs, sol-gel method has been extensively used to prepare various PNCs and deposit them on marine steel substrates for corrosion protection evaluation. Among them, TiO2 based sol-gel coatings have become very popular due to their excellent chemical stability, hardness, and barrier properties. Curkovic et al. observed increase in corrosion performance of TiO2 sol-gel coating in 3.5 wt% NaCl solution as the number of layers increases (Ćurković et al. 2013). Cheraghi et al. also noticed similar phenomenon in the case of TiO2-NiO nanocomposite preparation process (Cheraghi et al. 2012). Significant reduction in corrosion current density was noticed with the number of layers (tested up to 6 dipping times) formed on the metal substrate. In addition to TiO2 sol-gel coatings, organically modified sol-gel coatings based on 3-glycidoxypropyltrimethoxysilane (GPTMS) were also effectively implemented for the corrosion protection of stainless steel in marine environments. Further, in order to improve the efficiency of these sol-gel coatings, corrosion inhibitors such as cerium nitrate (Ce(NO)3) were incorporated into them as observed in the work of Zandi Zand et al. (Zandi Zand et al. 2011).
Conducting Polymer Coatings for Corrosion Protection
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Polymer Coatings, 2020
Polymers created from a solution of cerium nitrate exhibit a strong barrier effect. They have a reduced cathodic and anodic current, established in the corrosion current, and increased polarization resistance after 48 and 72 hours of exposure to the corrosive environment, giving clues to this – treatment (self-healing). The release of nitric ions and part of the cations of cerium, which are naturally adsorbed to the polypyrrole coating, contributes to cathodic protection as the intensity of currents in the cathodic part of the polarization curve is significantly reduced. Anodic protection is also present as there is cathodic and anodic current after 72 hours of exposure to sodium chloride solution. The open-potential measurement shows that there is a tendency to stabilize the potential after 24 hours of immersion in the corrosive environment. Using for the formation of the polymer solution of p-TSA coatings show barrier protection for a short immersion time and signs of possible this – treatment in long exposure intervals. The barrier protection that exists in the first hours begins to collapse after 24 hours of exposure to the corrosive environment, as it is concluded comparing the results obtained after 48 hours of exposure. Increasing the anodic current shows signs that the coating is starting to degrade. The anticorrosion properties of the coatings with PPA are similar to those with cerium nitrate. With p-TSA, OA and CSA are created coatings are created with stability that can passivate the surface at the end of time, with little reduction of their protective properties for the last two in long exposure times. For the coating doped with the anion of p-TSA stability is observed at the end of time may be explained by the nature of doping. Compared to nitrates, the anions of p-TSA are larger in size, making the process of releasing them more difficult, so the time of protection of coatings increases. For the coating of a CSA solution, the continuous-current polarization measurements indicate that the coating’s behavior is stable after 48 hours of stay in the corrosive environment, with an increase in the corrosion current after 72 hours. It is important to stress that after 72 hours, the corrosion current did not increase significantly despite the ripples of open potential. Quite stable behavior of coatings is observed in the case of OA without significant alteration of the corrosion properties in long periods of stay in sodium chloride solution. The corrosion current rises and the polarization resistance decreases to 72 hours of exposure. For all coatings, it was found that the release of ion doping is not done immediately by dipping the coating into the sodium chloride solution, but due to the different water uptake process, as shown by the OCP measurements in the first hours of immersion in the sodium chloride solution, the release of the anion is different.
Bimetallic Mn-Ce loaded on different zeolite carriers applied in the toluene abatement in air by non-thermal plasma DDBD reactor
Published in Environmental Technology, 2022
Su Liu, Jiabin Zhou, Dan Liu, Xianjie Liu, Wenbo Liu
The main metal component manganese with a loading of 5%, uses manganese acetate (99.0%, Chron, Chengdu, China) as a precursor; and the auxiliary metal cerium uses cerium nitrate (99.0%, Chron, Chengdu, China) as a precursor with a content of 1%. The bimetallic Mn-Ce supported catalysts were prepared via the wet impregnation method using a certain molecular sieve (Catalyst Co. Ltd. of Nankai University, Tianjin, China) as the carrier. The zeolites were impregnated in a precursor solution of manganese acetate and cerium nitrate of the desired concentration. Following impregnation treatment under slow stirring for 24 h, the impregnated samples were dried in vacuum dryer (Senxin, DZG-6020, China) by temperature-programmed heating and gradually reducing the vacuum to evapourate the solvent. After that, the samples were calcined at 350°C for 5 h. The obtained samples were labelled as Mn-Ce/ZSM-5, Mn-Ce/SZSM-5, Mn-Ce/MCM-41, and Mn-Ce/SBA-15, respectively.
Biofabrication of CeO2 nanoparticles, characterization, photocatalytic, and biological activities
Published in Inorganic and Nano-Metal Chemistry, 2021
R. Bakkiyaraj, Ramasamy Subramanian, M. Balakrishnan, K. Ravichandran
Cerium (III) nitrate hexahydrate (Ce(NO3)3.6H2O (99%)) was purchased from Sigma Aldrich, Bengaluru, India. Dimethyl sulfoxide (DMSO) and methylene blue (MB) were purchased from Loba Chemie, Mumbai, India. Phosphate buffered saline, fetal bovine serum, and penicillin was purchased from HIMEDIA, Mumbai, India. Dulbecco’s modified eagle medium (DMEM), neutral red powder, and trypsin were purchased from MPBIO, USA. Human skin cancer cells A431 was purchased from the National Center for Cell Science, Pune, India. Analytical grade chemicals were used without further purification. Cerium nitrate solution was prepared using double distilled water. The leaves of O. Sanctum were collected from the campus, Government Engineering College, Bargur, Krishnagiri, India.
Effect of γ-irradiation on structural, morphological and luminescence properties of cerium-doped Y3Al5O12 nano-material
Published in Radiation Effects and Defects in Solids, 2019
Allaoua Boukerika, Lakhdar Guerbous
The procedure used for synthesis of YAG: 0.5% Ce3+ phosphor powders are presented in different step. Firstly, stoichiometric Y2O3 was dissolved in 100 mL of de-ionized water, previously mixed with 3 mL of nitric acid (HNO3) and stirred at 80°C for 1 h to yield a clear and homogeneous solution. Secondly, stoichiometric aluminum nitrate was dissolved to the resultant solution at a molar ratio, Y: Al, of 3:5. Then the corresponding stoichiometric of cerium nitrate with 0.5 at. % was added to the solution. Then Acetic acid (AC) was added to the solution with molar ratio AC: M3+ = 1 (M3+: Y3+ + Al3+ + Ce3+), and subsequently ethylene glycol (EG) was added at a molar ratio EG: AC, of 2:1. The solution was continuously stirred for several hours and the pH value of the solution has been stabilized at 1 using ammonia solution (NH4OH). The resulting solution was dried at 120°C until the foam was formed. Finally, the YAG: 0.5%Ce3+ phosphors powders were obtained after annealing the precursors (foam) at 900°C for 2 hours.