Modelling the Effect of Residual and Diffusion induced Stresses on Corrosion at the Interface of Coating and Substrate

CORROSION ◽  
10.5006/1804 ◽  
2015 ◽  
Author(s):  
Mian Nazir ◽  
Zulfiqar Khan ◽  
Adil Saeed ◽  
Keith Stokes
Keyword(s):  
Induced Stresses ◽  
And Diffusion

Thermal and diffusion‐induced stresses in crystalline solids

1995 ◽  
Vol 77 (1) ◽  
pp. 127-134 ◽  
Author(s):  
I. V. Belova ◽  
G. E. Murch
Keyword(s):  
Crystalline Solids ◽  
Induced Stresses ◽  
And Diffusion

scholarly journals Phase Field Modeling of Coupled Phase Separation and Diffusion-Induced Stress in Lithium Iron Phosphate Particles Reconstructed From Synchrotron Nano X-ray Tomography

2019 ◽  
Vol 16 (4) ◽  
Author(s):  
Linmin Wu ◽  
Vincent De Andrade ◽  
Xianghui Xiao ◽  
Jing Zhang
Keyword(s):  
Phase Separation ◽  
Phase Field ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
Ion Concentration ◽  
Concentration Difference ◽  
X Ray ◽  
Aspect Ratios ◽  
Induced Stresses ◽  
And Diffusion

In this study, the phase separation phenomenon and diffusion-induced stresses in lithium iron phosphate (LiFePO4) particles under a potentiostatic discharging process have been simulated using the phase field method. The realistic particles reconstructed from synchrotron nano X-ray tomography along with idealized spherical and ellipsoid shaped particles were studied. The results show that stress and diffusion process in particles are strongly influenced by particle shapes, especially at the initial lithiation stage. Stresses in the realistic particles are higher than that in the idealized spherical ones by at least 30%. The diffusion-induced hydrostatic stress has a strong relationship with lithium ion concentration. The hydrostatic stresses and first principal stresses tend to shift from lower values to higher values as the particle takes in more lithium ions. Additionally, the diffusion-induced stresses are related to the maximum concentration difference in the particle. High concentration difference will cause high stresses. In ellipsoid particles, the stress levels increase with the aspect ratios. The model provides a design tool to optimize the performance of cathode materials with phase separation phenomena.

Effect of Irreversible Electrochemical Reaction on Diffusion and Diffusion-Induced Stresses in Spherical Composition–Gradient Electrodes

2019 ◽  
Vol 75 (1) ◽  
pp. 55-63
Author(s):  
Kai Zhang ◽  
Bailin Zheng
Keyword(s):  
Electrochemical Reaction ◽  
Composition Gradient ◽  
Electrochemical Performances ◽  
Transition Form ◽  
Capacity Fading ◽  
Induced Stresses ◽  
The Difference ◽  
And Diffusion ◽  
Positive Effect ◽  
Heterogeneous Factor

AbstractComposition–gradient electrodes have been proved to have excellent electrochemical performances. The effect of irreversible electrochemical reaction on diffusion and diffusion-induced stresses in such electrodes is investigated. The diffusion equation and mechanical equation considering the electrochemical reaction and the heterogeneous factors are derived, and the distributions of lithium (Li) concentration and stresses in a spherical electrode are obtained under potentiostatic charging. The results indicate that the electrochemical reaction will slow down the diffusion process and enhance the stresses of the electrode. However, the heterogeneous factors of the electrochemical reaction could provide a positive effect on the stresses, which means that the heterogeneous factor is conducive to avoid capacity fading of the battery. The results suggest that the composition–gradient electrodes could be designed to have a decreasing transition form of forward reaction rate and an increasing transition form of the difference of atomic volume between reactants and the reaction product.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

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