scholarly journals Galvanic corrosion inhibition from aspect of bonding orbital theory in Cu/Ru barrier CMP

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kangchun Lee ◽  
Seho Sun ◽  
Ganggyu Lee ◽  
Gyeonghui Yoon ◽  
Donghyeok Kim ◽  
...  
Keyword(s):  
Corrosion Inhibition ◽  
Adsorption Layer ◽  
Interaction Analysis ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Chemical Mechanical Planarization ◽  
Electron Configuration ◽  
Orbital Theory ◽  
Native Oxides ◽  
The Difference

AbstractIn this report, the galvanic corrosion inhibition between Cu and Ru metal films is studied, based on bonding orbital theory, using pyridinecarboxylic acid groups which show different affinities depending on the electron configuration of each metal resulting from a π-backbonding. The sp2 carbon atoms adjacent to nitrogen in the pyridine ring provide π-acceptor which forms a complex with filled d-orbital of native oxides on Cu and Ru metal film. The difference in the d-orbital electron density of each metal oxide leads to different π-backbonding strength, resulting in dense or sparse adsorption on native metal oxides. The dense adsorption layer is formed on native Cu oxide film due to the full-filled d-orbital electrons, which effectively suppresses anodic reaction in Cu film. On the other hand, only a sparse adsorption layer is formed on native Ru oxide due to its relatively weak affinity between partially filled d-orbital and pyridine groups. The adsorption behaviour is investigated through interfacial interaction analysis and electrochemical interaction evaluation. Based on this finding, the galvanic corrosion behaviour between Cu and Ru during chemical mechanical planarization (CMP) processing has been controlled.

scholarly journals Causal Interaction and Effect Modification: Same Model, Different Concepts

2017 ◽  
Author(s):  
Luke Keele ◽  
Randolph T. Stevenson
Keyword(s):  
Political Science ◽  
Regression Models ◽  
Interaction Analysis ◽  
Effect Modification ◽  
The Political ◽  
Science Literature ◽  
Causal Interaction ◽  
Single Treatment ◽  
Social Scientists ◽  
The Difference

Social scientists use the concept of interactions to study effect dependency. Such analyses can be conducted using standard regression models. However, an interaction analysis may represent either a causal interaction or effect modification. Under causal interaction, the analyst is interested in whether two treatments have differing effects when both are administered. Under effect modification, the analysts investigates whether the effect of a single treatment varies across levels of a baseline covariate. Importantly, the identification assumptions for these two types of analysis are very different. In this paper, we clarify the difference between these two types of interaction analysis. We demonstrate that this distinction is mostly ignored in the political science literature. We conclude with a review of several applications.

scholarly journals Galvanic Corrosion Behaviour of Phosphate Nodular Cast Iron in Different Types of Residual Waters and Couplings

2019 ◽  
Vol 70 (10) ◽  
pp. 3597-3602 ◽  
Author(s):  
Carmen Nejneru ◽  
Manuela Cristina Perju ◽  
Dumitru Doru Burduhos Nergis ◽  
Andrei Victor Sandu ◽  
Costica Bejinariu
Keyword(s):  
Cast Iron ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Nodular Cast Iron ◽  
Low Alloy Steel ◽  
High Chemical ◽  
Different Types ◽  
Grey Cast ◽  
Main Components ◽  
Galvanic Corrosion Behaviour

The aim of this paper is to analyze the corrosion process that occurs in galvanic couplings of different alloys. The study focuses on materials that can come into contact in submersible pumps used by water treatment plants. Because, the rotor, one of the pump main components must possess high chemical and mechanical properties, nodular cast iron is usually used. Therefore, this is exposed in the same environment with different types of materials, such as aluminum, copper, bronze, grey cast iron, low alloy steel or stainless steel from which other components are made. The tests have been performed in three types of residual waters with neutral, acidic and basic pH. According to this study, the nodular cast iron galvanic corrosion resistance is highly improved by the phosphate layer deposited on its surface.

scholarly journals Corrosion resistance of metalized layers on steel parts in ventilation mill

10.30544/340 ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 123-132
Author(s):  
Bore V. Jegdic ◽  
Bojana M. Radojković ◽  
Biljana M. Bobić ◽  
Marija M. Krmar ◽  
Slavica Ristić
Keyword(s):  
Corrosion Rate ◽  
Base Metal ◽  
Galvanic Corrosion ◽  
Thermal Power ◽  
Electrochemical Techniques ◽  
General Corrosion ◽  
Hvof Process ◽  
The Difference ◽  
Local Dissolution ◽  
Oxygen Fuel

Corrosion behavior of metalized layers, obtained by Plasma Transferred Arc (PTA) process and by High-Velocity Oxygen Fuel (HVOF) process with the purpose to improve the wear resistance of vital parts of ventilation mill in a thermal power plant, has been tested. The test is performed using three electrochemical techniques, in a solution containing chloride and sulfate ions. It is shown that the steel surface (base metal) dissolves uniformly, without pitting or other forms of local dissolution. Morphology of metalized layers surface indicates that dissolution is non-uniform, but it still can be considered as general corrosion. The corrosion rate of base metal and metalized layer obtained by PTA process is rather low, while the corrosion rate of the metalized layer obtained by HVOF process is much higher. Also, the difference in corrosion potentials between the base metal and the HVOF layer is pretty high but slightly less than maximum allowed difference (prescribed by the standard), to avoid excessive galvanic corrosion. The values of corrosion rate obtained by different electrochemical techniques are in excellent agreement.

scholarly journals Corrosion Inhibition of Mild Steel in Acidic Media by N-[(3,4-Dimethoxyphenyl)Methyleneamino]-4-Hydroxy-Benzamide

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kashmitha Muthamma ◽  
Preethi Kumari ◽  
M. Lavanya ◽  
Suma A. Rao
Keyword(s):  
Dft Calculations ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Surface Characterization ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Low Carbon ◽  
Acid Media

Abstract Mild steel (a low carbon steel) is an affordable engineering material used for many purposes in various environments including mild acidic environment with some precautions. The corrosion behaviour of mild steel (MS) in 0.5 M H2SO4 and 0.5 M HCl, in the temperature range (303–323 K) without and with the inhibitor N-[(3,4-dimethoxyphenyl) methyleneamino]-4-hydroxy-benzamide (DMHB), was investigated using Potentiodynamic polarization and Electrochemical impedance spectroscopy (EIS) techniques supplementing with surface characterization study using scanning electron microscope (SEM) and atomic force spectroscopy (AFM). Experimental observations were found to be in agreement with Density functional theory (DFT) calculations. The inhibition efficiency increases with increase in DMHB concentration and showed maximum inhibition efficiency of 86% in 0.5 M H2SO4 and 81% in 0.5 M HCl, respectively, at concentration of 3 × 10─3 M at 303 K. The inhibition efficiency of DMHB obtained relatively at its lower concentration (3 × 10─3 M) compared to other reported related compounds confirms its potential towards corrosion inhibition. The variation in the kinetic and thermodynamic parameters indicated physisorption of DMHB on MS and its mixed type inhibitive action followed Langmuir’s isotherm model. DFT calculations go along with the experimental results, signifying the potential corrosion inhibition behaviour of DMHB for MS in both the acid media.

The mechanisms of corrosion inhibition of hot-dip galvanized steel by vanadyl oxalate: A galvanic corrosion investigation supported by XPS

2018 ◽  
Vol 142 ◽  
pp. 153-160 ◽  
Author(s):  
Zhiqiang Gao ◽  
Dawei Zhang ◽  
Xiaopan Qiu ◽  
Sheming Jiang ◽  
Yucheng Wu ◽  
...  
Keyword(s):  
Corrosion Inhibition ◽  
Galvanic Corrosion ◽  
Galvanized Steel ◽  
Corrosion Investigation

5d and 4f electron configuration of CeB6 at 340 and 535 K

2008 ◽  
Vol 64 (5) ◽  
pp. 534-549 ◽  
Author(s):  
Ryoko Makita ◽  
Kiyoaki Tanaka ◽  
Yoshichika Ōnuki
Keyword(s):  
Electron Transfer ◽  
Crystal Field ◽  
Ground State ◽  
Room Temperature ◽  
Atomic Orbital ◽  
Energy Levels ◽  
Electron Configuration ◽  
Acta Cryst ◽  
X Ray ◽  
The Difference

X-ray atomic orbital (XAO) analysis revealed that at both temperatures the electrons are transferred from B 2px (= py ) to Ce 5d and 4f orbitals. At 340 K 5d(j = 5/2)Γ8 orbitals are occupied partially, but 4f(j = 5/2)Γ8 orbitals are more populated than 4f(j = 5/2)Γ7 orbitals, in contrast to our observation at 430 K [Makita et al. (2007). Acta Cryst. B63, 683–692]. At 535 K the XAO analysis revealed clearly that the order of the energy levels of 4f(j = 5/2)Γ8 and Γ7 states reversed again and is the same as that at room temperature. It also limited the possible 5d configurations to three models among the nine possible ones. However, the XAO analysis could not decide which of the three models was the best with the present accuracy of the measurement. Two of them have partially and fully occupied 5d(j = 5/2)Γ7 orbitals and the remaining one has a fully occupied 5d(j = 3/2)Γ8 orbital. Since the lobes of 5d(j = 3/2)Γ8 or 5d(j = 5/2)Γ7 orbitals do not overlap with the 4f(j = 5/2)Γ8 orbitals as well as the 5d(j = 5/2)Γ8 orbitals, the order of the energy levels of the 4f(j = 5/2) orbitals became the same as that at room temperature. These results indicate that the crystal field varies with temperature due to the electron transfer from B 2p to Ce 5d orbitals. The difference densities after the spherical-atom refinement at the three temperatures clearly revealed the different combinations of 4f and 5d orbitals which are occupied. In the present study positive peaks due to the 4f electrons appear near the Ce nucleus and those due to 5d orbitals are found in the area outside the 4f peaks. Between the two areas there is a negative area distributed spherically at 340 K. The negative area produced by the contraction of 4f(j = 5/2)Γ8 orbitals seems to reduce the electron repulsion of the 5d(j = 5/2)Γ8 orbitals and helps the 4f(j = 5/2)Γ8 orbitals to remain as the ground state.

Galvanic Corrosion between Magnesium Alloys and Steel

2013 ◽  
Vol 765 ◽  
pp. 648-652 ◽  
Author(s):  
Justyna Janiec-Anwar ◽  
George E. Thompson ◽  
Xiao Rong Zhou ◽  
Michele Curioni ◽  
Mark Turski ◽  
...  
Keyword(s):  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Pure Magnesium ◽  
Corrosion Morphology ◽  
Sodium Chloride Solutions ◽  
Alloy Type ◽  
Potentiodynamic Polarisation ◽  
The Individual ◽  
Coupling Current

The corrosion behaviour of pure magnesium, cast Elektron 21-T6, and extruded Elektron 43-T5, galvanically coupled to mild steel, has been investigated. The coupling current and potential were measured in selected concentrations of sodium chloride solutions in order to establish the effects of the environment and the alloy type on the galvanic corrosion behaviour. The time evolution of the galvanic currents was related to the results of potentiodynamic polarisation and to the corrosion morphologies revealed on specimens comprising a steel bolt and washer after salt spray testing. During the galvanic coupling, the measured current for pure magnesium was less than that for Elektron 21; the highest current was measured for Elektron 43, suggesting the highest corrosion rate. These results were in agreement with the behaviour expected from the individual potentiodynamic polarisation curves. Concerning the corrosion morphology of the galvanic couple, for Elektron 43, the corrosion close to the washer was relatively deep but extended only about 10 mm. For Elektron 21, the corrosion was shallower but advanced further (up to 15 mm). For pure magnesium, a relatively deep and laterally spread attack (approximately 20 mm around the bolt) was developed. These results suggest differences between observed corrosion in galvanically coupled assemblies and corrosion rates expected based on coupling currents alone.

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