Corrosion Behaviour of Nanocrystalline Zn-Ni and Zn-Ni-Co Electrodeposits

2011 ◽  
Vol 409 ◽  
pp. 526-531 ◽  
Author(s):  
L. Monaco ◽  
J.L. McCrea ◽  
G. Palumbo ◽  
Uwe Erb
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Surface Morphology ◽  
Corrosion Behaviour ◽  
High Strength ◽  
Corrosion Resistant ◽  
X Ray ◽  
Scanning Electron

In this study, alternatives to corrosion-resistant cadmium coatings on high strength steel fasteners are explored. Nanocrystalline Zn-Ni and Zn-Ni-Co electrodeposits, synthesized by electrochemical deposition, were analyzed by potentiodynamic polarization in a 1M NaCl aqueous solution, to determine the corrosion behaviour of the alloys. Sample coatings were characterized using scanning electron microscopy to examine differences in surface morphology that can affect corrosion resistance. Energy dispersive x-ray spectroscopy was used to relate composition to corrosion resistance and to characterize the corrosion behavior during polarization. All coatings showed corrosion potentials at equivalent, or lower values than that of cadmium, suggesting that both alloys are viable as cadmium replacements. Specific compositions showed slightly passivating regions, but the brittle film formed during polarization is unstable. Comparatively, Zn-Ni shows a better resistance to corrosion than Zn-Ni-Co. The effect of composition on the corrosion resistance can be explained on the basis of the sacrificial depletion of Zn over Ni.

Corrosion Behaviour of AZ91DSm1.0 with Different Preparation Methods

2014 ◽  
Vol 1004-1005 ◽  
pp. 113-118
Author(s):  
Hong Xia Liu ◽  
Jin Liang ◽  
Jue Zhang ◽  
Xiao Lian Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
X Ray Diffraction ◽  
Vacuum Melting ◽  
Potentiodynamic Polarization Curve ◽  
Preparation Methods ◽  
X Ray ◽  
Scanning Electron

Corrosion behaviour of AZ91DSm1.0 with different preparation methods(vacuum melting and common melting) is investigated. X-ray diffraction(XRD), optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), corrosion weightless experiment and the potentiodynamic polarization curve are applied to characterize the corrosion behaviour. Results show that vacuum melting alloy possess higher corrosion resistance than common melting alloy. This is attributed to the rod-shaped Al3Sm which was formed in common melting alloy will have certain fragmentation effect on matrix that can lead to defects.

Influence of Fly Ash on Corrosion Resistance of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Fly Ash ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Zones ◽  
Refractory Ceramics ◽  
Scanning Electron

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.

scholarly journals Preparation, Characterization, and Photocatalytic Properties of Modified Red Mud

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Mingjie Ma ◽  
Guanyu Wang ◽  
Zhengpeng Yang ◽  
Shanxiu Huang ◽  
Weijie Guo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Uv Irradiation ◽  
Red Mud ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrf Scanning ◽  
Scanning Electron

Solid waste red mud was modified by HCl leaching. The structure property and composition of modified red mud were investigated by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Under UV irradiation, methyl orange (MO) aqueous solution was photodegraded by modified red mud. The obtained results showed that the specific surface area of modified red mud was 317.14 m2/g, which was about 40 times higher than that of the normal red mud. After UV irradiation for 50 min, the removal percentage of MO reached 94.2%. The study provided a novel way for the application of red mud to the photocatalytic degradation of organic wastes.

The Effect of Accelerator Types on the Phosphated Zn-%12Ni Electrodeposite Coating

2018 ◽  
Author(s):  
Hafez Alizadeh ◽  
Amir Hanaei ◽  
Behzad Heidarshenas ◽  
Armita Shahbazkhan ◽  
Naghi Parvini Ahmadi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Phosphate Solution ◽  
Surface Porosity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrate And Nitrite ◽  
Coating Weight ◽  
Scanning Electron

The aim of this study is to investigate the effect of nitrate and nitrite on the weight, morphology and electrochemical properties of phosphated Zn-%12Ni electrodeposite coatings. In order to investigate the phase structure and surface morphology of samples, X-ray diffraction and scanning electron microscopy were employed. Also, to measure the corrosion resistance behavior of the coats, Potentiostat/Galvanostat test was used. The results showed that nitrite accelerator reduces coating weight and surface porosity simultaneously obtaining by phosphate solution. Furthermore, coatings being obtained by the nitrite accelerator had a higher corrosion resistance than that of the nitrate accelerator.

Corrosion of titanium diboride in molten FLiNaK(eut)

2012 ◽  
Vol 66 (11) ◽  
Author(s):  
Viliam Pavlík ◽  
Miroslav Boča
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Hot Isostatic Pressing ◽  
X Ray ◽  
Eutectic Salt ◽  
Mass Losses ◽  
Grain Formation ◽  
Nickel Addition ◽  
Scanning Electron

AbstractPure and enriched titanium dibromide (TiB2) samples (prepared by hot isostatic pressing) with different mole ratios of Ni and Ta were investigated in contact with molten eutectic salt (FLiNaK(eut); LiF/NaF/KF 42.5 mole %: 11.5 mole %: 42.0 mole %) at 600°C. Corrosion resistance of the materials was studied, the mass losses and depths of corrosion were calculated, and sample surfaces were investigated by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). Nickel addition decreased the corrosion resistance of TiB2. Simultaneous additions of both elements, Ni and Ta, as well as the addition of Ta only showed reducing effect on grain formation and they increased the corrosion resistance which is highest in the last case.

Research on Preparation and Properties of Al-Mn Alloy Coating in NaCl-KCl-AlCl3-NdCl3 Molten Salts

2011 ◽  
Vol 121-126 ◽  
pp. 335-339
Author(s):  
Xian Jin Yu ◽  
Li Peng Zhang ◽  
Zhi Wei Ge ◽  
Yun Hui Dong ◽  
Dang Gang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Molten Salts ◽  
Alloy Coating ◽  
Surface Coatings ◽  
X Ray Diffraction ◽  
Pitting Potential ◽  
X Ray ◽  
Scanning Electron

Al-Mn alloy coatings were electrodeposited on an iron substrate from AlCl3-NaCl-KCl low-temperature molten salts with anhydrous MnCl2 enhanced by the addition of NdCl3.The microstructure and properties of the Al-Mn alloy coatings were investigated, and scanning electron microscopy, X-ray diffraction, and polarization curves were used to determine the composition, surface morphology, phase structure, and corrosion resistance of the obtained deposits. The results show that the surface coatings were smooth, and that the crystallites were dense and uniform when 0.23 wt% NdCl3 was added to the molten salt. An amorphous mixture of Al and Al6Mn was obtained. NdCl3 enhanced the corrosion resistance and increased the hardness of the single amorphous phase alloys. The pitting potential of the coating was approximately −1.04V, and its hardness was 392 kgf/mm2.

scholarly journals Corrosion Behaviour of Zn-10Al-1.5Cu Alloy

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
C. N. Panagopoulos ◽  
A. G. Tsopani
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Solution Concentration ◽  
Solution Temperature ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nacl Concentration ◽  
Scanning Electron

The corrosion behaviour of Zn-10Al-1.5Cu alloy in NaCl solution was examined. The used NaCl solution concentrations were 1M, 0.3M, and 0.003M for a constant temperature values of 7°C or 25°C or 45°C. The corrosion behaviour of this alloy was investigated under potentiodynamic corrosion conditions. The surface of the corroded alloy specimens was studied with the aid of scanning electron microscopy and X-ray diffraction techniques. It was observed that the increase of NaCl concentration in the corrosion solution for a constant value of temperature led to lower corrosion resistance of the alloy. For a constant value of solution concentration, the increase of solution temperature also led to the decrease of corrosion resistance of the same alloy.

Effects of graphene on the microstructure and properties of MAO coatings formed on AA7050

2020 ◽  
Vol 111 (6) ◽  
pp. 463-468
Author(s):  
Bo Xu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
Weimin Gan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Composite Coatings ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Scanning Electron

Abstract Ceramic coatings were prepared on the surface of 7050 highstrength aluminum alloy using micro-arc oxidation in an aluminate electrolyte with added graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and electrochemical measurements were used, respectively. The addition of 9 g · L-1 of graphene to the electrolyte decreased the micro-pore size of the composite coatings and improved the density. In addition, with the addition of graphene, the roughness was the lowest, and the corrosion resistance was significantly improved.

Effect of Ti and Sb Elements Addition on the Microstructure and Corrosion Resistance of Hot-Dip Galvanized Zn-11Al-3Mg Alloy

2021 ◽  
Vol 1035 ◽  
pp. 630-637
Author(s):  
Hui Jie Sun ◽  
Guo Rong Zhou ◽  
Ming Ming Zhang ◽  
Xue Feng Wang ◽  
Shui Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Energy Dispersive Spectrometry ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Pitting Corrosion Resistance ◽  
Scanning Electron

The effect of Ti and Sb elements addition on the microstructures and corrosion resistance of hot-dip galvanized Zn-11Al-3Mg alloy was investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and Electrochemical workstation, respectively. Results showed that the grain size of the alloy was obviously refined with the addition of Ti and Sb elements, due to Al3Ti phase as the nucleation substrate resulted in the transformation of Al-rich phase from dendrite to petal-like. In addition, the pitting corrosion resistance of the alloy has been significantly enhanced.

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