scholarly journals Fundamental insights into the stabilisation and chemical degradation of the corrosion product scales

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Xiaoqi Yue ◽  
Lei Zhang ◽  
Yong Hua
Keyword(s):  
Corrosion Product ◽  
Atomic Level ◽  
Chemical Degradation ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Preferential Loss ◽  
Corrosion Scales ◽  
The Stability ◽  
Co Precipitation

AbstractCarbonate stability plays a crucial role in clarifying the evolution and protection of the naturally formed corrosion scales on the steel surface in the application of geothermal production. In this paper, the stability of the corrosion scales from both micro and atomic level are studied via a combination of electrochemistry, surface analysis and first-principle calculation. The chemical and physical characterisation of various iron–calcium mixed carbonates are experimentally analysed and results are compared with the first-principle calculation. In the presence of Ca2+, the preferential loss of Ca during the dissolution experiments was observed, the interactions within the crystal weaken where Ca2+ co-precipitation, confirmed by a faster degradation rate for Ca0.51Fe0.49CO3 than FeCO3. This work reveals the degradation and protection performance of the naturally formed carbonate layers and provides insights into understanding the corrosion product stability and chemical breakdown of the corrosion scales.

First-Principle Calculation for a Novel Hydrogen Storage Material Mg2Ni and its Substitutes

2013 ◽  
Vol 781-784 ◽  
pp. 19-23 ◽  
Author(s):  
Ying Liu ◽  
Ling Peng Meng ◽  
Shi Jun Zheng ◽  
Shao Wen Zhang
Keyword(s):  
Hydrogen Storage ◽  
Hydrogenation Reaction ◽  
First Principle ◽  
Practical Application ◽  
Hydrogen Storage Material ◽  
Storage Material ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Pseudopotential Theory ◽  
The Stability

A novel hydrogen storage material Mg2Ni has been studied by the first-principle methods based on plane-wave pseudopotential theory. The corresponding electronic structure of hydrogen storage materials, Mg2Ni, Mg12Ni5M1(M = Mn and Cu), and their hydride have also been investigated. The enthalpy of hydrogenation reaction is-65.07kJ/mol (H2), which is in line with the experimental results. The stability of the new hydride alloy increased by substitution with Cu, and a small amount of alternative might be preventing powdering after several cycles. The Mn atom substitutes Ni atom of hydride alloy which would weaken the H-Ni bond, and the temperature of desorption decreased. The results will play an important role in practical application.

A Method to Investigate Stability of Silicon Coating on Diamond Substrate by First Principle Calculation

2011 ◽  
Vol 175 ◽  
pp. 13-16
Author(s):  
Dong Xu Li ◽  
Jing Lu ◽  
Dong Li Yu
Keyword(s):  
Single Layer ◽  
Thermodynamic Temperature ◽  
First Principle ◽  
Simulation Data ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Diamond Substrate ◽  
Silicon Structures ◽  
Silicon Coating ◽  
The Stability

Diamond with inorganic coating such as silicon coatings was used to promote applications. Different kinds of silicon structures were found in the coatings. In this paper, first principle calculation was used to study the stability of cubic silicon and hexagonal silicon coatings deposited on diamond substrate. The simulation data suggest that the single layer hexagonal silicon coating form easily under low temperature due to the low lattice mismatching and thermodynamic temperature. However, the stronger bonding of Si-C bonds between substrate and coating direct the formation of cubic silicon coatings, as well as Si-Si bonds inner coatings, in agreement with experiments.

A combined study of thermodynamic and first-principle calculation for single bond energy of Cu clusters

2019 ◽  
Vol 125 (9) ◽  
pp. 094302
Author(s):  
H. Li ◽  
H. N. Du ◽  
X. W. He ◽  
Y. Y. Shen ◽  
H. X. Zhang ◽  
...  
Keyword(s):  
Bond Energy ◽  
First Principle ◽  
Single Bond ◽  
Principle Calculation ◽  
First Principle Calculation

First-Principle Calculation on Misfit Layered Cobaltite and La-Doped Series

2013 ◽  
Vol 652-654 ◽  
pp. 554-558
Author(s):  
Xin Min Min ◽  
Xuchao Wang
Keyword(s):  
Thermoelectric Property ◽  
Variation Method ◽  
First Principle ◽  
Direct Relation ◽  
Discrete Variation ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Binary Oxides ◽  
La Doped ◽  
Layered Cobaltite

The relations between electronic structure and thermoelectric property of misfit layered cobaltite of Ca3Co4O9 and La-doped series are studied from the calculation by density function and discrete variation method (DFT-DVM). The highest valence band (HVB) and the lowest conduction band (LCB) near Fermi level are only mainly from O 2p and Co 3d in Ca2CoO3 layer. Therefore, the semiconductor, or thermoelectric property of Ca3Co4O9 should be mainly from Ca2CoO3 layer, but have no direct relation to the CoO2 layer, which is consistent with that binary oxides hardly have thermoelectric property, but trinary oxide compounds have quite good thermoelectric property. With the amount of La-doped increase, the gap between HVB and LCB firstly decrease, then reaches the minimum, finally increase. The gap affects the thermoelectric property. Therefore, there is a best amount of Na-doped to improve thermoelectric property, which is consistent with the experiment.

First-Principle Calculation of Al2O3(012)/SiC(310) Interface Model

2017 ◽  
Vol 896 ◽  
pp. 120-127 ◽  
Author(s):  
Ting Ting Zhou ◽  
Chuan Zhen Huang ◽  
Ming Dong Yi
Keyword(s):  
Grain Boundary ◽  
Population Analysis ◽  
First Principle ◽  
Interface Model ◽  
Electronic Density ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Multi Phase ◽  
Relationship Of ◽  
Interface Bonding Strength

First-principle calculation is carried out on Al2O3(012)/SiC(310) interface model. It can be concluded from the electronic density and population analysis that Al-C and O-Si located at grain boundary primarily contribute to the interface bonding strength and creep resistance property. The electronic charges in grain boundaries and grains are compared with each other. And the valence electrons are found to be redistributed. The relationship of all kinds of chemical bonds in grains and grain boundary of the interface model is analyzed. Also the toughening mechanism of Al2O3/SiC multi-phase ceramic tool materials is explained in nano-scale.

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