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Detalles de la revista
Formato
Revista
eISSN
1804-1213
Publicado por primera vez
03 Apr 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

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Volumen 65 (2021): Edición 2 (September 2021)

Detalles de la revista
Formato
Revista
eISSN
1804-1213
Publicado por primera vez
03 Apr 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

4 Artículos
Acceso abierto

Characterization of bilayer (FeB/Fe2B) on AISI H13 work tool steel

Publicado en línea: 05 Oct 2021
Páginas: 40 - 48

Resumen

Abstract

In this work, the borided layers were produced on AISI H13 steel via solid boriding with a powders mixture containing 90 wt.% B4C and 10 wt.% NaBF4 for treatment times of 2-6 h at 900, 950 and 1000 °C. The microscopic observations revealed a less pronounced toothed interface between the borided layer and the transition zone. The XRD studies indicated the presence of a dual phase boride layer (FeB/Fe2B) besides the chromium and vanadium borides as precipitates inside it. The boronizing kinetics of AISI H13 steel was investigated by using the classical parabolic growth law. The obtained value of boron activation energy in the entire boride layer (FeB + + Fe2B) was found to be 236.34 kJ mol-1. Furthermore, this value of energy has been compared to the literature data. Finally, the nanohardness and reduced modulus of elasticity were measured for FeB, Fe2B and transition zone.

Acceso abierto

Simulation of the incubation time for the formation of (FeB/Fe2B) bilayer on pure iron

Publicado en línea: 05 Oct 2021
Páginas: 49 - 56

Resumen

Abstract

In this work, a mathematical model was used in order to study the growth kinetics of (Fe2B/FeB) bilayer during bori-ding process basing on the second Fick’s law and mass balance equation. The run of the numerical simulation allowed calculating the incubation time (τ) of each boronized layer (Fe2B or FeB), and estimating the effect of this parameter on the growth of the boronized layer. The boride incubation time for forming the FeB or Fe2B layer on the pure iron substrate was incorporated into the present mathematical model. To simulate the value of the growth rate constant and the incubation time for the bilayer configuration, the experimental data available in the literature concerning the boronizing of pure iron were considered. Based on the experimental and simulation results, it was shown that the incubation time decreases with increasing temperature in the FeB and Fe2B phases.

It was concluded from this study that the thickness of each boride layer depended on its growth rate constant and on another parameter kτ which was the rate constant of incubation time.The obtained results confirmed the validity of the present mathematical model and gave a good estimate of the incubation time during the formation of each boride layer as well as formulated the variation of this parameter with a mathematical equation. Furthermore, the comparison of experimental data with the simulated results of boronized layer thickness allowed to validate the present model.

Acceso abierto

Corrosion behaviour of the NiTiX (X = Si, Mg, Al) alloy prepared by self-propagating high-temperature synthesis

Publicado en línea: 05 Oct 2021
Páginas: 57 - 64

Resumen

Abstract

The NiTi alloys are used in the biomaterial field, because of their shape memory, superelasticity, and good corrosion resistance. The influence of alloying elements on the corrosion behaviour of NiTi was studied in this research. Samples were made by the self-propagating high-temperature synthesis method, milled, and then sintered by the spark plasma sintering method. Si, Mg, and Al were used as alloying elements always in 5 wt.%. Studied materials were compared with reference cast NiTi. Polarization resistance was measured after 1 and 12 hours of stabilization in phosphate-buffered saline. It was found out that alloying elements do not have a clear effect on polarization resistance. Si increased Rp and on the other hand, Al decreased it. Measurement of cyclic potentiodynamic polarization in PBS was conducted, too. All studied samples showed signs of localized corrosion. Corrosion was probably initiated in pores, which are presented on the surface due to used manufacturing technology.

Acceso abierto

Corrosion in underground infrastructures

Publicado en línea: 05 Oct 2021
Páginas: 65 - 69

Resumen

Abstract

There is a significant loss due to corrosion of buried infrastructure. Many pipes have failed due to mistreatment happening within them all around the world. Different soil aeration leads to macro corrosion cells that cause critical levels within the path corrosion leading to a loss of structural integrity of the buried pipes underground. This review paper seeks to address and presents a predetermined model developed by using software COMSOL Multiphysics to identify and characterize the areas experiencing a high rate of corrosion beneath the surface due to differential aeration. The pipe surfaces experience electrochemical reactions and reactant transport mechanisms in the soil and the pipes. Porosity and degree of saturation make the closed-form equations used to create the mass transport properties and electrical properties that constitute three-phase medium using standard soil parameters. The current model enables the study of soil property variations and conditions from the external environment pipeline corrosion. The model results conclude and agree well with the literature and case studies done at pipeline failure sites. The model used in this review will then enable water utilities to develop forecasting tools that may be useful for assessment.

4 Artículos
Acceso abierto

Characterization of bilayer (FeB/Fe2B) on AISI H13 work tool steel

Publicado en línea: 05 Oct 2021
Páginas: 40 - 48

Resumen

Abstract

In this work, the borided layers were produced on AISI H13 steel via solid boriding with a powders mixture containing 90 wt.% B4C and 10 wt.% NaBF4 for treatment times of 2-6 h at 900, 950 and 1000 °C. The microscopic observations revealed a less pronounced toothed interface between the borided layer and the transition zone. The XRD studies indicated the presence of a dual phase boride layer (FeB/Fe2B) besides the chromium and vanadium borides as precipitates inside it. The boronizing kinetics of AISI H13 steel was investigated by using the classical parabolic growth law. The obtained value of boron activation energy in the entire boride layer (FeB + + Fe2B) was found to be 236.34 kJ mol-1. Furthermore, this value of energy has been compared to the literature data. Finally, the nanohardness and reduced modulus of elasticity were measured for FeB, Fe2B and transition zone.

Acceso abierto

Simulation of the incubation time for the formation of (FeB/Fe2B) bilayer on pure iron

Publicado en línea: 05 Oct 2021
Páginas: 49 - 56

Resumen

Abstract

In this work, a mathematical model was used in order to study the growth kinetics of (Fe2B/FeB) bilayer during bori-ding process basing on the second Fick’s law and mass balance equation. The run of the numerical simulation allowed calculating the incubation time (τ) of each boronized layer (Fe2B or FeB), and estimating the effect of this parameter on the growth of the boronized layer. The boride incubation time for forming the FeB or Fe2B layer on the pure iron substrate was incorporated into the present mathematical model. To simulate the value of the growth rate constant and the incubation time for the bilayer configuration, the experimental data available in the literature concerning the boronizing of pure iron were considered. Based on the experimental and simulation results, it was shown that the incubation time decreases with increasing temperature in the FeB and Fe2B phases.

It was concluded from this study that the thickness of each boride layer depended on its growth rate constant and on another parameter kτ which was the rate constant of incubation time.The obtained results confirmed the validity of the present mathematical model and gave a good estimate of the incubation time during the formation of each boride layer as well as formulated the variation of this parameter with a mathematical equation. Furthermore, the comparison of experimental data with the simulated results of boronized layer thickness allowed to validate the present model.

Acceso abierto

Corrosion behaviour of the NiTiX (X = Si, Mg, Al) alloy prepared by self-propagating high-temperature synthesis

Publicado en línea: 05 Oct 2021
Páginas: 57 - 64

Resumen

Abstract

The NiTi alloys are used in the biomaterial field, because of their shape memory, superelasticity, and good corrosion resistance. The influence of alloying elements on the corrosion behaviour of NiTi was studied in this research. Samples were made by the self-propagating high-temperature synthesis method, milled, and then sintered by the spark plasma sintering method. Si, Mg, and Al were used as alloying elements always in 5 wt.%. Studied materials were compared with reference cast NiTi. Polarization resistance was measured after 1 and 12 hours of stabilization in phosphate-buffered saline. It was found out that alloying elements do not have a clear effect on polarization resistance. Si increased Rp and on the other hand, Al decreased it. Measurement of cyclic potentiodynamic polarization in PBS was conducted, too. All studied samples showed signs of localized corrosion. Corrosion was probably initiated in pores, which are presented on the surface due to used manufacturing technology.

Acceso abierto

Corrosion in underground infrastructures

Publicado en línea: 05 Oct 2021
Páginas: 65 - 69

Resumen

Abstract

There is a significant loss due to corrosion of buried infrastructure. Many pipes have failed due to mistreatment happening within them all around the world. Different soil aeration leads to macro corrosion cells that cause critical levels within the path corrosion leading to a loss of structural integrity of the buried pipes underground. This review paper seeks to address and presents a predetermined model developed by using software COMSOL Multiphysics to identify and characterize the areas experiencing a high rate of corrosion beneath the surface due to differential aeration. The pipe surfaces experience electrochemical reactions and reactant transport mechanisms in the soil and the pipes. Porosity and degree of saturation make the closed-form equations used to create the mass transport properties and electrical properties that constitute three-phase medium using standard soil parameters. The current model enables the study of soil property variations and conditions from the external environment pipeline corrosion. The model results conclude and agree well with the literature and case studies done at pipeline failure sites. The model used in this review will then enable water utilities to develop forecasting tools that may be useful for assessment.

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