Oxidation of Metals

2020 ◽  
Vol 29 (7/8) ◽  
pp. 30-33
Author(s):  
Seong-Gon KIM
Keyword(s):  
Oxide Layer ◽  
State Of The Art ◽  
Science And Technology ◽  
Electronic Devices ◽  
Modern Science ◽  
Conventional Theory ◽  
Negative Effects ◽  
Protective Oxide ◽  
Protective Oxide Layer ◽  
Positive Effects

Oxides are formed on the surfaces of most metals we use today when they are exposed to an environment suitable for oxidation. The formation of these oxides usually has negative effects that cause severe corrosion problems detrimental to the operation of electronic devices, but it can also have positive effects in that a protective oxide layer that prevents further penetration of oxygen into the material may be formed. Therefore, understanding the effect of oxidation in metals plays an important role in the advancement of modern science and technology. In this paper, we will review the conventional theory of oxidation and present a state-of-the-art model of oxidation based on recent discoveries.

Nanoporous anodic alumina obtained without protective oxide layer by hard anodization

2012 ◽  
Vol 67 (1) ◽  
pp. 296-299 ◽  
Author(s):  
A. Santos ◽  
P. Formentín ◽  
J. Ferré-Borrull ◽  
J. Pallarès ◽  
L.F. Marsal
Keyword(s):  
Oxide Layer ◽  
Anodic Alumina ◽  
Protective Oxide ◽  
Protective Oxide Layer ◽  
Nanoporous Anodic Alumina

scholarly journals Peningkatan Mutu Pembelajaran Agama Hindu Dalam Mewujudkan Perubahan Mental Siswa

2018 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Dewa A. R. Wulandari ◽  
I Nengah Juliawan
Keyword(s):  
Student Behavior ◽  
Science And Technology ◽  
Negative Effects ◽  
Positive Effects ◽  
Religious Learning ◽  
And Behavior ◽  
Attitudes And Behavior

<p><em>Advancement of science and technology is growing rapidly can lead to positive effects and negative effects on mental students, such as the still many students who are less disciplined in dressing at school or even when following the lesson in the classroom and the lower the morale owned of the students themselves. Seeing such a phenomenon is feared will be increasingly declining mental and student behavior. So in this case the improvement of the quality of Hindu religious learning is very important role for Hindus in particular and not limited to students, because religion is a guide in behaving well in accordance with religious norms that will bring good mental changes in improving attitudes and behavior behavior, personality and budhi pekerti and moral existing in learners.</em></p>

Selective exposure of platinum catalyst embedded in protective oxide layer on conductive titanium carbide support

2019 ◽  
Vol 13 ◽  
pp. 353-361
Author(s):  
Zishuai Zhang ◽  
Mohammad Amin Sadeghi ◽  
Nicolas Brodusch ◽  
Raynald Gauvin ◽  
Siyu Ye ◽  
...  
Keyword(s):  
Titanium Carbide ◽  
Oxide Layer ◽  
Platinum Catalyst ◽  
Selective Exposure ◽  
Protective Oxide ◽  
Protective Oxide Layer

The effects of peripheral service quality on spectators’ emotions and behavioural intentions

2019 ◽  
Vol 20 (3) ◽  
pp. 495-515 ◽  
Author(s):  
Behzad Foroughi ◽  
Khairul Anuar Mohammad Shah ◽  
Thurasamy Ramayah ◽  
Mohammad Iranmanesh
Keyword(s):  
Service Quality ◽  
Electronic Devices ◽  
Negative Effects ◽  
Content Type ◽  
Behavioural Intentions ◽  
Positive Effects ◽  
Football Match ◽  
Football Stadiums ◽  
Unpleasant Emotion

Purpose The purpose of this paper is to investigate the impacts of peripheral service quality on football match spectators’ emotions and behavioural intention. Design/methodology/approach Data were obtained from a survey of 342 spectators of professional league football in Malaysia and analysed using the partial least squares technique. Findings The results illustrated the significant role of both pleasant and unpleasant emotions in forming spectators’ behavioural intentions. Furthermore, they demonstrated that the drivers of pleasant and unpleasant emotions are different. While entertainment, electronic devices and stadium announcers have positive effects on pleasant emotion, facilities and electronic devices have negative effects on unpleasant emotion. Entertainment, electronic devices and stadium announcers have indirect effects on behavioural intentions through pleasant emotions. Unpleasant emotions mediated the effects of facilities and electronic devices on behavioural intentions. Originality/value The findings of this study suggest that football marketers must understand the crucial role of peripheral service quality and spectators’ emotions. Through stimulating pleasant emotions in spectators and preventing unpleasant emotions from arising, football marketers can ensure that these spectators will attend football stadiums.

Free fatty acid influenced corrosion inhibition mechanisms of some inedible plants seeds oils on low alloyed medium-carbon steel in H2SO4

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Olanrewaju Moses Adesusi ◽  
Olayide Rasaq Adetunji ◽  
Tunji John Erinle ◽  
Iliyasu Kayode Okediran ◽  
Olumide Olufunso Akinpelu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Carbon Steel ◽  
Free Fatty Acid ◽  
Oxide Layer ◽  
Corrosion Inhibition ◽  
Medium Carbon Steel ◽  
Protective Oxide ◽  
Medium Carbon ◽  
Protective Oxide Layer ◽  
Content Type

Purpose The purpose of this paper is to investigate the mechanisms of low alloyed medium-carbon steel (LAMCS) corrosion in 0.5 M H2SO4 inhibited by seeds oils of rubber (SOR), Neem (SON) and Jatropha (SOJ) containing varying degree of free fatty acid (FFA). Design/methodology/approach Specific gravity, acid values and FFA compositions of oils were determined. Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) are techniques used to investigate the corrosion inhibition mechanisms with evaluated Gibbs free energy of adsorption. Findings Corrosion inhibition efficiencies of oils reached values >99% as obtained from PDP and EIS. Protective oxide layer was formed on LAMCS consequent on containment of carbonyl and hydroxyl groups in the FFA of SOR, SON and SOJ, respectively. The SOR and SOJ are found to be mixed inhibitors, whereas SON behaved as anodic inhibitor. Mechanism of adsorption of SOR was synergistic between physisorption and chemisorption, while SON and SOJ exhibited physisorption. SEM micrographs images showed that uninhibited sample exhibited thicker mass of corrosion products. Formation of protective oxide layer was confirmed by XRD diffractograms. Practical implications This study has shown that the need for modification of vegetable seed oils containing FFA is unnecessary as the hydroxyl and carbonyl groups of the FFA contained in the respective oil were found to be the center of adsorption of the oils on the steel surface. Hence, cost and by-products associated with modification of oils used as corrosion inhibitors are eliminated. Originality/value SOR, which has the highest percentage FFA, was found to be the most influential on the corrosion inhibition mechanism of LAMCS, specifically within 0.01–0.02 g/mL concentration. FFA contained in the respective seed oil aided formation of protective oxide layer at interface between H2SO4 and LAMCS, relative to amount composed.

The formation of a protective oxide layer in machining resulphurized free-cutting steels and cast irons

Wear ◽  
1990 ◽  
Vol 139 (2) ◽  
pp. 195-208 ◽  
Author(s):  
Y. Yamane ◽  
H. Usuki ◽  
B. Yan ◽  
N. Narutaki
Keyword(s):  
Oxide Layer ◽  
Cast Irons ◽  
Protective Oxide ◽  
Protective Oxide Layer

Stability of Protective Oxide Layer Against Corrosion: Solubility Measurements of Chromium in Soda Lime Silicate Melts

2013 ◽  
Vol 80 (5-6) ◽  
pp. 611-622 ◽  
Author(s):  
Tuti Katrina Abdullah ◽  
Carine Petitjean ◽  
Pierre-Jean Panteix ◽  
Christophe Rapin ◽  
Michel Vilasi ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Soda Lime ◽  
Silicate Melts ◽  
Protective Oxide ◽  
Protective Oxide Layer

scholarly journals Comprehensive investigation of the corrosion state and surface properties of the stainless steel tubes of steam generators

2021 ◽  
Vol 9 (3) ◽  
Author(s):  
Andrea Szabó Nagy ◽  
Kálmán Varga ◽  
Bernadett Baja ◽  
Zoltán Németh ◽  
Deszo Oravetz ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heat Exchanger ◽  
Chemical Composition ◽  
Oxide Layer ◽  
General Corrosion ◽  
Steam Generators ◽  
Protective Oxide ◽  
Comprehensive Investigation ◽  
Protective Oxide Layer ◽  
Corrosion State

Evaluating the water chemistry in the primary circuit and the effect of chemical econtamination of the heat exchanger tubes performed by the AP-CITROX (AP: alkaline permanganate; CITROX: citric and oxalic acid) procedure at Paks NPP (Hungary), a project dealing with the comprehensive investigation of the general corrosion state of the steam generators (SGs) has been initiated. Owing to the fact that there is no investigation method available for the in-situ monitoring of the inner surfaces of heat exchanger tubes, a research program based on sampling as well as on ex-situ electrochemical (voltammetric) and surface analytical measurements (SEM-EDX, CEMS, XRD, XPS) was developed and elaborated. In the time period of 2000-2008 - within the frame of the above project - 45 stainless steel specimens, cut out from various locations of the steam generators of the Paks NPP were investigated. Based on the measured corrosion characteristics (corrosion rate, thickness and chemical composition of the protective oxide-layer) it was found that these parameters are strongly dependent on the decontamination history of steam generators. The present work gives a brief overview on the general corrosion state of the heat exchanger tubes of SGs, concerning the long-term effects of the AP-CITROX procedure on the chemical composition and structure of the protective oxide-layer.

scholarly journals Effect of Drum Pressure on Flow Accelerated Corrosion in Gas Fired Combined Cycle Power Plant: A Case Study and Literature Review

2019 ◽  
Vol 2 ◽  
pp. 17-27
Author(s):  
Ujjal Kumar ◽  
Chamely Khatun ◽  
Md Sakinul Islam ◽  
Nhol Kao ◽  
Fazle Rabbi ◽  
...  
Keyword(s):  
Power Plant ◽  
Oxide Layer ◽  
Control Valve ◽  
Combined Cycle ◽  
Protective Oxide ◽  
Accelerated Corrosion ◽  
Protective Oxide Layer ◽  
Flow Accelerated Corrosion ◽  
Water Turbulence

The dissolution of ferrous ions from the protective oxide layer and/or base metal by corrosion with the assistance of turbulent flow is called flow accelerated corrosion (FAC). Flow accelerated corrosion is the most common and continuous corrosion reaction in combined cycle power plants (CCPP). Heat recovery steam generator (HRSG) drum pressure fluctuation and/or turbulent drum water greatly influences the FAC of drum and economizer. This kind of FAC was investigated in the low-pressure drum (LPD) and low-pressure economizer (LPE) of a 210 MW gas-fired combined cycle power plant (Four-unit HRSG & GT) with an air-cooled condenser (ACC). Severe FAC was observed due to the fluctuation of pressure in the LPD with respect to time. As a result, huge amounts of soluble iron (Fe2+) and insoluble (Fe3+) was found in all running HRSG’s LPD water. Due to pressure fluctuations in the LPD, a protective oxide layer (mostly magnetite), as well as the base metal, were corroded from the LPD and LPE even after carefully maintaining recently developed water cycle chemistry in this CCPP. Severe leakage was found in the LPE due to corrosion. The actual reason for the problem was found to be a malfunctioning steam-control valve in the turbine unit’s LP system. This valve was malfunctioning by suddenly opening to 100% and then closing to around 10% continuously. This malfunction creates enormous pressure drops in both the LPD and LPE units. It is understood that water turbulence is the main cause of FAC affecting the LDP and LPE. This assessment is based on chemical laboratory analysis and physical inspection. There was no non-destructive testing (NDT) performed in this study. The severe FAC happened in four days and for this reason, HRSG and steam turbines were shut down. Maintenance work on the control valve and flushing of the LPD and LPE successfully resolved the FAC problem. One week later, LPE leakage was found on the unit-3 HRSG and as reported in this study this was also found to be the result of FAC. From this case study, it is concluded that not only water quality but also water turbulence can create severe FAC problem.

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