Jie Song, Qing Lian Li, Jun Sun, Xin Lin Liu, Lan Wei Chen
For LOX/LCH4 variable thrust rocket engine, the propellant methane is traditionally selected as the coolant in regenerative cooling channel (RCC). With the decrease of engine thrust, the mass flow rate of coolant methane decreases gradually. At low engine thrust, the coolant methane is usually in a subcritical state. The heat transfer deterioration of subcritical methane occurs in RCC, which may cause thrust chamber wall ablation. The two-phase pressure drop data of methane are crucial parameters for the design and optimization of RCC. But it is rarely to find such measured frictional pressure drop data of methane in open published literature. The two-phase pressure drop of methane during flow boiling in the single mini channels with the diameters of 2.0 mm are investigated systematically. Effects of the mass flux (582.19~1755.48 kg/m2·s), inlet pressure (0.56~3.55 MPa), heat flux (53.25~318.68 kW/m2) on the frictional pressure drop of methane are discussed. The results show that the frictional pressure drop of methane during flow boiling increases with mass flux and inlet pressure at the experimental conditions, and heat flux shows weak effect on the frictional pressure drop. The comparisons of the experimental data with the predicted value by existing six correlations are analyzed. Contrary to the conventional channels, homogeneous model yields better prediction than five separated flow models. Present experimental results can provide reference for the design and optimization of RCC in LOX/LCH4 rocket engine.
{"title":"Study on Two-Phase Pressure Drop of Methane during Flow Boiling in Mini Channel","authors":"Jie Song, Qing Lian Li, Jun Sun, Xin Lin Liu, Lan Wei Chen","doi":"10.4028/p-3yYkrV","DOIUrl":"https://doi.org/10.4028/p-3yYkrV","url":null,"abstract":"For LOX/LCH4 variable thrust rocket engine, the propellant methane is traditionally selected as the coolant in regenerative cooling channel (RCC). With the decrease of engine thrust, the mass flow rate of coolant methane decreases gradually. At low engine thrust, the coolant methane is usually in a subcritical state. The heat transfer deterioration of subcritical methane occurs in RCC, which may cause thrust chamber wall ablation. The two-phase pressure drop data of methane are crucial parameters for the design and optimization of RCC. But it is rarely to find such measured frictional pressure drop data of methane in open published literature. The two-phase pressure drop of methane during flow boiling in the single mini channels with the diameters of 2.0 mm are investigated systematically. Effects of the mass flux (582.19~1755.48 kg/m2·s), inlet pressure (0.56~3.55 MPa), heat flux (53.25~318.68 kW/m2) on the frictional pressure drop of methane are discussed. The results show that the frictional pressure drop of methane during flow boiling increases with mass flux and inlet pressure at the experimental conditions, and heat flux shows weak effect on the frictional pressure drop. The comparisons of the experimental data with the predicted value by existing six correlations are analyzed. Contrary to the conventional channels, homogeneous model yields better prediction than five separated flow models. Present experimental results can provide reference for the design and optimization of RCC in LOX/LCH4 rocket engine.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrogen is an impurity that is often present in LiXO3 (X= Nb, Ta) single crystals and related materials. In this context, the diffusion of hydrogen is an important process because it may influence the overall conductivity of the material. We investigated the diffusional hydrogen uptake in LiNb0.15Ta0.85O3 single crystals at 600 °C. For the experiments, O2 is bubbled through liquid deuterated water (D2O), which leads to a saturation of the gas atmosphere with D2O that is incorporated into the crystal during isothermal annealing. The diffusivities of deuterium during uptake were determined by infra-red spectroscopy. We identified a fast process that can be associated with tracer diffusion and a second slower process with an almost three times lower diffusivity.
{"title":"Experiments on Hydrogen Uptake and Diffusion in LiNb0.15Ta0.85O3 Single Crystals by Infra-Red Spectroscopy","authors":"C. Kofahl, Steffen Ganschow, Harald Schmidt","doi":"10.4028/p-2J7FpE","DOIUrl":"https://doi.org/10.4028/p-2J7FpE","url":null,"abstract":"Hydrogen is an impurity that is often present in LiXO3 (X= Nb, Ta) single crystals and related materials. In this context, the diffusion of hydrogen is an important process because it may influence the overall conductivity of the material. We investigated the diffusional hydrogen uptake in LiNb0.15Ta0.85O3 single crystals at 600 °C. For the experiments, O2 is bubbled through liquid deuterated water (D2O), which leads to a saturation of the gas atmosphere with D2O that is incorporated into the crystal during isothermal annealing. The diffusivities of deuterium during uptake were determined by infra-red spectroscopy. We identified a fast process that can be associated with tracer diffusion and a second slower process with an almost three times lower diffusivity.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Saidi, M.A. Djema, K. Hamouda, S. Abdi, M. Bouaziz
Tribofinishing is a mechanical-chemical process that utilizes low-frequency vibrations in the presence of abrasives and chemical additives. This process is primarily dependent on frequency and amplitude, which generally leads to improvements in characteristics, mechanical properties, physical attributes, and metallography of the treated surfaces. This document examines the influence of abrasives, specifically bakelites used as unguided cutting tools, on the wear resistance of AISI 1010 carbon steel. It takes into account the variation of influential parameters, namely frequency, amplitude, and treatment duration. The use of Minitab version 16 software enabled us to statistically analyze and interpret the obtained results, both numerically and graphically. This analysis also allowed us to determine the order and degree of influence of the factors on the response. The obtained results are highly interesting. The coefficient of friction decreased significantly with an increase in the treatment time, up to 90 minutes, while maintaining a frequency of up to 90 Hz and a maximum amplitude of 5 mm.
{"title":"Contribution to the Improvement of the Wear Resistance of the AISI 1010 Material by the Tribofinishing Process Using the Box-Behnken Experimental Designs","authors":"D. Saidi, M.A. Djema, K. Hamouda, S. Abdi, M. Bouaziz","doi":"10.4028/p-W1ujm5","DOIUrl":"https://doi.org/10.4028/p-W1ujm5","url":null,"abstract":"Tribofinishing is a mechanical-chemical process that utilizes low-frequency vibrations in the presence of abrasives and chemical additives. This process is primarily dependent on frequency and amplitude, which generally leads to improvements in characteristics, mechanical properties, physical attributes, and metallography of the treated surfaces. This document examines the influence of abrasives, specifically bakelites used as unguided cutting tools, on the wear resistance of AISI 1010 carbon steel. It takes into account the variation of influential parameters, namely frequency, amplitude, and treatment duration. The use of Minitab version 16 software enabled us to statistically analyze and interpret the obtained results, both numerically and graphically. This analysis also allowed us to determine the order and degree of influence of the factors on the response. The obtained results are highly interesting. The coefficient of friction decreased significantly with an increase in the treatment time, up to 90 minutes, while maintaining a frequency of up to 90 Hz and a maximum amplitude of 5 mm.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering that velocity of diffusion in a system solute-porous material-solvent depends on several factors, (among them, the concentration differential between “solute” in the porous material and “solute” in the solvent) the diffusion process will finish only when maximum entropy is achieved. Thus, the solute concentration will be equal in the matrix and in the solvent (equilibrium concept). On the other hand, if the velocity of diffusion depends on the differential of concentration, then, the amount of materials transferred per time unit (diffusion rate) will diminish as the process goes on. Moreover, when the final concentration of solute in the porous material is desired to be lower than that of the one-stage-equilibrium, then n-more stages must be added. Thus, the decision to choose a process with one or more stages, as well as the end point in each stage (as close or as far as equilibrium) will determine processing time and the use of other resources, i.e. amount of solvent, installation size, financial investment and so on. Therefore, the objective of this study is to develop a tool that helps to optimize these decisions by using a numerical approach.
考虑到溶质-多孔材料-溶剂系统中的扩散速度取决于多个因素（其中包括多孔材料中的 "溶质 "和溶剂中的 "溶质 "之间的浓度差），扩散过程只有在达到最大熵时才会结束。因此，基质和溶剂中的溶质浓度将相等（平衡概念）。另一方面，如果扩散速度取决于浓度差，那么单位时间内的物质转移量（扩散速率）将随着过程的进行而减少。此外，如果希望多孔材料中溶质的最终浓度低于一级平衡时的浓度，则必须增加 n 级。因此，选择一个或多个阶段的工艺，以及每个阶段的终点（接近或远离平衡），将决定处理时间和其他资源的使用，即溶剂量、安装规模、资金投入等。因此，本研究的目标是开发一种工具，利用数值方法帮助优化这些决策。
{"title":"Optimizing Diffusion Time and other Resources by Using the Diffusion Rate and Number of Stages Concepts","authors":"F. E. Carvajal-Larenas","doi":"10.4028/p-s1EZrY","DOIUrl":"https://doi.org/10.4028/p-s1EZrY","url":null,"abstract":"Considering that velocity of diffusion in a system solute-porous material-solvent depends on several factors, (among them, the concentration differential between “solute” in the porous material and “solute” in the solvent) the diffusion process will finish only when maximum entropy is achieved. Thus, the solute concentration will be equal in the matrix and in the solvent (equilibrium concept). On the other hand, if the velocity of diffusion depends on the differential of concentration, then, the amount of materials transferred per time unit (diffusion rate) will diminish as the process goes on. Moreover, when the final concentration of solute in the porous material is desired to be lower than that of the one-stage-equilibrium, then n-more stages must be added. Thus, the decision to choose a process with one or more stages, as well as the end point in each stage (as close or as far as equilibrium) will determine processing time and the use of other resources, i.e. amount of solvent, installation size, financial investment and so on. Therefore, the objective of this study is to develop a tool that helps to optimize these decisions by using a numerical approach.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a numerical study of fluid flow through perforated panels with square holes and open-cell material with cubic cells is presented. Structures with a wide variety of porosities (0.15<φ<0.94) and Reynolds numbers (0.01
{"title":"CFD Analysis of Perforated Plates and Open-Cell Materials Aerodynamics","authors":"Antonio F. Miguel","doi":"10.4028/p-O0aFG5","DOIUrl":"https://doi.org/10.4028/p-O0aFG5","url":null,"abstract":"In this paper, a numerical study of fluid flow through perforated panels with square holes and open-cell material with cubic cells is presented. Structures with a wide variety of porosities (0.15<φ<0.94) and Reynolds numbers (0.01<Re<6000) are studied. Among the various outcomes obtained, the results indicate that pressure gradient vs Reynolds number exhibits three different forms of variation, including linear (Re<1), nonlinear (1≤Re<4000), and one where the pressure gradient is virtually constant with the Reynolds number (Re≥4000). The results were provided in terms of loss factor, but also of intrinsic permeability and the Forchheimer coefficient. Relationships that connect porosity to the loss factor, intrinsic permeability, and Forchheimer coefficient are also presented. These findings may prove useful in better understanding the flow behaviors in perforated panels and cell metal foams, which have a wide range of applications.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In view of the fact that X-ray sources present characteristic spectra that make them unique, the spectral fitting technique has proven to play a fundamental role through the use of models that make it possible to reproduce the observed spectrum, thus making it possible to characterize the type of source that gave rise to it. A tool of paramount importance, among others that are currently gaining ground, is the XSPEC software, which is a solid and stable spectral fitting package that allows us to conduct scientific work with high standards of rigor in the analysis of data from astronomical objects in whose processes high energies are intrinsically involved, as is the case of X-rays. In this work we fit and analyze experimental data of two X-ray binary spectra: Cyg X-1 and V 0332+53, with theoretical models in XSPEC to obtain the expected statistics of the best fit through the reduced chi-square (hereafter, χ2) in both astronomical sources. From the results, it can be concluded that in both sources the best fit representing the physical processes occurring in these binaries was achieved, very close to results obtained by other authors using different techniques, contributing to the state of the art of the spectrum of astrophysical processes of high energy binaries.
鉴于 X 射线源呈现的特征光谱使其独一无二，光谱拟合技术已被证明发挥了重要作 用，通过使用模型可以再现观测到的光谱，从而可以确定产生光谱的源的类型。XSPEC 软件是一个极其重要的工具，也是目前越来越流行的工具之一，它是一个坚实稳定的光谱拟合软件包，使我们能够以高标准的严谨态度开展科学工作，分析来自天体的数据。在这项工作中，我们用 XSPEC 中的理论模型拟合和分析了两个 X 射线双星光谱的实验数据：Cyg X-1 和 V 0332+53，通过缩小的奇偶方差（以下简称为 χ2）获得了这两个天文来源的预期最佳拟合统计量。从结果中可以得出结论，在这两个来源中都实现了代表这些双星中发生的物理过程的最佳拟合，与其他作者使用不同技术获得的结果非常接近，从而为高能双星天体物理过程光谱的最新技术水平做出了贡献。
{"title":"Astrophysics of X-Ray Binary Spectra","authors":"Leticia Corral Bustamante","doi":"10.4028/p-Sp3C6x","DOIUrl":"https://doi.org/10.4028/p-Sp3C6x","url":null,"abstract":"In view of the fact that X-ray sources present characteristic spectra that make them unique, the spectral fitting technique has proven to play a fundamental role through the use of models that make it possible to reproduce the observed spectrum, thus making it possible to characterize the type of source that gave rise to it. A tool of paramount importance, among others that are currently gaining ground, is the XSPEC software, which is a solid and stable spectral fitting package that allows us to conduct scientific work with high standards of rigor in the analysis of data from astronomical objects in whose processes high energies are intrinsically involved, as is the case of X-rays. In this work we fit and analyze experimental data of two X-ray binary spectra: Cyg X-1 and V 0332+53, with theoretical models in XSPEC to obtain the expected statistics of the best fit through the reduced chi-square (hereafter, χ2) in both astronomical sources. From the results, it can be concluded that in both sources the best fit representing the physical processes occurring in these binaries was achieved, very close to results obtained by other authors using different techniques, contributing to the state of the art of the spectrum of astrophysical processes of high energy binaries.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ricardo Soares Gomez, Kelly C. Gomes, José Maurício Alves de Matos Gurgel, Fabio Emanuel França da Silva, Laís Belizário Alves, Hortência Luma Fernandes Magalhães, A.G. Barbosa de Lima
Sanitary ware, including toilets, washbasins, and bathtub, plays a crucial role in maintaining hygiene and sanitation in various settings. The drying process is a critical stage in the manufacturing of ceramic sanitary ware, as it influences product quality, production efficiency, and energy consumption. Then, the purpose of this work is to investigate the drying of sanitary ware at low temperature by experiments and empirical mathematical models. The idea is to accurately predict moisture loss of the ceramic parts under different operational conditions. Results of the drying kinetics have shown that higher temperatures and lower air relative humidity accelerate the drying process. Also, no cracks or fissures were observed as a result of drying sanitary ware at low temperatures and the two-term model provides the best fit for the dimensionless average moisture content as a function of the time. These findings contribute to a better understanding of the drying process and support the optimization of sanitary ware manufacturing.
{"title":"Drying of Industrial Sanitary Ware at Low Temperature: A Theoretical and Experimental Investigation","authors":"Ricardo Soares Gomez, Kelly C. Gomes, José Maurício Alves de Matos Gurgel, Fabio Emanuel França da Silva, Laís Belizário Alves, Hortência Luma Fernandes Magalhães, A.G. Barbosa de Lima","doi":"10.4028/p-Ghg2E8","DOIUrl":"https://doi.org/10.4028/p-Ghg2E8","url":null,"abstract":"Sanitary ware, including toilets, washbasins, and bathtub, plays a crucial role in maintaining hygiene and sanitation in various settings. The drying process is a critical stage in the manufacturing of ceramic sanitary ware, as it influences product quality, production efficiency, and energy consumption. Then, the purpose of this work is to investigate the drying of sanitary ware at low temperature by experiments and empirical mathematical models. The idea is to accurately predict moisture loss of the ceramic parts under different operational conditions. Results of the drying kinetics have shown that higher temperatures and lower air relative humidity accelerate the drying process. Also, no cracks or fissures were observed as a result of drying sanitary ware at low temperatures and the two-term model provides the best fit for the dimensionless average moisture content as a function of the time. These findings contribute to a better understanding of the drying process and support the optimization of sanitary ware manufacturing.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Advances in Mass and Thermal Transport in Engineering Materials IV","authors":"Andreas Öchsner, G. Murch, I. Belova","doi":"10.4028/b-bh2nvw","DOIUrl":"https://doi.org/10.4028/b-bh2nvw","url":null,"abstract":"","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this work is developing of the statistical model of hydrogen diffusion in the crystal lattice of BCC metals with an estimate of the contribution of quantum effects and deviations from the Arrhenius equation. The values of the statistical model calculations of H diffusion coefficients in Fe, V, Nb and Ta are in good agreement with the experimental data. The statistical model can also explain deviations from the Arrhenius equation at temperatures 300-500 K in Fe and Nb. The downward deviation of the diffusion coefficient at 300K can be explained by the fact that the statistical model does not consider the tunneling effect at temperatures below 300K. It was suggested that thermally activated fast tunnelling transition of hydrogen atoms through the potential barrier at temperatures below 500 K provides an almost free movement of H atoms in the α-Fe and V. Using the statistical model allows for the prediction of the diffusion coefficient for H in BCC metals at intermediate temperatures.
这项工作的目的是建立 BCC 金属晶格中氢扩散的统计模型，并估计量子效应的贡献和阿伦尼乌斯方程的偏差。统计模型计算出的铁、钒、铌和钽中的氢扩散系数值与实验数据十分吻合。统计模型还能解释铁和铌在温度 300-500 K 时与阿伦尼乌斯方程的偏差。300K 温度下扩散系数的向下偏差可以用统计模型没有考虑 300K 以下温度下的隧道效应这一事实来解释。据认为，在低于 500 K 的温度下，氢原子通过势垒的热激活快速隧穿转变提供了 H 原子在 α-Fe 和 V 中几乎自由的运动。
{"title":"Statistical Model of Hydrogen Diffusion in BCC Metals","authors":"Serhii Bobyr, J. Odqvist","doi":"10.4028/p-rbcq6Z","DOIUrl":"https://doi.org/10.4028/p-rbcq6Z","url":null,"abstract":"The purpose of this work is developing of the statistical model of hydrogen diffusion in the crystal lattice of BCC metals with an estimate of the contribution of quantum effects and deviations from the Arrhenius equation. The values of the statistical model calculations of H diffusion coefficients in Fe, V, Nb and Ta are in good agreement with the experimental data. The statistical model can also explain deviations from the Arrhenius equation at temperatures 300-500 K in Fe and Nb. The downward deviation of the diffusion coefficient at 300K can be explained by the fact that the statistical model does not consider the tunneling effect at temperatures below 300K. It was suggested that thermally activated fast tunnelling transition of hydrogen atoms through the potential barrier at temperatures below 500 K provides an almost free movement of H atoms in the α-Fe and V. Using the statistical model allows for the prediction of the diffusion coefficient for H in BCC metals at intermediate temperatures.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1%, freezing point equals -22°C, pH 6.5–7.5) at room temperature and 100°C. The average charges of copper, iron, and aluminium ions were calculated using Faraday’s law of electrolysis at electric current density 3,000 A/m2 (or 30 A/dm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100°C. The main condition was zAl=3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl=3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50%/50%) dissolve into the solution at temperature 100°C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100°C (and, obviously, up to 180°C) like “zeroth Arrhenius law”. The spherical anode effect is greater than the cylindrical anode effect in 1.5 times.
{"title":"Copper, Iron and Aluminium Electrochemical Corrosion Investigation during Electrolysis and Temperature Increasing","authors":"M. Yarmolenko, Sergii O. Mogilei","doi":"10.4028/p-5pUGB3","DOIUrl":"https://doi.org/10.4028/p-5pUGB3","url":null,"abstract":"An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1%, freezing point equals -22°C, pH 6.5–7.5) at room temperature and 100°C. The average charges of copper, iron, and aluminium ions were calculated using Faraday’s law of electrolysis at electric current density 3,000 A/m2 (or 30 A/dm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100°C. The main condition was zAl=3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl=3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50%/50%) dissolve into the solution at temperature 100°C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100°C (and, obviously, up to 180°C) like “zeroth Arrhenius law”. The spherical anode effect is greater than the cylindrical anode effect in 1.5 times.","PeriodicalId":11306,"journal":{"name":"Defect and Diffusion Forum","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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