Diffusion Foundations最新文献_第10页

Moisture Diffusion in Silica/Clay/Natural Rubber Hybrid Composites 二氧化硅/粘土/天然橡胶混合复合材料中的水分扩散

Diffusion Foundations Pub Date : 2019-05-01 DOI: 10.4028/www.scientific.net/DF.22.9

B. Pajarito, Mark Rigel R. Ali

{"title":"Moisture Diffusion in Silica/Clay/Natural Rubber Hybrid Composites","authors":"B. Pajarito, Mark Rigel R. Ali","doi":"10.4028/www.scientific.net/DF.22.9","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.22.9","url":null,"abstract":"This study investigated moisture diffusion in natural rubber (NR) hybrid composites filled with silica and bentonite clay. Natural bentonite (BNT) was treated with tetradecyldimethylammonium chloride and coco diethanolamide to produce modified bentonite (M-BNT). Varied proportions of silica, M-BNT, and BNT fillers were added to raw NR according to a third-degree simplex lattice mixture design of experiment. The addition of fillers affects the vulcanization characteristics, mechanical properties, and hardness of NR hybrid composites. Moisture diffusion behavior was studied by monitoring the water uptake of NR composites during immersion in deionized water at 80°C. Data from sorption experiments were fitted on the classical Fickian and Langmuir-type diffusion models. The Fickian model overestimates and underestimates the water uptake of NR composites in the early and later stages of moisture diffusion, respectively. On the other hand, the Langmuir-type model adequately captures the anomalous diffusion behavior of moisture in NR composites. Parameters of the Langmuir model (equilibrium water uptake and diffusion coefficient) vary with the composition of hybrid fillers. Optimum proportions of silica, M-BNT, and BNT in rubber composites were obtained by considering the effect of fillers on mechanical properties and moisture diffusion characteristics of NR.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132307729","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}

引用次数: 0

The Vacancy-Wind Factor and the Manning Factor Occurring in Interdiffusion and Ionic Conductivity in Solids 固体中相互扩散和离子电导率中的空风因子和曼宁因子

Diffusion Foundations Pub Date : 2019-05-01 DOI: 10.4028/www.scientific.net/DF.22.170

I. Belova, G. Murch

引用次数: 0

Ion Transport in Glass-Forming Calcium Potassium Nitrate: From Complex Behaviours to Unexpected Simplicities 形成玻璃的硝酸钙钾中的离子传输:从复杂的行为到意想不到的简单性

Diffusion Foundations Pub Date : 2019-05-01 DOI: 10.4028/www.scientific.net/DF.22.140

K. Funke, R. D. Banhatti, M. Ingram

{"title":"Ion Transport in Glass-Forming Calcium Potassium Nitrate: From Complex Behaviours to Unexpected Simplicities","authors":"K. Funke, R. D. Banhatti, M. Ingram","doi":"10.4028/www.scientific.net/DF.22.140","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.22.140","url":null,"abstract":"Re-examination of published conductivity spectra for 2Ca (NO3)2∙3KNO3 (CKN) in its molten and glassy states, in terms of the MIGRATION concept, has brought to light new links between elementary processes occurring within one picosecond and their successful outcomes, i.e. those which determine the DC conductivities. The starting point of this analysis is the transition at 378 K, which arises from a change from a decoupled to a coupled transport mechanism. Remarkably, while there is a change in the shape of the conductivity dispersion and a jump in its onset frequency, there is no change in the temperature dependence of DC conductivity. What emerges from the analysis is a surprising continuity in high-frequency behaviour, with the activation energy and volume for elementary displacements, Eed and Ved, remaining constant from 300 K in the glass up to 500 K in the melt. The ratio, Eed/Ved, turns out to be equal to our previously defined DC activation moduli for CKN, given by EDC(T)/VDC(T) and Tg/(dTg/dp) for charge transport in the melt and structural relaxation at Tg, respectively. It seems that, at very short times, molten CKN behaves just like an elastic solid. The importance of elastic forces for ionic transport in CKN is corroborated by the finding that the published value of the high-frequency shear modulus of glassy CKN, G¥, matches those of Eed/Ved and hence of both activation moduli. The detected continuity in the picosecond behaviour of CKN across the glass transition could provide a new link between fragile liquids and glassy materials in general.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120917785","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}

引用次数: 0

Hydrogen Distribution in Partly Desorbed MgH2 Samples 部分解吸MgH2样品中氢的分布

Diffusion Foundations Pub Date : 2019-05-01 DOI: 10.4028/www.scientific.net/DF.22.34

S. Lushnikov, T. V. Filippova, I. Bobrikov

引用次数: 0

Investigation of Interdiffusion in High Entropy Alloys: Application of the Random Alloy Model 高熵合金中相互扩散的研究:随机合金模型的应用

Diffusion Foundations Pub Date : 2019-05-01 DOI: 10.4028/www.scientific.net/DF.22.94

M. Afikuzzaman, I. Belova, G. Murch

{"title":"Investigation of Interdiffusion in High Entropy Alloys: Application of the Random Alloy Model","authors":"M. Afikuzzaman, I. Belova, G. Murch","doi":"10.4028/www.scientific.net/DF.22.94","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.22.94","url":null,"abstract":"High entropy alloys (HEAs) are composed of five or more principal elements with equal (or nearly equal) compositions. In this paper, interdiffusion phenomenon in the HEAs is investigated. Two composition dependent (as well as composition independent) interdiffusion matrices have been used for detailed studying of the diffusion behaviour in CoCrFeMnNi HEAs. These matrices are calculated according to the Darken and Manning formalisms and are used in combination with the explicit finite difference method (EFDM) to obtain interdiffusion profiles. First, the interdiffusion profiles are calculated for the case of the terminal binary diffusion couple. A significant difference in the composition profiles is found between predictions according to the Darken and Manning formalisms. Next, the interdiffusion problem in the 5-component alloy is addressed numerically by considering the interdiffusion coefficients as constant, independent of composition, in CoCrFeMnNi alloys for several diffusion couples (mainly quasi-binary and quasi-ternary). The simulated composition profiles are found to be in a very good agreement with the available experimental results [1, 2]. It should be pointed out that the independence on composition of the interdiffusion matrix should be used for diffusion couples under two conditions: relatively small changes in composition, and the non-zero/non-dilute terminal compositions. The composition dependent interdiffusion matrix should be used in the diffusion couple if the composition differences are large and/or zero/dilute terminal compositions. In this paper, the Darken and Manning formalisms are used for modelling the composition dependent interdiffusion matrices. The purpose of this modelling is to systematically investigate interdiffusion in CoCrFeMnNi alloys in diffusion couples with substantial changes in composition. The main application of the present research is in the prediction of possible interdiffusion profiles in the framework of the random alloy model.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121407302","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}

引用次数: 5

Mechanisms of Silicide Formation by Reactive Diffusion in Thin Films 薄膜中反应扩散形成硅化物的机理

Diffusion Foundations Pub Date : 2019-03-01 DOI: 10.4028/www.scientific.net/DF.21.1

D. Mangelinck

{"title":"Mechanisms of Silicide Formation by Reactive Diffusion in Thin Films","authors":"D. Mangelinck","doi":"10.4028/www.scientific.net/DF.21.1","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.21.1","url":null,"abstract":"Silicide formation by reactive diffusion is of interest in numerous applications especially for contact formation and interconnections in microelectronics. Several reviews have been published on this topic and the aim of this chapter is to provide an update of these reviews by focusing on new experiment results. This chapter presents thus some progress in the understanding of the main mechanisms (diffusion/reaction, nucleation, lateral growth…) for thin and very thin films (i.e. comprised between 4 and 50 nm). Recent experimental results on the mechanisms of formation of silicide are presented and compared to models and/or simulation in order to extract physical parameters that are relevant to reactive diffusion. These mechanisms include nucleation, lateral growth, diffusion/interface controlled growth, and the role of a diffusion barrier. The combination of several techniques including in situ techniques (XRD, XRR, XPS, DSC) and high resolution techniques (APT and TEM) is shown to be essential in order to gain understanding in the solid state reaction in thin films and to better control these reaction for making contacts in microelectronics devices or for other application.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127448454","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}

引用次数: 2

Diffusion Rates of Components in Metal-Silicides Depending on Atomic Number of Refractory Metal Component 金属硅化物中组分的扩散速率与难熔金属组分原子序数的关系

Diffusion Foundations Pub Date : 2019-03-01 DOI: 10.4028/www.scientific.net/DF.21.29

A. Paul

引用次数: 3

Diffusion-Limited Reactions of Non-Oxide Ceramics with Transition Metals 非氧化物陶瓷与过渡金属的扩散限制反应

Diffusion Foundations Pub Date : 2019-03-01 DOI: 10.4028/www.scientific.net/DF.21.85

A. Kodentsov

引用次数: 3

Periodic Layer Formation during Multiphase Diffusion in Silicide Systems 硅化物体系多相扩散过程中周期性层的形成

Diffusion Foundations Pub Date : 2019-03-01 DOI: 10.4028/www.scientific.net/DF.21.157

A. Kodentsov, J. Wojewoda-Budka, A. Wierzbicka-Miernik

{"title":"Periodic Layer Formation during Multiphase Diffusion in Silicide Systems","authors":"A. Kodentsov, J. Wojewoda-Budka, A. Wierzbicka-Miernik","doi":"10.4028/www.scientific.net/DF.21.157","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.21.157","url":null,"abstract":"Periodic layered morphology may occur during displacement solid-state reactions in ternary (and higher-order) silicide and other material systems. This periodic layered structure consists of regularly spaced layers (bands) of particles of one reaction product embedded in a matrix phase of another reaction product. The number of systems that is known to produce the periodic layered structure is rather small but increasing and includes metal/metal and metal/ceramic semi-infinite diffusion couples. The experimental results on different systems, where the periodic pattern formation has been observed are systematized and earlier explanations for this peculiar diffusion phenomenon are discussed. Formation of the reaction zone morphologies periodic in time and space can be considered as a manifestation of the Kirkendall effect accompanying interdiffusion in the solid state. The patterning during multiphase diffusion is attributed to diverging vacancy fluxes within the interaction zone. This can generate multiple Kirkendall planes, which by attracting in situ-formed inclusions of “secondary-formed phase” can result in a highly patterned microstructure.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131053668","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}

引用次数: 2

Oxidation Behavior of Silicides 硅化物的氧化行为

Diffusion Foundations Pub Date : 2019-03-01 DOI: 10.4028/www.scientific.net/DF.21.127

R. Mitra

{"title":"Oxidation Behavior of Silicides","authors":"R. Mitra","doi":"10.4028/www.scientific.net/DF.21.127","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.21.127","url":null,"abstract":"The oxidation behavior of Mo, Nb, and Ti-silicides has received significant attention in past few decades for their potential to be used as high temperature structural materials. These Si-bearing intermetallic alloys have the ability to form an oxide scale containing SiO2, which is protective if formed as a continuous and impervious layer, so that the ingress of oxygen from atmosphere to the underneath alloy is restricted. To form a continuous and stable SiO2 scale, it is important to have sufficient activity of Si along with thermodynamic and kinetic conditions favoring its growth in comparison to that of oxides of other alloying elements. MoSi2 has superior oxidation resistance compared to that of Mo3Si or Mo5Si3, because of its higher Si content. Furthermore, a continuous film of SiO2 is able to form at temperatures in the range of 800-1700 oC on MoSi2 due to vaporization of MoO3, but not on NbSi2 or TiSi2 due to competitive growth of Nb2O5 or TiO2, respectively. During past two decades, a significant effort has been devoted to development of Mo-Si-B alloys containing Mo-rich solid solution, Mo3Si and Mo5SiB2 as constituent phases, due to their ability to form a protective borosilicate scale. The presence of B2O3 contributes to fluidity of borosilicate scale, thereby contributing to closure of porosities. Efforts have been also made to develop multicomponent Nb-silicide based alloys with optimum combination of mechanical properties and high temperature oxidation resistance with limited success. There have been efforts to develop silicide based coatings for protection oxidation for Mo-rich Mo-Si-B alloys and Nb-Si based ternary or multicomponent alloys with inadequate oxidation resistance. Oxidation behavior of selected silicides with potential for structural application, along with mechanisms for protection against oxidation has been reviewed and discussed.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126440480","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}

引用次数: 4