Papers by Johan Deconinck
Corrosion Science, 2019
Highlights Calculation of all hydrogen trapping parameters made possible in all cases Assessi... more Highlights Calculation of all hydrogen trapping parameters made possible in all cases Assessing of the contribution given by the oxide layer at the exit side for each single experiment Still further investigation on deep traps needed
Lecture Notes in Engineering, 1992
To find primary current distributions, a lot of classical analytical tools are available (superpo... more To find primary current distributions, a lot of classical analytical tools are available (superposition, con- formal mapping, method of images, …) [15]. Once the geometry is too complex or when non-linear overpotentials are considered, approximate methods must be used.
Lecture Notes in Engineering, 1992
An electrochemical system consists in general of ionic solutions bounded by electrodes, membranes... more An electrochemical system consists in general of ionic solutions bounded by electrodes, membranes and insulators (fig. 1.1). At the electrodes electrochemical reactions take place. The flow of electrons in the outer circuit is converted into a flow of ions in the electrolyte.
Lecture Notes in Engineering, 1992
Much effort has been made to obtain a flexible general usable program. For that purpose a powerfu... more Much effort has been made to obtain a flexible general usable program. For that purpose a powerful data generator and postprocessor were developed.
Corrosion Science, 2015
The local concentration of dissolved oxygen over a metal-coated steel sample of cut-edge geometry... more The local concentration of dissolved oxygen over a metal-coated steel sample of cut-edge geometry was recorded by using either an amperometric probe or an optode (fibre-optic oxygen micro-sensor). Hydroxide ions, being the product of the current determining reaction on the amperometric micro-probe, were found to change the chemical composition of corrosion products. Application of an O 2 selective micro-optode for local measurements allows avoiding the indicated problem and is reported here for the first time when applied to localized corrosion measurements. The concentration of dissolved oxygen was mapped 100 lm above the cut-edge steel coated with Al-Zn-Mg alloy. This was performed quasi-simultaneously with rastering local current density and pH over the same sample area.
Simulation of Electrochemical Processes II, 2007
An inverted rotating disk electrode reactor (IRDE) is constructed to facilitate the study of elec... more An inverted rotating disk electrode reactor (IRDE) is constructed to facilitate the study of electrochemically formed gas bubbles. The hydrodynamic and mass transfer characteristics of this new cell design are validated by means of an electrochemical reaction with known characteristics, i.e. the ferri/ferro cyanide redox reaction. This validation is done both qualitatively and quantitatively. The qualitative validation consists of comparing the entire polarization curve obtained in the IRDE with the one obtained in the classical RDE setup under the same experimental conditions. To quantitatively validate the cell another approach was pursued. A previously developed statistically founded method to model an electrochemical system and to quantitatively determine its mass and charge transfer parameters is used. It is found that the mass and charge characteristics in both configurations agree very well.
The Journal of Physical Chemistry B, 2006
Strong electrolytes are described in the framework of the primitive model in which the solvent is... more Strong electrolytes are described in the framework of the primitive model in which the solvent is regarded as a dielectric continuum, using the mean spherical approximation. The analytical solution of the equilibrium and transport properties is dependent on the ions' diameters and valencies. For hydrated or nonspherical ions, an effective diameter must be fitted. A sensitivity study of the osmotic coefficient and the transport coefficients is performed on theoretical 1-1, 2-1, and 3-1 electrolytes, up to a total ion concentration of 2 mol/L.
Journal of Separation Science, 2009
The band broadening that can be expected in perfectly ordered cylindrical pillar arrays has been ... more The band broadening that can be expected in perfectly ordered cylindrical pillar arrays has been calculated for a wide range of intra-particle diffusion coefficients (D(sz)) and zone retention factors (0<k''<10) using an in-house-developed computational fluid dynamics-algorithm. Both pressure-driven and electrically driven (PD and ED) flows are considered. In the case of a large intra-pillar diffusion coefficient (D(sz)/D(mol)=0.5), the minimal reduced plate height varies between h=0.8 (low k'') and h=1.2 (high k''), while the C-term range of the Van Deemter curve depends only slightly on k''. In the case of a small intra-pillar diffusion coefficient (D(sz)/D(mol)=0.1), h is nearly independent of k'' and approximately equals h(min)=1.1, while the C-term band broadening decreases strongly with increasing k''. The difference between ED and PD flows in perfectly ordered porous pillar arrays is much smaller than in packed beds, generally only 3% difference around the minimum of the plate-height curve and maximally 10% at high-reduced velocities. The generated data sets were also ideal to verify the accuracy of k'' and D(sz) dependency of the general plate height model of chromatography. Determining the values of the geometrical parameters appearing in the model through curve fitting, the average fitting error can be reduced to a value of about 1%.
Journal of Nuclear Materials, 2009
The crack propagation rate of Type 316 stainless steel in boric acid-lithium hydroxide solutions ... more The crack propagation rate of Type 316 stainless steel in boric acid-lithium hydroxide solutions under PWR-relevant conditions was modelled. A film rupture/dissolution/repassivation mechanism is assumed and extended to cold worked materials by including a stress-dependent bare metal dissolution current density. The chemical and electrochemical conditions within the crack are calculated by finite element calculations, an analytical expression is used for the crack-tip strain rate and the crack-tip stress is assumed equal to 2.5 times the yield stress (plane-strain). First the model was calibrated against a literature published data set. Afterwards, the influence of various variables-dissolved hydrogen, boric acid and lithium hydroxide content, stress intensity, crack length, temperature, flow rate-was studied. Finally, other published crack growth rate tests were modelled and the calculated crack growth rates were found to be in reasonable agreement with the reported ones. Ó 2009 Elsevier B.V. All rights reserved. the calculation of the crack-tip electrode potential E tip and the crack-tip strain rate _ e. How CGR316BLi-calculates those is described in subsequent paragraphs. 3. The crack-tip strain rate In the CGR316BLi model the crack-tip strain rate is calculated analytically. Various formulae can be found for the crack-tip strain
Journal of Nuclear Materials, 2009
The chemical and electrochemical conditions within a crevice of Type 316 stainless steel in boric... more The chemical and electrochemical conditions within a crevice of Type 316 stainless steel in boric acidlithium hydroxide solutions under PWR-relevant conditions were modelled with a computational electrochemistry code. The influence of various variables: dissolved hydrogen, boric acid, lithium hydroxide concentration, crevice length, and radiation dose rate was studied. It was found with the model that 25 ccH 2 /kg (STP) was sufficient to remain below an electrode potential of-230 mV she , commonly accepted sufficient to prevent stress corrosion cracking under BWR conditions. In a PWR plant various operational B-Li cycles are possible but it was found that the choice of the cycle did not significantly influence the model results. It was also found that a hydrogen level of 50 ccH 2 /kg (STP) would be needed to avoid substantial lowering of the pH inside a crevice.
Journal of Materials Processing Technology, 2004
This paper proposes a general applicable numerical method for the simulation of 3D electrode shap... more This paper proposes a general applicable numerical method for the simulation of 3D electrode shape changes obtained during electrochemical machining processes based on the marker method. The electrode shape change is found by displacing each node ...
Journal of Electroanalytical Chemistry, 2001
A versatile model for the simulation of electrochemical processes at a rotating disc electrode is... more A versatile model for the simulation of electrochemical processes at a rotating disc electrode is presented. This model is based on the dilute solution ion model, in combination with an adequate description of electrode reaction kinetics. A brief introduction is given to the theoretical aspects of the model and the numerical solution technique being used to solve this model for
Journal of Electroanalytical Chemistry, 2008
... E-mail The Corresponding Author , Els Tourwé a , E-mail The Corresponding Author , Tom Breuge... more ... E-mail The Corresponding Author , Els Tourwé a , E-mail The Corresponding Author , Tom Breugelmans a , c , E-mail The Corresponding Author , Marnix Depauw a , E-mail The Corresponding Author , Johan Deconinck b , E-mail The Corresponding Author and Annick Hubin ...
Journal of Electroanalytical Chemistry, 1997
An analytical solution for the one-dimensional steady-state transport of ions in an electrolyte b... more An analytical solution for the one-dimensional steady-state transport of ions in an electrolyte between two planar electrodes has been obtained. This electrolyte contains one electroactive species and any number of non-reacting species. The mass and charge transport equations give rise to an implicit form of a set of non-linear algebr~c equations which must be solved numerically. It has been shown that the same set of equations, with only a very small modification, can easily be used to solve the stagnant boundary layer problem. The solution is generally applicable and can deal with any kind of overpotential relation at both anode and cathode. The analytical solution for the stagnant boundary layer has been used to determine the diffusion coefficient for the reacting ion and the kinetic parameters in the Buder-Volmer overpotential relation for the electrodeposition of copper from a 0.01 M CuSO4 + 0.1 M H2SO 4 solution. The resulting parameters are in good agreement with the values found in the literature. Analytical results obtained with these parameters match very well with the experimental data for current densities ranging from secondary up to limiting current values and for different values of the rotation speed (100, 500 and 1000revmin-t). Also, it has been shown that neglecting migration can lead to an overestimation of the diffusion coefficient of about 15%.
Journal of Computational Physics, 2010
ABSTRACT The article discusses components and performance of an algebraic multigrid (AMG) precond... more ABSTRACT The article discusses components and performance of an algebraic multigrid (AMG) preconditioner for the fully coupled multi-ion transport and reaction model (MITReM) with nonlinear boundary conditions, important for electrochemical modeling. The governing partial differential equations (PDEs) are discretized in space by a combined finite element and residual distribution method. Solution of the discrete system is obtained by means of a Newton-based nonlinear solver, and an AMG-preconditioned BICGSTAB Krylov linear solver. The presented AMG preconditioner is based on so-called point-based classical AMG. The linear solver is compared to a standard direct and several one-level iterative solvers for a range of geometries and chemical systems with scientific and industrial relevance. The results indicate that point-based AMG methods, carefully designed, are an attractive alternative to more commonly employed numerical methods for the simulation of complex electrochemical processes.
Journal of Applied Electrochemistry, 2009
Journal of Applied Electrochemistry, 2008
ABSTRACT
Electrochimica Acta, 2007
The influence of the fluid flow and the cell geometry on the deposition of copper on wires was st... more The influence of the fluid flow and the cell geometry on the deposition of copper on wires was studied numerically. A numerical method based on the system residual distribution schemes and the finite element method was developed to calculate the fluid flow and the mass transfer including the effects of diffusion, migration, convection, homogeneous reactions, turbulence and multiple electrode reactions
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Papers by Johan Deconinck