scholarly journals Improving the Corrosion Resistance of Tin-bronze by Surface Modification

2021 ◽  
Vol 23 (09) ◽  
pp. 1270-1281
Author(s):  
Mahmoud Abbas ◽  
◽  
Rehab M. El-Maghraby ◽  
Esraa Hassan ◽  
Reda F. M. Elshaarawy ◽  
...  

Bronze alloys are made of copper-based materials with another metal, usually tin. Many surface modification techniques such as chemical etching, oxidation, electro deposition and sol-gel could be employed to improve surface properties. The organic compound that was used in this study was extracted from chili peppers. FT-IR (Fourier-transform infrared) spectroscopy and UV (Ultraviolet) spectroscopy investigations were applied on the extracted compound and results showed that this compound is mainly capsaicin [N-(4-hydroxy-3-methoxybenzyl)-8-methylnon-trans-6-enamide) (HMMTE)]. Electrochemical deposition was employed under cell voltage equal to 30 volts in a two-electrodes cell where bronze was the anode and stainless steel was the cathode in a solution of 10 ml/L (HMMTE)/distilled-water. Modification of tin-bronze for 1 hr. in 10 ml/L HMMTE/ distilled water solution increased the contact angle from 48° to 132˚. Attension Biolin device (Model: Theta Optical Tensiometers) was used to measure the contact angle at ambient temperature. Electrochemical measurements revealed that a significant improvement in corrosion resistance of tin-bronze in 3.5% NaCl had been achieved. The corrosion rate of tin-bronze decreased from 10.22 mpy to 1.39 mpy. Surface morphology of the samples was investigated with scanning electron microscopy (SEN) and energy-dispersive X-ray (EDX). X-ray diffraction was employed to determined present phases. Surface investigations results confirmed that a layer of red cuprous oxide (Cu2O) was formed on the surface layer after modification which led to the improvement in corrosion resistance. Salt spray test was carried out using Alpha+ Salt Spray Testing Equipment for 13 days on the base and surface modified samples according to ASTM B117. A green layer from [CuCl2 and Cu46Cl24(OH)68-(H2O)4] was observed on the nonmodified specimen (could be patina and bronze disease) while the red layer [Cu2O] is still observed on the modified specimen. Adhesion test (using X-Cut Tape Adhesion test according to ASTM D3359) was also investigated.

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 89
Author(s):  
Wei Yuan ◽  
Qian Hu ◽  
Jiao Zhang ◽  
Feng Huang ◽  
Jing Liu

This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2.


2020 ◽  
Vol 984 ◽  
pp. 43-50
Author(s):  
Hua Yuan Zhang ◽  
Can Wang ◽  
Bing Xue ◽  
Jing Luo

To improve the corrosion resistance on Q235 low carbon steel, in this paper, tetraethyl orthosilicate (TEOS), N-dodecyl trimethoxysilane and γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) were used to make organic-inorganic hybrid sol-gel film. Cross cut test adhesion method, neutral salt spray test, electrochemical test and film protective efficiency were taken to value the corrosion resistance property. The corrosion topography was studied by optical microscope. In addition, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) curves and equivalent electric circuit fitting were used to analyze the corrosion mechanism. The cross cut adhesion of sol-gel film can reach 1 class and the protection class can attain 5 class after 72 hours neutral salt spray test. According to the potentiodynamic polarization curve analysis, the corrosion potential of sol-gel film coating sample after 0.5 hours immersion was -0.46 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.74×10-7 A·cm-2. The corrosion potential of bare Q235 low carbon steel plate after 0.5 hours immersion was -0.78 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.75×10-6 A·cm-2. The impedance value on 0.1 Hz (|Z|0.1Hz) (1.27×106 Ω·cm2) of sol-gel film coating sample was more than three orders of magnitude higher than the value of the low carbon steel plate. Even dipping in 3.5 wt. % NaCl for 72 hours, the |Z|0.1Hz value of sol-gel coating sample was still one order of magnitude higher than the low carbon steel plate with 0.5 hours immersion. Sol-gel film with excellent adhesion can significantly improve the corrosion resistance of low carbon steel plate. Sol-gel film can increase the protection efficiency of low carbon steel plate by 90%.


2006 ◽  
Vol 118 ◽  
pp. 209-214
Author(s):  
Yuan Hui Li ◽  
De Fu Luo ◽  
Shao Xu Wu

The QPQ complex salt bath treatment is a type of surface technology which contains mainly salt bath nitriding and post-oxidizing processes. The effect of QPQ oxidizing temperature and duration on the corrosion resistance of QPQ treated specimens has been explored by immersion tests and salt spray tests in this paper. All the specimens were post-oxidized after being nitrided at 570! for 2 hours. The material used in this study were 1020 steel. In the immersion tests, the specimens were immersed in 3‰ H2O2 and 10% NaCl water solution. In the salt spray tests, specimens were salt spray tested using 5% NaCl neutral solution. From the experimental data, for high corrosion resistance, conclusions can be drawn:(1) appropriate temperature should be selected carefully in post-oxidizing stage .Too low or too high temperature would decrease the corrosion resistance. (2) The best post-oxidizing duration should generate magnetite film in porous area and should not collapse. (3) In second oxidizing stage, the porous area has been partly eliminated, so the duration should be less than the duration of post-oxidizing.


1999 ◽  
Vol 576 ◽  
Author(s):  
T. L. Metroke ◽  
R. L. Parkhill ◽  
E. T. Knobbe

ABSTRACT1H-13C and 1H- 29Si CP/MAS NMR spectroscopy has been used to characterize the structure of sol-gel derived hybrid materials prepared from 3-glycidoxypropyltrimethoxysilane (GLYMO) and tetraethylorthosilicate (TEOS) as a function of hydrolysis water ratio and organic content. 1H-13C CP/MAS NMR data indicate that the concentration of hydrolysis water (R value) has a fundamental effect on the nature of the acid-catalyzed hydrolysis and ring opening products. 1H-29Si CP/MAS NMR data suggest that for low R values, the ormosils are composed of a silica network with epoxide groups randomly dispersed throughout. At high R values, epoxide functionalities were found to coat the surfaces of dense silica particles. Salt spray analysis indicates that the corrosion resistance behavior of thin films derived from GLYMOTEOS ormosils decreases as the concentration of hydrolysis water increases and improves as the organic content in the film increases. These observations can be related to the underlying thin film structure.


2020 ◽  
Author(s):  
Mateus R. D. Carneiro ◽  
Bruno C. Freitas ◽  
Iuri B. de Barros ◽  
Jose Brant de Campos ◽  
Ivan N. Bastos ◽  
...  

Abstract The adhesion of coatings on a given substrate has fundamental importance on the functionality of a coating/substrate system. The current paper presents the adhesion strength results of FeCr and CoCr-based deposits produced by electric arc thermal spray process on carbon steel, with an intermediate layer of 95Ni5Al. Three chemical compositions were tested for coating deposition and was characterized using plate and tube specimens made of carbon steel UNS G10200 to result in a screening of performance. Microstructural evaluation by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed. Coating strength was measured using standard pull-off test method. The corrosion resistance was analyzed with salt spray exposure, electrochemical polarization and impedance spectroscopy (EIS) tests. The adhesion strength of FeCr and CoCr alloy coatings shows an overall average tensile strength of 27.2 MPa. All sealed conditions presented low corrosion and the samples with epoxy sealant exhibited a high resistance against corrosion. The X-ray diffraction results have revealed the presence of alpha and gamma FeCr alloys and chromite as deposited phases after the coating process.


2013 ◽  
Vol 537 ◽  
pp. 67-70
Author(s):  
Feng Zhang ◽  
Chuan Bing Huang ◽  
Wei Liu ◽  
Kui Zhou ◽  
Wen Ting Zhang ◽  
...  

Ni/BN and NiCrAl/BN abradable sealing coatings used in turbo engines were prepared by plasma spray technology. The phases and the microstructures of the coatings were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Corrosion behaviors of these coatings were investigated with open-circuit potential (OCP) and salt spray corrosion test. The results showed that the NiCrAl/BN possess better corrosion resistance as compared with Ni/BN.


2015 ◽  
Vol 44 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Akshya Kumar Guin ◽  
Manish Bhadu ◽  
Mohua Sinhababu ◽  
Tapan Kumar Rout ◽  
G. Udayabhanu

Purpose – This paper aims to investigate the potential of sol-gel coating as replacement for hazardous hexavalent chrome passivation treatment for galvanised iron (GI) sheet. Generally, corrosion resistance properties of the GI sheet are increased by hexavalent chrome passivation treatment. But hexavalent chrome is hazardous and not environment friendly. Design/methodology/approach – The aim of this study was to understand the effect of nano zinc oxide (ZnO) on corrosion behaviour of sol-gel coating prepared by hydrolysis of the 3-(Glycidoxy propyl) methyl diethoxy silane (GPTMS) and tetra-ethyl-orthosilicate (TEOS). The morphology of the film was characterised by a scanning electron microscope (SEM). The corrosion resistance of the coated samples was evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation curve and salt spray test. Findings – From a different corrosion resistance study, it has been observed that sol-gel coating doped with 1 per cent nano ZnO rendered maximum corrosion protection. Beyond 1 per cent of nano ZnO, corrosion resistance property of coated galvanised steel sheet decreased drastically which may be due to agglomeration of nano ZnO and high water permeability of coated galvanised steel sheet. Research limitations/implications – The anti-corrosive property of the coating can be tested by means of atmospheric exposure which produces a real-time evaluation of the anti-corrosive nature of the coating under natural conditions rather than using an accelerated laboratory test. Practical implications – It may be useful for other metal industry like aluminium. The work can be used as a guiding chemistry for development of chrome-free passivation for aluminium. Social implications – It has the potential to replace hexavalent chrome passivation. Originality/value – The use of nano ZnO in sol-gel polymer matrix for the development of corrosion resistant chrome-free polymer coating for galvanised steel sheet and its corrosion resistance study (EIS curve fitting, capacitance value and water permeability) is a novel approach in this research.


2011 ◽  
Vol 306-307 ◽  
pp. 3-6
Author(s):  
Hai Yang Zhao ◽  
Ya Kai Feng ◽  
Da Zhi Yang ◽  
Jin Tang Guo ◽  
Qing Liang Chen ◽  
...  

In order to improve the hemocompatibility of polycarbonateurethane (PCU), the biomimetic phosphorylcholine (PC) group was introduced onto material surface. Brush structure having PC groups was formed by ultraviolet (UV) initiated polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve the hydrophilicity and hemocompatibility of PCU surfaces. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electrical microscopy (SEM) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surfaces. Compared with original PCU, the PC-grafted PCU surfaces showed significantly high hydrophilicity as indicating by low water contact angle. The hemocompatibility of the PC-grafted PCU surfaces was evaluated by platelet adhesion test. The PCU surfaces modified with phosphorylcholine zwitterionic brushes showed effective resistance to platelet adhesion and high hemocompatibility. These PC-grafted PCU materials will have potential application as blood-contacting materials or devices due to their good mechanical and hemocompatible properties.


2007 ◽  
Vol 342-343 ◽  
pp. 809-812 ◽  
Author(s):  
Jian Xin Li ◽  
Jin Wang ◽  
Peng Li ◽  
Ya Jun Weng ◽  
Ling Ren ◽  
...  

of artificial blood catheters. This paper describes the immobilization of chitosan and heparin molecules on polyethylene terephthalate (PET) films by ozonization. The concentration of peroxide groups (-OOH) was 1.72 × 10-7 mol/cm2 on the PET surface oxidized by ozonization. The results of X-ray photoelectron spectroscopy (XPS) indicate that chains of chitosan and heparin were successfully immobilized on the PET films. The static contact angle(STA) of water decreases from 83.5° to 68.3° by immobilization of chitosan and heparin, which means that the hydrophilic properties of the modified PET is improved. The antithrombogenic property of PET surface was evaluated by a platelet-rich plasma (PRP) adhesion test. The results indicate that the number of platelet adhered on the modified-PET surface incubated with PRP for 240 min decreased significantly and platelets did not aggregate and distort.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 619
Author(s):  
Maciej Sowa ◽  
Marta Wala ◽  
Agata Blacha-Grzechnik ◽  
Artur Maciej ◽  
Alicja Kazek-Kęsik ◽  
...  

There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step method of oxide layer formation on 6061-T651 aluminum alloy (AAs) via alternating current (AC) plasma electrolytic oxidation (PEO), impregnation with an 8-hydroxyquinoline (8-HQ) solution, and final sealing by an additional direct current (DC) polarization in the original PEO electrolyte. The obtained coatings were characterized by scanning electron microscopy, roughness tests, contact angle measurements, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Additionally, corrosion resistance was assessed by potentiodynamic polarization in a NaCl solution. Two types of the coating were formed (A—thicker, more porous at 440 mA cm−2; B—thinner, more compact at 220 mA cm−2) on the AA substrate. The 8-HQ impregnation was successful as evidenced by XPS. It increased the contact angle only for the B coatings and improved the corrosion resistance of both coating systems. Additional DC treatment destroyed superficially adsorbed 8-HQ. However, it served to block the coating pores (contact angle ≈ 80°) which improved the corrosion resistance of the coating systems. DC sealing alone did not bring about the same anti-corrosion properties as the combined 8-HQ impregnation and DC treatment which dispels the notion that the provision of the inhibitor was a needless step in the procedure. The proposed method of AA surface treatment suffered from unsatisfactory uniformity of the sealing for the thicker coatings, which needs to be amended in future efforts for optimization of the procedure.


Sign in / Sign up

Export Citation Format

Share Document