Relation between Surface Tension and Graphite Shape in Cast Iron

Shi, Daming; Li, D.; Gao, Guanjun; Wang, L.

doi:10.2320/matertrans.mrp2008165

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…Thus, it may work as either an oxidizer or reducer. In particular, the shape of the graphite plays an important role in its mechanical characterization [2]. Graphene, in its role as a unit cell of graphite, is known to have great potential for applications in many fields [3].…”

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confidence: 99%

A simple method to determine the surface energy of graphite

Lee¹,

Lee²

2017

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Graphite is a material condensed from aromatic hydrocarbon that forms an infinite plane that exhibits an amphoteric feature. Structurally, a number of benzene rings form a solid planar sheet. A number of layers are formed from numerous unit cells, a so-called grapheme. A graphene sheet has an electron structure, which expands π-electrons into a two dimensional space. Graphite has AB-stacked bilayers of graphene. Because the interaction between two sheets is weak, their electronic structure may vary significantly. In addition, because graphite has either zero-semiconductor electronic structures, or a semi-metal electronic structure, its ionization energy is 4 eV [1] and it has dual electronic characteristics. Thus, it may work as either an oxidizer or reducer. In particular, the shape of the graphite plays an important role in its mechanical characterization [2]. Graphene, in its role as a unit cell of graphite, is known to have great potential for applications in many fields [3]. It is critical to understand graphite's interfacial interaction with a matrix, or its wettability, when applying its electrically and thermally conductive properties to characteristic composites.In this study, we proposed a simple method by which to determine the surface energy of graphene to expand graphite applications and to understand better the interfacial interaction of various matrices. This will explain why strong acids (e.g., sulfuric acid and nitric acid [4][5][6][7]) are employed for graphene or graphene oxide synthesis. In order to implement these kinds of experiments, repetitive work and trial-and-error are unavoidable. However, if we are able to understand the surface energy of graphite, we can save time and effort as well as facilitate systematic approaches by which we can choose appropriate solvents and chemicals.The surface energy could be represented in terms of wettability and contact angles. Wettability plays a key role in various industrial applications (e.g., material dispersion and interfacial chemistry). In particular, it significantly affects the coating industry, which includes nano engineering, ink, paint, paste, and adhesives; as well as the compound industry, which includes extrusion, injection molding, and casting [8][9][10][11][12][13]. Surface energy is the energy created by surface atoms, and is the result of the force of attraction they exert on external materials. Higher surface energy promotes greater liquid wettability. Therefore, the higher the surface energy is, the more enhanced the wettability, and the smaller the contact angle, becomes. As a result, knowing the droplet contact angle will determine the corresponding surface energy. The density of surface energy for water is 72 mJ/m 2 and its surface tension is 72 mN/m. Their values are the same. In order to measure the droplet contact angle, a planar surface and knowledge of the compact density of the given materials are required. In the case of graphite, it is difficult to acquire a planar surface. However, in this study, we report a simple meth...

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confidence: 99%

A simple method to determine the surface energy of graphite

Lee¹,

Lee²

2017

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“…A lower interfacial energy between graphite and melt is present in LGI than SGI, with CGI intermediate between the two. 18,30 This contributes to graphite being the leading phase during the eutectic formation of LGI, as the graphite is not significantly hindered by the surface energy when growing in to the melt. The lower interfacial energy found in LGI is caused by surface active elements (mainly S and O), which are not present to the same extent in CGI and SGI.…”

Section: Introductionmentioning

confidence: 98%

Literature review of microstructure formation in compacted graphite Iron

König

2010

International Journal of Cast Metals Research

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The literature concerning microstructure formation in compacted graphite iron is reviewed. Compacted graphite iron has an intermediate graphite morphology between lamellar graphite iron and spheroidal graphite iron. The formation of compacted graphite morphology is controlled by small changes in alloy composition. Several important factors influencing the formation of the as solidified microstructure, as well as the microstructure formation during the eutectoid transformation are also reviewed. The focus of this review is to compare mechanisms in which compacted graphite iron differs from lamellar graphite iron and spheroidal graphite iron. The effects of microstructure on some properties that are relevant in commercial applications are included in the study. Additionally the relatively few models for microstructure formation are also summarised.

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“…Data of the surface tension of cast iron have been proven experimentally, and values between 990 and 1465 mN m 21 are obtained as a result of its relationship with the graphite shape. 25 The empirical methodology to the iron stream shape was applied on real images from the optical sensing system on a foundry. This system is used to late-steam iron inoculation and also to visual inspection of the continuous casting flow rate by manual control of the stopper rod elevation.…”

Section: Casting Iron Stream Characterization: Practice Developmentmentioning

confidence: 99%

An empirical methodology for prediction of shape and flow rate of a free-falling non-submerged liquid and casting iron stream

Gamez-Montero

Castilla

Freire

et al. 2016

Advances in Mechanical Engineering

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The work presented in this article demonstrates the use of an empirical and simplified approach based on an optical technique and a home-made ad hoc code that give knowledge of the shape and falling velocity of a free-falling non-submerged liquid stream to predict its typology and flow rate. The visualization photographic technique is a non-intrusive robust technique which can be applied to high-temperature liquids in harsh environments, such as an iron stream in a foundry. This technique allows predicting the liquid stream boundaries and contours without any type of treatment on the fluid. As a result of employing this empirical methodology, three flow typologies for a water stream are proposed and demonstrated experimentally. Comparisons with experimental data reveal satisfactory estimations of mean flow quantities. Finally, the approach used based on experimental visualization is carried out in an iron stream of a foundry, not being disruptive to in-situ foundry operations and showing its potential to improve performance of the cast parts' properties during the casting phase and revealing to be a useful tool for process optimization.

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Relation between Surface Tension and Graphite Shape in Cast Iron

Cited by 6 publications

References 21 publications

A simple method to determine the surface energy of graphite

A simple method to determine the surface energy of graphite

Literature review of microstructure formation in compacted graphite Iron

An empirical methodology for prediction of shape and flow rate of a free-falling non-submerged liquid and casting iron stream

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