Use of Innovative Gel Electrolytes for Electrochemical Corrosion Measurements on Carbon and Galvanized Steel Surfaces

CORROSION ◽  
10.5006/3309 ◽  
2019 ◽  
Vol 75 (12) ◽  
pp. 1502-1512 ◽  
Author(s):  
Gleidys Monrrabal ◽  
Asuncion Bautista ◽  
Francisco Velasco

This work analyzes the feasibility of using gel electrolytes in portable cells to easily perform electrochemical corrosion measurements on carbon steel and galvanized steel components. A gel manufactured from glycerol and agar, with chlorides and optimized conductivity, has been selected for this study. This gel is easily adaptable to nonflat surfaces and has no risk of crevice corrosion interferences during the measurements. Polarization and electrochemical impedance spectroscopy measurements have been performed with a portable cell with a gel electrolyte. The results have been compared to those obtained in a liquid electrolyte with the same saline composition. The effect of using gel electrolytes on the development of the anodic and cathodic processes when the metal surfaces corrode actively has been analyzed in depth. The changes on the composition of outer oxides due to the gel exposure have also been studied by x-ray photospectroscopy to achieve a better understanding of the results. The gel electrolyte has proved to be an adequate medium for obtaining relevant information about the corrosion performance of active carbon and galvanized steel, although it has a somewhat lower aggressiveness than the liquid electrolyte with the same saline composition.

MRS Advances ◽  
2018 ◽  
Vol 3 (22) ◽  
pp. 1261-1267 ◽  
Author(s):  
Belqasem Aljafari ◽  
Arash Takshi

ABSTRACTRecently, gel polymer electrolytes (GPEs) have been drawn noteworthy attention for different applications, specifically, for supercapacitors. GPEs could become an excellent substitute to liquid electrolytes (LEs) for making flexible and more durable devices. The performance of two different electrolytes (GPEs and LEs) in multi-wall carbon nanotube based supercapacitors were investigated. In spite of significantly lower conductivity of GPEs than LEs, devices with the gel electrolyte presented a superior performance. More focused has been given in this work on demonstrating the performance of supercapacitors based on GPEs and LEs at different concentrations of the acids ranging from 1M to 3M. Both electrolytes have been characterized at room temperature by making supercapacitors and using cyclic voltammetry, charging-discharging, electrochemical impedance spectroscopy, and leakage tests. The experimental results showed that GPE devices had much better capacitances and resistances compare to the LE based devices. Moreover, the capacitances of all devices were increased proportionally with the increase in the concentration from 1M to 3M, and the resistances were increased inversely with the decreased of concentration. The promising results from the gel electrolytes is encouraging for further development of flexible and high capacitance energy storage devices.


2013 ◽  
Vol 750-752 ◽  
pp. 2017-2020
Author(s):  
Wan Qiu Zhou ◽  
Yan Rong Liu ◽  
Jian Wang ◽  
Li Sheng ◽  
Shi Wei Wu ◽  
...  

Molybdate-phosphate conversion coating was prepared by adding addition agent towards molybdenum-phosphorus compounds based bath on comercial hot dip galvanized steel. The anti-corrosion performance of the coating was evaluated by electrochemical technique in 3.5%NaCl. It is found that the anodic branch of polarization curves presented in passivation character. Electrochemical impedance spectroscopy (EIS) results indicate that the radius of the capacity impedance for molybdate-phosphate film increased distinctly with pH decrease, which validate the excellent anti-corrosion performance of the film. The surface morphologies were observed using scanning electron microscopy (SEM), and the results show that the surface of hot dip galvanized steel is covered by a spiculate and floccule shape conversion coating. The chemical composition of the surface coating was investigated by energy dispersive X-ray (EDX), which illustrate that the conversion coating is composed of zinc,oxygen, phosphor and molybdenum.


2013 ◽  
Vol 773 ◽  
pp. 429-434
Author(s):  
Wan Qiu Zhou ◽  
Jian Wang ◽  
Li Sheng ◽  
Yan Hong Kang ◽  
Shi Gang Xin ◽  
...  

A non-chromate conversion coating was prepared from molybdate based bath on the surface of Zn-5%Al hot dip galvanized steel. The influence of the preparation conditions such as temperature, bath pH and treating time on the corrosion resistance of the obtained conversion coating was investigated. The corrosion performance of the film was researched using electrochemical technique in 3.5%NaCl. The results indicate that the anodic branch of the polarization curves present in passivation character. Electrochemical impedance spectroscopy (EIS) illustrate that the radius of the capacity impedance for conversion coating varies distinctly according to the preparation condition. The surface morphology was observed using scanning electron microscopy (SEM), and the results show that the surface of Zn-5%Al hot dip galvanized steel present in eutectic feature after conversion coating treatment. The chemical composition of the coating was detected by energy dispersive X-ray (EDX), and the results illustrate that the conversion coating is composed of Zn, Al , O, P and Mo.


2011 ◽  
Vol 415-417 ◽  
pp. 1806-1809
Author(s):  
Dong Ping Wei ◽  
Sheng Fu Wu ◽  
Zeng Wei Huang ◽  
Shao Mei Ma ◽  
An Ping Liao ◽  
...  

A new synthesis method namely hydrolysis precipitation was used to prepare Zn3(PO4)2•4H2O. Structural characteristics of products were investigated by X-ray Diffraction, scanning electron microscope and chemical analysis. The electrochemical corrosion inhibitions of title zinc phosphate were studied by electrochemical impedance of coating immersion test. The results show that the obtained product is a highly crystalline, micronized and lamellar Zn3(PO4)2•4H2O. Comparing with commercial zinc phosphate, the synthesized lamellar microcrystalline product has excellent anticorrosive property and dispersibility.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shuan Liu ◽  
Huyuan Sun ◽  
Ning Zhang ◽  
Lijuan Sun

The corrosion performance of galvanized steel in closed rusty seawater (CRS) was investigated using weight loss, Tafel polarization curve, and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were carried out for morphological and chemical characterization of the rust layer absorbed on the zinc coating. Effects of temperature and hydrostatic pressure on corrosion resistance of galvanized steel were studied. Results indicated that rust layer could induce pitting corrosion on the zinc coating under the Cl−erosion; high temperature accelerated the corrosion rate of zinc coating and inhibited the absorption of rust layer; the polarization resistance (Rp) of galvanized steel increased with the increase of hydrostatic pressure in CRS.


2020 ◽  
Author(s):  
Nicholas H. Bashian ◽  
Mateusz Zuba ◽  
Ahamed Irshad, ◽  
Shona Becwar ◽  
Julija Vinckeviciute ◽  
...  

<div>We report the successful electrochemical intercalation of F-ions into a densely packed perovskite oxide from a liquid electrolyte at room temperature. Using galvanostatic oxidation and electrochemical impedance spectroscopy coupled with operando X-ray diffraction, we show that roughly 0.5 equivalents of F-ions can be inserted onto the vacant A-site of the perovskite ReO3. Density functional theory calculations indicate that the intercalated phase is thermodynamically unfavorable compared to other less densely packed polymorphs of ReO3F. Pairing X-ray spectroscopy, neutron total scattering measurements, and magic-angle spinning 19F NMR confirms a rapid decomposition of the product on removal from the cell but nevertheless, these results clearly demonstrate that small anions like fluoride can be intercalated into solids as readily as alkali cations at room temperature, which opens new opportunities to electrochemically fluorinate many new materials.</div>


Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 833 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Zhanping Zhang ◽  
Kejiao Li

Waterborne silicate composite coatings were prepared to replace existing solvent-based coatings for ships. A series of complex coatings were prepared by adding anticorrosive pigments to the silicate resin. Adhesion, pencil hardness, and impact resistance were investigated, and corrosion performance in 3.5% NaCl solution was measured by electrochemical impedance spectroscopy (EIS). The results show that adhesion and impact resistance are high, and that pencil hardness can reach 4H. The curing mechanism for the coatings were investigated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanism of curing reaction in the studied waterborne silicate paint was found to be different from that reported in the literature. When the coatings were immersed in 3.5% NaCl solution for 8 h, there is only one time constant in the Bode plot, and coating capacitance (Qc) gradually increases while coating resistance (Rc) gradually decreases. Glass flake composite coatings have better corrosion resistance by comprehensive comparison of Qc and Rc.


2016 ◽  
Vol 23 (02) ◽  
pp. 1550111 ◽  
Author(s):  
JIBO JIANG ◽  
CHENQI FENG ◽  
WEI QIAN ◽  
LIBIN YU ◽  
FENGYING YE ◽  
...  

The electrodeposition of Ni–nano-Cr2O3 composite coatings was studied in electrolyte containing different contents of Cr2O3 nanoparticles (Cr2O3 NPs) on mild steel surfaces. Some techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness, the potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS) were used to compare pure Ni coatings and Ni–nano-Cr2O3 composite coatings. The results show that the incorporation of Cr2O3 NPs resulted in an increase of hardness and corrosion resistance, and the maximum microhardness of Ni-nano-Cr2O3 composite coatings reaches about 495 HV. The coatings exhibit an active-passive transition and relatively large impedance values. Moreover, the effect of Cr2O3 NPs on Ni electrocrystallization is also investigated by cyclic voltammetry (CV) and EIS spectroscopy, which demonstrates that the nature of Ni-based composite coatings changes attributes to Cr2O3 NPs by offering more nucleation sites and less charge transfer resistance.


2018 ◽  
Vol 18 ◽  
pp. 19-26
Author(s):  
Nadjette Belhamra ◽  
Abd Raouf Boulebtina ◽  
Khadidja Belassadi ◽  
Abdelouahed Chala ◽  
Malika Diafi

The purpose of this paper was to investigate the effect of Al2O3 and TiO2 nanoparticles contents on structural proporties, microhardness and corrosion resistance of Zn-Ni alloy coationg. Zn-Ni, Zn-Ni-Al2O3 and Zn-Ni-TiO2 composite coatings were electrodeposited on steel substrate by direct current in sulphate bath.The structure of the coatings was studied by X-ray diffration and by scaning electron miroscopy. The results showed the appearance of Ni5Zn21 phases and that the incrorporation of Al2O3 and TiO2 in the Zn-Ni coating refined the crystal grain size.The corrosion performance of coating in the 0.6M NaCl as a corrisive solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy EIS methods. It was found that the incorporation of nanoparticules in Zn-Ni alloy coating have better corrosion resistance and the values of Rct and Zw increase, while the values of Cdl decrease with increasing of nanoparticules.


2010 ◽  
Vol 636-637 ◽  
pp. 1042-1046
Author(s):  
Magdalena Popczyk ◽  
Antoni Budniok

Zn-Ni and Zn-Ni-W coatings were prepared by the electrodeposition under the galvanostatic conditions (jdep. = -0.020 A cm-2) from the zinc bath containing additionally ions of nickel (Zn-Ni) and ions of nickel and tungsten (Zn-Ni-W). The Zn-Ni coating after electrodeposition was subjected to outside passivation and in the Zn-Ni-W coating the passive function performs tungsten (inside passivation). The surface morphology of the coatings was studied using a scanning electron microscope (JEOL JSM - 6480). Chemical composition of obtained coatings was determined by the X-ray fluorescence spectroscopy (XRF). Phase composition investigations were conducted by X-ray diffraction method using a Philips diffractometer. Electrochemical corrosion resistance investigations were carried out in the 3% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that Zn-Ni coating is more corrosion resistant than the Zn-Ni-W coating.


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