The formation process of Zr-doped silane film on carbon steel during immersing in Zr(NO3)4/silane mixed solutions

2017 ◽  
Vol 64 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Xiaochao Xian ◽  
Chenglong Nai ◽  
Lixin Li ◽  
Shuo Zhao

Purpose Immersion is one of the key steps during the preparation of silane-based hybrid films, which has important effects on the performance of films after curing. In this paper, the formation process of Zr-doped silane film (i.e. the adsorption of silane and deposition of zirconium compounds) on carbon steel immersed in Zr(NO3)4/silane mixed solutions was investigated. Design/methodology/approach The method of in situ monitoring the open circuit potential of a two-electrode system, consisting of carbon steel and saturated calomel electrode, was used. The effects of immersion conditions (i.e. the concentration of Zr(NO3)4 and pH of Zr(NO3)4/silane mixed solution) on the open circuit potential were investigated in detail. Furthermore, the surface coverage rate of different cured films (i.e. Zr cured film, silane cured film and Zr/silane composite cured film) after curing on carbon steel was calculated according to the results of polarization curves. Electrochemical impedance spectroscopy (EIS) was used to study the self-healing property of Zr-doped silane cured film. Findings The results indicate that in Zr(NO3)4/silane mixed solutions, most zirconium compounds deposit on the surface of carbon steel at the initial immersing stage, then the adsorption of silane on the residual surface of carbon steel dominates the following immersing stage. EIS results show that the Zr-doped cured film has improved self-healing property. Originality/value First, the method of in situ monitoring the open-circuit potential of two-electrode system was applied to investigate the deposition of Zr and the adsorption of silane on carbon steel immersed in Zr(NO3)4/silane mixed solutions. Second, the formation process of Zr-doped silane film was proposed.

2021 ◽  
Vol 2 (108) ◽  
pp. 68-74
Author(s):  
M. Ali ◽  
J.H. Mohmmed ◽  
A.A. Zainulabdeen

Purpose: This work aimed at evaluating the properties of the ethyl silicate-based coating that can be applied on low carbon steel. Design/methodology/approach: Two mixture ratio types (2:1, and 3:2) of resin and hardener respectively were used to prepared two specimen models (A and B). Findings: It found that some mechanical properties (tensile, hardness, and impact strength) of ethyl silicate resin were evaluated according to standard criteria. Research limitations/implications: The effect of heat treatments at various temperatures (100, 150, and 200°C) and holding at different times (10, 20 & 30) min on hardness was investigated. Practical implications: Moreover, an open circuit potential corrosion test with a solution of 3.5% Sodium Chloride at room temperature and 60°C was used to determine the corrosion resistance of low carbon steel specimens coated with the two mixture types. Originality/value: The effects of mixture ratios (for resin and hardener) and heat treatment conditions on properties of ethyl silicate-based coating were studied. From obtained results, acceptable values of tensile, hardness, and toughness were recorded. Increasing heat treatment temperature and holding time leads to enhance hardness for both model types. An open circuit potential (OCP) tests show that there is an enhancement of protective properties of ethyl silicate coatings with mixture type B in comparison with type A was achieved. Generally, the results indicate that specimen model B has higher properties as compared with specimen model A.


2019 ◽  
Vol 9 (4) ◽  
pp. 706 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and corrosion morphology in-situ capturing using an optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with a scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After completion of the signal processing, including pre-treatment, shape preserving interpolation, and denoising, for raw AE waveforms, three types of AE signals were classified in the correlation diagrams of the new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.


2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Pravin Deshpande ◽  
Sanket Vathare ◽  
Shashikant Vagge ◽  
Elena Tomšík ◽  
Jaroslav Stejskal

AbstractThe coaxial coating of multi-wall carbon nanotubes (MWCNT) with poly(aniline) (PANI) was synthesised and a paint was prepared containing conducting PANI-MWCNT composite. The corrosion protection performance was assessed by open circuit potential measurements, potentiodynamic polarisation, and electrochemical impedance spectroscopy. The corrosion rate of low-carbon steel coated with 1.5 mass % of PANI-MWCNT-based paint in 3.5 mass % sodium chloride solution was found to be 0.037 mm y−1, about 5.2 times lower than that of unpainted low-carbon steel and 3.6 times lower than that of epoxy painted steel.


2014 ◽  
Vol 805 ◽  
pp. 167-171 ◽  
Author(s):  
F.S. Silva ◽  
P.H. Suegama ◽  
W.P. Silva ◽  
A.W. Rinaldi ◽  
N.L.C. Domingues ◽  
...  

Schiff bases m-toluene N-Salicylideneaniline (m-TOL), (B) m-nitro-N- Salicylideneaniline (m-NTR) and (C) m-methoxy-N-salicylideneaniline (m-MTX) and cerium ions were studied added to 3.5 wt.% NaCl solution and added to the hybrid film based tetraethoxysilane (TEOS) e 3-methacryloxypropyltrimethoxysilane (MPTS). The polarization measurements showed lower current densities for the steel in NaCl with m-MTX, indicating that the m-MTX may be acting as an inhibitor. The hybrid films were doped with the m-MTX, Ce (III) or Ce (IV). Electrochemical measurements of open circuit potential (EOC), polarization curves and electrochemical impedance spectroscopy (EIS), were used to evaluate the corrosion behavior of the hybrid films. According Electrochemical Impedance measurements, all hybrid films, provided protection to the carbon steel. The films doped with Ce (IV), provided greater protection than the other, which indicates that this is the most suitable dopant for use in films.


2021 ◽  
Vol 37 (2) ◽  
pp. 433-439
Author(s):  
L. Sutha ◽  
A. Cyril

In this work, GeO2 (germanium dioxide) and Sc2O3 (scandium trioxide) were developed as coatings on AZ31 alloy using polymer binder. The coatings were characterized using X-ray crystallography procedure (XRD), infrared spectrum of absorption or emission of a solid procedure (FTIR), Raman spectroscopy procedure, surface examination by FESEM. The corrosion studies were analyzed using a three electrode system in 3.5% NaCl electrolyte. The bare AZ31 alloy showed open circuit potential (Ecorr) of -1.7 V (SCE) and the corrosion current density (icorr) of 3.4 x 10-4 mA/cm2, while the Sc2O3 coated AZ31 alloy exhibited Ecorr of -1.4 V (SCE) and the icorr of 5.4 x 10-9 mA/cm2 and while the GeO2 coated AZ31 alloy exhibited Ecorr of -1.3 V (SCE) and the icorr of 2.59 x 10-9 mA/cm2. The results reveal that the GeO2 coated AZ31 alloy demonstrated higher corrosion resistance than of bare AZ31 alloy and Sc2O3 coated AZ31 alloy.


2017 ◽  
Vol 64 (6) ◽  
pp. 644-653 ◽  
Author(s):  
A.U. Chaudhry ◽  
Vikas Mittal ◽  
M.I. Hashmi ◽  
Brajendra Mishra

Purpose Inorganic oxide addition can be synergistically beneficial in organic coatings if it can impart anti-corrosion properties and also act as an additive to enhance physical and/or chemical properties. The aim of this study was to evaluate the anti-corrosion benefits of nano nickel zinc ferrite (NZF) in the polymer film. Design/methodology/approach The time-dependent anti-corrosion ability of NZF (0.12-1.0 per cent w/w NZF/binder), applied on API 5L X-80 carbon steel, was characterized by electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic. Characterization of corrosion layer was done by removing coatings after 216 h of immersion in 3.5 per cent w/v NaCl. Optical microscopy, field emission scanning electron microscopy and X-ray diffraction techniques were used to characterize the corroded surface. Findings Corrosion measurements confirm the electrochemical activity by metallic cations on the steel surface during corrosion process which results in improvement of anti-corrosion properties of steel. Moreover, surface techniques show compact corrosion layer coatings and presence of different metallic oxide phases for nanocomposite coatings. Originality/value The suggested protection mechanism was explained by the leaching and precipitation of metallic ion on the corroded surface which in turn slowed down the corrosion activity. Furthermore, improvement in barrier properties of rubber-based coatings was confirmed by the enhanced pore resistance. This work indicates that along with a wide range of applications of NZF, anti-corrosion properties can be taken as an addition.


2020 ◽  
Author(s):  
Junhua Dong

<p>In the multi-barrier system of HLW repository, overpack is the first barrier to isolate high-level radioactive nuclides from biosphere, and Low carbon steel has been considered to be a promising candidate material for manufacturing the oberpack due to its good mechanical performance and workability and weldability. However, during thousands of years of geological disposal, the corrosion resistance of low carbon steel and its corrosion evolution behavior are the first element that must be fully understood, because it determines the life cycle of the artificial barrier.</p><p>Conventional studies had suggested that the corrosion of low carbon steel under the deep geological environment was driven by hydrogen evolution reaction (HER) based on that the dissolved oxygen was completely depleted during the long term disposal. However, the residual oxygen content is a critical factor to determine the corrosion mode of cathodic reduction reaction. Thermodynamics data indicated that the initial ferrous corrosion products formed in the deaerated bicarbonate solution can be chemically oxidized into ferric substance by the trace content of dissolved oxygen, and the accumulated FeOOH as a cathodic depolarizer significantly increased the open circuit potential and enhanced the corrosion rate of the low carbon steel. Moreover, chloride and sulfate in the simulated groundwater can reduce the increase of open circuit potential but it still promotes the corrosion of the low carbon steel. As the environments contained aggressive anions and high concentration of dissolved oxygen, low carbon steel was prone to suffer from the localized corrosion and the corrosion rate was obviously increased. By alloying with some contents of Ni and Cu, the corrosion rate of low alloy steel was decreased by an order of magnitude and it was less prone to suffer from the localized corrosion.</p><p>Under the conditions of simulated groundwater with different content of GMZ bentonite,the bentonite colloidal particle layer attached to the surface of low carbon steel showed blocking effect on resisting oxygen diffusion to the steel substrate, which consequently decrease the further oxidation of ferrous to ferric substances and the corrosion rate of low carbon steel. However, the barrier performance of bentonite colloids would be deteriorated due to their coagulation caused by the ferrous ions dissolved from the steel substrate. High content of bentonite was beneficial to maintain and to prolong the stabilization of the barrier system. An equivalent circuit model which correlates with the interfacial structure between electrode substrate and rust and bentonite layer was proposed. The fitting results showed a very good match between the model and experimental data, and the evolution of the results was also in agreement with real changes.</p>


2014 ◽  
Vol 896 ◽  
pp. 168-172 ◽  
Author(s):  
Djoko Hadi Prajitno ◽  
Dani Gustaman Syarief

Corrosion of carbon steel in nanofluid containing 0.1 gpl of ZrO2nanoparticle at temperature from 25 to 55°C was investigated by using potentiodynamic polarization techniques. The open circuit potential measurements, cathodic and anodic polarization were used to characterize the corrosion behavior of carbon steel. Metallurgical techniques such as optical microscopy and X-ray diffraction (XRD) were used to characterize the alloys before and after corrosion testing. The microstructures of the as received carbon steel exhibited equaxed morphology. While corrosion specimens showed that microstructure of carbon steel alloys relatively unchanged after polarization testing. X ray diffraction examination of carbon steel before polarization represent γ phase and after polarization is still γ phase with minor Fe2O3. The open circuit potentials of carbon steel increase to positive displacement with increasing temperature nanofluids. The results of polarization technique show that corrosion currents increase and therefore corrosion rates become faster with the increase of nanofluids temperature.


2013 ◽  
Vol 785-786 ◽  
pp. 933-937
Author(s):  
Yi Xiao ◽  
Jian Feng Gu ◽  
Li Bin Yu ◽  
Yi Wang ◽  
Qing Dong Zhong

In this paper, nanoSiO2used to be an accelerator of Zinc phosphatization for electrochemical inhomogeneity in the process of phosphate coatings on carbon steel by wire-beam electrode. The open circuit potential of the phosphated samples was analyzed using average method. The result showed the large influence of nanoSiO2on the nucleation and growth of the phosphate coatings.


2014 ◽  
Vol 61 (6) ◽  
pp. 402-408 ◽  
Author(s):  
Luciana V.R. de Messano ◽  
Leila Y. Reznik ◽  
Lucio Sathler ◽  
Ricardo Coutinho

Purpose – The purpose of this paper was to use the barnacle Amphibalanus amphitrite reared in the laboratory to investigate the effects of juveniles on corrosion behaviour of three stainless steels (SS): UNS S31600, N08904 and UNS S32760. Design/methodology/approach – Barnacle larvae were maintained in a laboratory until they reached the cypris larval stage. A total of 100 cyprids were added to four individual containers; each SS coupon (70 × 50 × 2 mm3) was immersed into the containers. After the cyprids attached to the coupons, juveniles were reared for 21 days with the microalgae Skeletonema costatum (Greville) Cleve. Values of open circuit potential (OCP), breakdown potential (Eb) and polarisation resistance (Rp) were evaluated, along with surface examinations. Findings – OCP differences between barnacles and control coupons were not apparent. However, the lowest values of Eb and Rp were observed in the presence of juvenile barnacles, demonstrating the SS corrosion caused by these organisms. Crevice corrosion around the base of the barnacles was detected during visual inspections, despite the small size of the barnacles and the short duration of the experiments. Originality/value – The A. amphitrite assays were useful as a tool for testing corrosion behaviour of the SS under laboratory conditions. This was the first study to test the use of this common protocol in anti-fouling research as a method to study marine biocorrosion.


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