scholarly journals Study on Corrosion of Macroporous Silicon in Sodium Hydroxide Solution by Electrochemical Methods and Scanning Electron Microscopy

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Chuan Lai ◽  
Zhen Xiang ◽  
Changlu Liu ◽  
Chaoju Zhu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Linear Polarization ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Open Circuit ◽  
Macroporous Silicon ◽  
Linear Polarization Resistance ◽  
Scanning Electron

The fabricated macroporous silicon with a porosity of 26.33% corrosion in NaOH solution was systemically investigated by open circuit potential measurements, linear polarization measurements, potentiodynamic polarization measurements, and scanning electron microscopy, respectively. Results show that the potential open circuit and linear polarization resistance decreases with the NaOH concentration increasing. The corrosion potential shifts significantly to more negative potentials and corrosion current density increases with NaOH concentration increasing. Adding ethanol to 1.0 M NaOH can lead to the linear polarization resistance decrease, corrosion potentials shift in the positive direction, and corrosion current density increase. In addition, the scanning electron microscopy images demonstrate that the macroporous silicon samples are seriously damaged by 1.0 M NaOH and 1.0 M NaOH/EtOH (30%).

Effect of Bi Addition on the Electrochemical Behavior of Zinc Electrodes in Concentrated Alkaline Solutions

2013 ◽  
Vol 805-806 ◽  
pp. 1240-1249
Author(s):  
Hong Xia Liang ◽  
Fu Rong Li ◽  
Zhi Lin Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Linear Polarization ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Exchange Current ◽  
Zinc Electrode ◽  
Current Densities ◽  
Scanning Electron

The electrochemical behavior of zinc electrode with bismuth addition in 35%KOH solutions has been investigated systematically by electrochemical methods including linear polarization, potentiostatic polarization, potential-time measurements at a constant current density, combining the observations of scanning electron microscopy (SEM). Linear polarization results showed that the open circuit potential shifted positively with increasing bismuth content, which is explained based on the gassing data and change in the exchange current of the zinc electrode. Addition of bismuth increased the exchange current of zinc reaction and caused an increase in the measured open circuit potential. Galvanostatic results showed that the addition of bismuth shortened the passivation time. Scanning electron microscopy images showed that the addition of bismuth aggravated the corrosion of zinc electrode which may be responsible for the increased tendency to passivation at high current densities. It has been found that at low current densities the reaction kinetics may be increased by addition of Bi, which is general agreement with the discharging test of actual alkaline batteries.

scholarly journals Corrosion behaviour of an AlZnSnSrGa alloy in aqueous solutions of NaCl and Na2So4

2000 ◽  
Vol 65 (1) ◽  
pp. 73-81
Author(s):  
P. Zivkovic ◽  
J. Pjescic ◽  
S. Mentus
Keyword(s):  
Corrosion Rate ◽  
Aqueous Solutions ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Behaviour ◽  
Base Material ◽  
Corrosion Current ◽  
Open Circuit ◽  
Base Metals ◽  
Aluminium Plant

The alloy composed of Al(95.53%), Zn(2.85%), Sn(0.515%), Ga(0.1%) and Sr(0.009%), with the weight percents in the parentheses, was prepared by melting, using Al(99.84%), a product of the Aluminium Plant-Podgorica, as the base material. The corrosion behaviour of this alloy was tested in relation to the behaviour of the base metals, by both open curcuit potential and polarization resistance methods, in aqueous solutions of both NaCl and Na2SO4, the concentration of which varied within the range 0.00051 - 0.51 mol dm -3. Over the whole salt concentration ranges, the corrosion parameters indicate that the corrosion rate of the alloy is significantly higher than the rate of the base material. For instance, for the concentration range 0.00051 - 0.51 mol dm -3 , the stationary open circuit potentials, related to SCE, in NaCl solutions were - 1.200 to - 1.460 V for the alloy and - 0.693 to - 0.920 V for Al, while in Na2SO4 solutions, the stationary open circuit potentials were - 1.190 to - 1.465V for the alloy and - 0.780 to - 0.860V for Al. At the same time, the corrosion current density in NaCl solutions varied within 11-89 mA cm -2 for the alloy and 0.35 - 0.80 for Al, while in Na2SO4 solutions it amounted to 5.7.52 mA cm -2 for the alloy and 0.28 - 0.88 mA cm -2 for Al.

Corrosion Inhibition of Zinc in KOH Solutions

2007 ◽  
Vol 23 ◽  
pp. 233-236 ◽  
Author(s):  
Alina Prună ◽  
V. Brânzoi ◽  
F. Brânzoi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polarization Resistance ◽  
Cathodic Polarization ◽  
Effective Surface ◽  
Zinc Surface ◽  
Alkylammonium Salts ◽  
Morphology Characteristics ◽  
Potentiodynamic Method ◽  
Scanning Electron

The influence of electrolyte additions on the corrosion of zinc in aqueous solutions of KOH has been determined using electrochemical and nonelectrochemical techniques. These included anodic and cathodic polarization resistance and potentiodynamic method. The inhibitors studied included ZnO and tetra-alkylammonium bromides in different concentrations. From the data provided corrosion currents were calculated. The effectiveness of the inhibitors was compared and it was found that combinations of zinc oxide with tetra-alkylammonium salts were the most effective. Surface analysis obtained with scanning electron microscopy (SEM) revealed morphology characteristics developed at the zinc surface.

scholarly journals Galvanic Corrosion between Depleted Uranium and 40Cr Steel

2012 ◽  
Vol 531-532 ◽  
pp. 220-225
Author(s):  
Zhen Pu ◽  
Qing Fu Wang ◽  
Mao Bin Shuai ◽  
Ding Mu Lang
Keyword(s):  
Current Density ◽  
Linear Polarization ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Depleted Uranium ◽  
Accelerated Corrosion ◽  
Linear Polarization Resistance ◽  
Corrosion Behaviors ◽  
40Cr Steel

Individual corrosion and galvanic corrosion behaviors of depleted uranium (DU) and 40Cr steel were investigated by electrochemical analyzing technologies in 3.5w.t%NaCl solution, including open circuit potential(OCP) test, linear polarization(LP) test, potentiodynamic polarizaition(PD) test, galvanic corrosion potential and corrosion current density test. The results reveal that the OCP of DU and 40Cr steel are around -790mV and -660mV, respectively. 40Cr has a higher linear polarization resistance than DU in galvanic corrosion. The dynamic processes of galvanic corrosion goes through an conversion in the whole test period. DU acts as anode with an accelerated corrosion rate, while the 40Cr steel behaves as cathode during the process of galvanic corrosion for DU/40Cr couple. The galvanic potential and current density of the DU/40Cr couple are -780mV and 17.5μA/cm-2, respectively.

scholarly journals Anti-tarnish silver alloys in system Ag-Cu-Zn-Si with the addition of aluminum

10.30544/386 ◽  
2018 ◽  
Vol 24 (3) ◽  
pp. 181-188
Author(s):  
Marija Korać ◽  
Stevan Dimitrijević ◽  
Kemal Delijić ◽  
Željko Kamberović
Keyword(s):  
Linear Polarization ◽  
Polarization Resistance ◽  
Open Circuit Potential ◽  
Sodium Sulfide ◽  
Open Circuit ◽  
Silver Alloys ◽  
Linear Polarization Resistance ◽  
Sodium Sulfide Solution ◽  
Sulfide Solution ◽  
Polarization Resistance Method

This paper presents investigations of aluminum addition influence on the corrosion characteristics of the sterling silver Ag-Cu-Zn-Si alloys. The procedure for obtaining Ag-Cu-Zn-Al-Si alloys in small ranges of predefined composition was also presented. Open circuit potential measurements, linear polarization resistance method and potentiodynamic polarization tests were employed to determine corrosion characteristics of the alloys. The materials were tested in a 0.01M sodium sulfide solution. It was shown that the addition of aluminum improves sulfidization resistance and corrosion characteristics. Best results are achieved for the alloy with the following composition 92.5% Ag, 1.9% Cu, 3.7% Zn, 1.6% Al and 0.3% Si.

scholarly journals Understanding the Nature of the Manganese Hot Dip Phosphatizing Process of Steel

2017 ◽  
Vol 57 (4) ◽  
Author(s):  
Gabriela Alvarado-Macías ◽  
Juan Carlos Fuentes-Aceituno ◽  
Armando Salinas-Rodríguez ◽  
Francisco Javier Rodríguez-Varela
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phosphoric Acid ◽  
Species Distribution ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
The Other ◽  
Energy Dispersive ◽  
X Ray ◽  
Scanning Electron

In this work, the phosphatizing process of steel is investigated using open circuit potential and Tafel curves as well as scanning electron microscopy and energy dispersive X-ray spectroscopy. The results reveal that a pH of 2.57 in the phosphatizing solution promotes the dissociation of phosphoric acid which assists the formation of the manganese tertiary salt (Mn<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>), which is deposited on the substrate. It was also observed that an increase in the temperature from 25 to 90°C and the presence of HNO<sub>3</sub> as catalyst enhances the manganese phosphatizing kinetics. On the other hand, the generation of iron phosphates and oxides is predominant at a pH of 1 and 90°C. These observations are supported by species distribution and Pourbaix thermodynamic diagrams.

Fabrication and Photoresponse of Self-Organized TiO2 Mesoporous by Alternative Voltage Condition

2012 ◽  
Vol 626 ◽  
pp. 580-583
Author(s):  
Pacharee Krongkitsiri ◽  
Udom Tipparach
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxalic Acid ◽  
Open Circuit Potential ◽  
Pure Titanium ◽  
Open Circuit ◽  
Self Organized ◽  
Anodization Method ◽  
Scanning Electron

Mesoporous of TiO2electrodes (MOTE) were fabricated on pure titanium sheets in aqueous based electrolytes that consist of NaSO4NH4F and Oxalic acid by an anodization method with alternative voltage condition. Morphology of MOTE was characterized by scanning electron microscopy. The characteristic photoresponse in 0.1 M Na2SO4on the MOTE was investigated. The MOTE shows an excellent photoresponse property that is significant at low open-circuit potential.

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