Issue
Metall. Res. Technol.
Volume 119, Number 2, 2022
Article Number 208
Number of page(s) 8
DOI https://doi.org/10.1051/metal/2022020
Published online 11 March 2022

© EDP Sciences, 2022

1 Introduction

Mold fluxes have some good functions as in controlling the heat transfer, lubricating the strand shell, providing heat insulation, absorbing inclusions and securing the molten steel from oxidation [14]. Nowadays, fluorides, which promote the precipitation of Cuspidine [5], needs to be replaced since they induce some negative effects such as environment pollution and equipment corrosion in continuous casting process. Hence, the development of a highly efficient and environment friendly fluorine free mold flux should be indispensable [6,7].

Several oxides like Na2O, K2O, Li2O, TiO2 and B2O3 have been extensively implied to compensate the negative effects caused by the absence of fluorides [812]. As reported in many papers, B2O3 used to compensate the negative effects caused by the absence of fluorine, the modification of fluorine by B2O3 in mold fluxes would replace Cuspidine [12]. Even though the influences of B2O3 addition and basicity on the structure and property of CaO-SiO2-B2O3 slag have been investigated that various with slag composition range [13,14], the contradiction between lubrication and heat transfer of fluorine-free slag remains unresolved. Based on the diversity and complexity of mold fluxes components, the influence mechanisms of other components are still necessary to be explored to provide theoretical guidance for slag composition design and function exertion. Recently some studies regarding BaO were found that raising BaO content led to the development of a favorable crystalline phase, such as Ceslian (BaAl2Si2O8). Moreover, the viscosity, activation energy, melting temperature and breaking temperature of the samples decreased with the addition of BaO [15,16], because of the large size of Ba2+ cation [1719] could have a relatively low detrimental effect on the dielectric properties of the resulting glass-ceramic material [2022]. This means that BaO may play an imperative role in mold fluxes. Viscosity, as one of the macroscopic properties, which may vary with structure, plays an imperative role in continuous casting. Since the molecular mass of BaO is higher than CaO, the actual concentration of network modifiers decreases when an equal mass of CaO was substituted with BaO, which resulted in the decrease of the depolymerization of the slag structure, causing the increase in viscosity with the increase of BaO contents [17]. However, the effect mechanism of BaO on the structure and properties of slag is not very clear, especially, the relationship between composition, structure and properties of fluoride-free mold fluxes is almost a blank, it is of great significance to study the effect of BaO on the structure and viscosity of mold fluxes.

Herein, the influence of BaO content on structure and fluid behavior of CaO-SiO2-B2O3-based melts are investigated combing molecular dynamics (MD) simulation, rotary viscometer, spectral experiment and X-ray diffraction test in the present study.

2 Materials and methods

2.1 Molecular dynamic simulation

To study the effect of BaO content on the structure of mold flux, MD simulation has been carried out Materials Explorer program [23,24]. For MD simulation, it’s necessary to select potential function and its consequent parameters. Generally, the two-body Born-Mayer-Huggins (BMH) potential function has successfully been used in silica and silicate systems [2527], which included long-range Coulomb interactions, short-range repulsion interactions, and van der Waals forces; the BMH potential function is shown in equation (1).(1)

Here, Uij(r) is the interatomic-pair potential; qi and qj are the selected charges, which are generally equal to the standard valence of the atoms; rij represents the distance between ions i and j; Aij and Cij are energy parameters describing the repulsive and van der Waals attractive forces, respectively, and Bij is an e-folding length characterizing the radially symmetric decay of electron repulsion energy between atom pair ij. The potential parameters have three categories including force field, empirical and non-empirical parameters. Since the parameters of the silicate system have been well studied, empirical parameters were used in this paper [28]. Table 1 is the interaction potential parameters of particles in the melt.

The compositions of CaO-SiO2-B2O3-BaO system are shown in Table 2 based on phase diagrams [29,30] and the slag density can be calculated on the base of the empirical formula in the literature [31]. For quaternary systems, the total number of atoms in each cell was about 6000 and atoms are randomly placed in the cube simulation unit and periodic images are formed by using periodic boundary conditions. All simulations were performed in an NVT (constant number of particles, volume, and temperature) ensemble, which is used to maintain its stability, while the Parrinello-Rahman and Nosé methods are used to control temperature and pressure. In the algorithm, the truncation radius of the short-range force is set to be 10 Å, which is less than half the smallest of the edge length of any system cell. The Ewald summation method was used to calculate the long-range Coulomb force. The running time step is set to 1 fs and the frog-jump logarithm saves data every 10 steps. During the simulation process, the initial temperature was fixed at 3727 °C (4000 K), for 24,000 steps to agitate the atoms and reduce the effect of the initial distribution. Then, the temperature was reduced to 1300 °C (1573 K) by 96,000 steps. Finally, the structure information was obtained by relaxing 60,000 steps at 1300 °C (1573 K) in the equilibrium calculation.

Table 1

BMH potential parameters of atomic pairs in CaO-SiO2-B2O3-BaO melts.

Table 2

Composition content, atomic numbers, density and box length of CaO-SiO2-B2O3-BaO system at 1300 °C (wt%).

2.2 Viscosity measurement

In mold fluxes, viscosity is considered as an important property, which could affect the surface quality of the slab. In the current study, the viscosity measurements were carried out by using the rotating cylinder method with a Brookfield DV-II+ viscometer (Brookfield Inc., USA). Fluorine-free mold fluxes were designed based on the MD simulation and the compositions are shown in Table 3. The slag samples were prepared with pure chemical reagents CaCO3, BaCO3, SiO2, B2O3, Al2O3, MgO, Na2CO3, and Li2CO3.

The viscosity was characterized by the torque of a cylinder that rotated at a fixed speed in a graphite crucible filled with the liquid flux. The temperature was measured through a thermal couple contacted with the outside bottom of the crucible in the MoSi2 furnace, and the temperature in the crucible was calibrated before testing. When measuring the viscosity of those mold fluxes, first, about 250 g of the powders were placed in a graphite crucible with internal diameter of 50 mm and a height of 100 mm, respectively. Second, the crucible was heated to 1300 °C (1573 K) and held for 10 min to obtain a homogeneous melt. Then, the bob, which is made of molybdenum with a height of 18 mm and a diameter of 15 mm, was immersed into liquid slag bath and rotated at a fixed speed with 12 r/min [3234]. Each measurement was performed during the cooling process, and the data of viscosity v/s temperature were collected every 5 s.

Table 3

Composition content of fluorine-free mold fluxes (wt%).

2.3 FTIR spectroscopy

To study the microstructure of slag, it is necessary to test its melt state at high temperature. However, due to the limitations of experimental equipment and conditions, this paper adopts quenching method to quickly place the high-temperature slag of the components shown in Table 3 in liquid nitrogen, and allow them to rapidly cool down to obtain a glassy state, to keep the high-temperature molten structure approximately. The as-quenched samples were analyzed using FTIR (Nicolet 6700). Firstly, the slag cooled to a glassy state needs to be dried, crushed, and ground to 200 mesh or less. Then 1 mg of each sample was mixed with an appropriate amount of KBr and was pressed into a uniform transparent sheet for the FTIR test. The FTIR measurement was conducted by a spectrophotometer equipped with a KBr detector, and the spectra were recorded in the range of 2000 to 200 cm−1 with a resolution of 2 cm−1 [3537]. The wavenumber of the FTIR transmission spectra region of the samples is mainly between 1600 and 400 cm−1.

2.4 XRD experiment

XRD tests were carried out to verify the fully glassy state of the quenched sample. The samples subjected to crushing and grounding into powder samples, and then the phases of samples were analyzed by X-ray diffraction (XRD, Bruker D8 Advance, Cu target Kα radiation, λ = 1.54056 Å). The radiant tube voltage was 40 kV, the scanning rate was 2°/min, the scanning range was in the range of 100 to 800.

3 Results and discussion

3.1 Effect of BaO on the structure of the CaO-SiO2-B2O3-BaO based melts

3.1.1 Structure of the CaO-SiO2-B2O3-BaO quaternary system

(1) Average bond length and average coordination number

The curves of RDFs and CNs for Ca-O, Ba-O, Si-O, B-O and O-O of sample B1-1 as an example in CaO-SiO2-B2O3-BaO system were described in Figure 1.

As revealed from Figure 1, average bond length could be obtained by RDFs values that 2.30 Å, 2.25 Å, 1.61 Å, 1.36 Å and 2.64 Å were well matched with Ca-O, Ba-O, Si-O, B-O and O-O, respectively. With the addition of BaO content, no change was determined in the average bond length of Si-O, which was 1.61 Å matched well with literatures [38,39]. The order of the average bond length of O-O>Ca-O>Ba-O>Si-O>B-O. The order of average coordination numbers found from CNs curves Ba-O>Ca-O>O-O>Si-O>B-O were 7.53>6.42>6.27>4.18>3.56, respectively. The sharpness of the peaks revealed the stability between the atomic pairs, the peak of Si-O is sharper than Ba-O. Also studied by other researchers smoother and wider CN values exposed better stability between atoms [40].

(2) Distribution of oxygen and Qi species

In quaternary slag system, the network former connected with oxygen were exploited to analyze oxygen distribution within truncation radius. The network formers of an oxygen atom in the truncated radius indicated the oxygen atom assigned tri-coordinated oxygen Ot, bridge oxygen Ob, non-bridge oxygen Onb and free oxygen Of, if there were three network formers, two network formers, one network former and non-network former, respectively. Besides Onb, Ob and Ot could be further subdivided into different types of oxygens in multiple network formation system. In CaO-SiO2-B2O3-BaO quaternary slag system, Ob could be divided in three more sub types: Si-O-Si (SOS), Si-O-B (SOB) and B-O-B (BOB), while Onb were divided into two types: Ca/Ba-O-Si (OS) and Ca/Ba-O-B (OB). Since Ot was not found in CaO-SiO2-B2O3-BaO quaternary slag system, it indicates that there was no tri-coordinated oxygen in the slag to balance the negative excess of [BO4]5– tetrahedron.

From Figure 2, it was cleared with the increase of BaO content in slag at basicity of 1.15 and 1.25, the enhancement in the ratio of OSB and OSS was attained while the ratio of OS and OB was diminished as well unchanged Of ratio was designated. These results further confirmed the statement that replace of CaO by BaO in slag would improve the complexity of slag structure.

The structural unit Qi was accounted corresponding to the number of Ob connected to the network former within the truncation radius, where i denoted the number of bridging oxygens, and Q0, Q1, Q2, Q3 and Q4, correspond to island, dimers, ring or chain, slice or layer, three-dimensional frame or mesh tetrahedron, respectively. Since there were two kinds of networks formers Si and B in CaO-SiO2-B2O3-BaO slag system, the distribution of structural unit Qi was analyzed for Si and B respectively.

As described in Figure 3, Qi species for Si at basicity R = 1.15, the intensities of Q0, Q1 were increased first and then decreased, while Q2 was decreased and Q3, Q4 was found to increased smoothly. As in the case of R = 1.25, Q0, Q2 were increased first and then decreased while intensity of Q1 was decreased smoothly, although the intensity of Q3 and Q4 was increased efficiently. The above discussion regarding the increase in intensity of Q3 and Q4 revealed that the structure being complex and viscosity was increased.

Meanwhile, with the addition of BaO in melts, enhancement change in Qi species for B was found. When R = 1.15, the increment in the concentration of Q0, Q1 and Q3 was found in the start and then decreased slightly, while Q2 increased in the range of 0–15 wt% and then decreased from 15–20% and Q4 increased smoothly. In the case of R = 1.25, the intensities of Q0, Q1 were found to decrease while Q2 increased in the range of 0–5 wt% then decreased in the range of 5∼20 wt%, besides, smoothly increase was found for Q3 and Q4.

thumbnail Fig. 1

(a) Radial distribution function, and (b) average coordination number function of different atom pairs in sample B1-1.

thumbnail Fig. 2

Effect of BaO content on oxygen distribution in CaO-SiO2-B2O3-BaO system.

thumbnail Fig. 3

Effect of BaO content on structure unit Qi for Si and B in CaO-SiO2-B2O3-BaO system.

3.1.2 Structure of the CaO-SiO2-B2O3-BaO-based mold fluxes

As can be seen from Figure 4, there is no characteristic signal occurring in the samples with different basicity R = 1.15 and 1.125, which indicates they are fully amorphous and can represent for the structure of each molten mold flux.

As shown in Figure 5, the spectra of all the F-free glasses exhibited four broad transmittance bands in the range of 400–1600 cm−1. Thereinto, the bands in the region of 400–600 cm−1, 650–800 cm−1, 800–1200 cm−1, and 1300–1500 cm−1 were due to bending vibrations of Si-O-Si linkages [41], bending vibrations of the B-O-B bonds, stretching vibrations of the [SiO4]4– and [BO4]5– tetrahedron [4244], and B–O vibrations in [BO3]3– triangle [41], respectively.

According to the experimental results of FTIR, the peak intensities of all the glasses with basicity 1.15 and 1.25 were enhanced with the increase of BaO contents in the range of 5–20 wt%, signifying the polymerization of Si-O and B-O network [45]. The FTIR results matched well with the MD simulation results, that with the addition of BaO contents in mold fluxes, the structures of Si-O and B-O were more aggregated and the adjacent structural units were more closely connected, resulting in the complexity of the structure, which means the viscosity of mold fluxes with basicity of 1.15–1.25 would intensify.

thumbnail Fig. 4

XRD results of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

thumbnail Fig. 5

FTIR spectra of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

3.2 Effect of BaO on the fluid behavior of the mold flux

3.2.1 High temperature viscosity

As exposed from Figure 6, the viscosity at 1300 °C of fluorine-free mold fluxes intensified in the range of BaO = 5–20 wt%, this is mainly due to the complexity of the microstructure of the molten slag, which is consistent with the results of molecular dynamics simulation and infrared spectrum experiment. In the traditional CaO-SiO2 based mold flux with [SiO4]4– tetrahedron as the network framework, BaO partially replaces CaO, could reduce the viscosity of the slag to a small extent. This was because CaO and BaO are alkaline earth metal oxides, while the Ba2+ ion radius (1.45 Å) was larger than the Ca2+ ion radius (1.06 Å), and the electrostatic potential of Ba2+ was smaller than that of Ca2+ [1719]. So, BaO was easier to dissociate into O2–, which had a greater depolymerization effect on the Si-O network structure, thereby reducing the viscosity of traditional CaO-SiO2 based mold flux. However, within the range of the fluorine-free mold flux in this study, the high-temperature viscosity of the fluorine-free mold flux increased with the increase of BaO content, which was mainly determined by the competitive mechanism of the influence of BaO and B2O3 on the complexity of the slag structure. Since the fluorine-free mold flux contained a higher content of B2O3, BaO replaces CaO to increase the alkalinity of the slag, thereby providing more cations to balance the negative charge of [BO4]5– tetrahedron, making [BO3]3– trihedrons polymerize to [BO4]5– tetrahedrons, which made the melt structure more complicated and suggested to increase in viscosity on a macroscopic scale.

thumbnail Fig. 6

Effect of BaO content on viscosity at 1300 °C of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

3.2.2 Viscosity-temperature curve and activation energy

The viscosity-temperature curves in Figure 7 showed acidic slag characteristics, indicating that BaO replaced CaO to improve the glassiness of fluorine-free mold fluxes.

In the process of viscosity-temperature test, the viscosity of uniformity melts at high temperature obeys the motion law of Newtonian viscous liquid, in which the relationship between viscosity and temperature follows the Arrhenius equation [46].(2)where η is the viscosity, A is a constant dependent upon the slag structure, R is the gas constant and Ea is the active energy of the adhesive flow of slag, which corresponds to the potential energy barrier that needs to be overcome the effective movement of microstructure mass in the melt.

Mold fluxes was an aluminum silicate system, the size of the combined anion cluster was much larger than that of the metal cation, it was discussed before the larger the size of the ion cluster, the greater the resistance of slag [47], therefore, the activation energy of mold fluxes can characterize the changing trend of the complex anion group size in molten slag during cooling. When the activation energy of slag was greater, the more obvious trend of its network structure polymerization into complex structures was seen while temperature was decreased, and it showed that the viscosity increased faster as the temperature decreased from macroscopical view, which is detrimental to lubrication performance.

Depending on the viscosity-temperature curve, the activation energy values of samples were obtained in Table 4. It can be seen that, when BaO replaced CaO under different alkaline conditions, the viscous activity of fluorine-free mold fluxes showed a decreasing trend overall, explaining that as the temperature was decreased, the tendency of slag to converge into complex network structural units was also decreasing. It was stated that the replacement of CaO by BaO could improve the lubrication capacity of the slag during cooling process.

thumbnail Fig. 7

Viscosity-temperature curves of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

Table 4

Activation energy of CaO-SiO2-B2O3-BaO based mold fluxes.

4 Conclusion

To study the effect of BaO on the structure and fluid behavior of fluorine-free CaO-SiO2-B2O3-BaO mold fluxes, various techniques such as MD simulation, rotary viscometer, XRD and FTIR spectroscopy were exploited. The conclusions are summarized as follows:

  • The FTIR results matched well with the MD simulation results that with the addition of BaO contents in CaO-SiO2-B2O3 based melts, more cations were provided to balance the negative charge of [BO4]5– tetrahedrons, leading to the structures of Si-O and B-O were more aggregated and the adjacent structural units were more closely connected, which made the structure complex, so the viscosity of mold fluxes at high temperature in the basicity range 1.15–1.25 was intensify.

  • Depending on the viscosity-temperature curve, when BaO replaced CaO under distinctive basic conditions, the viscous activity of fluorine-free protective slag was decreasing generally, showing that as the temperature was decreased, the tendency of slag to converge into complex network structural units was also decreasing. It was stated that the replacement of CaO by BaO could improve the lubrication capacity of the slag during cooling process.

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgements

The authors would like to deeply appreciate the fund support from the Key projects of National Natural Science Foundation of China (U1760202) and the National Natural Science Foundation of China (51804004).

References

  1. K.C. Mills, A.B. Fox, Z. Li, Ironmak. Steelmak. 32, 26–34 (2005) [CrossRef] [Google Scholar]
  2. L.J. Zhou, W.L. Wang, F.J. Ma et al., Metall. Mater. Trans. B, 43, 354 (2012) [CrossRef] [Google Scholar]
  3. W.L. Wang, A.W. Cramb, ISIJ Int. 45, 1864–1870 (2005) [CrossRef] [Google Scholar]
  4. K.C. Mills, ISIJ Int. 56, 1 (2016) [CrossRef] [Google Scholar]
  5. Z.T. Zhang, G.H. Wen, Y.Y. Zhang, Int. J. Miner. 18, 150–158 (2011) [CrossRef] [Google Scholar]
  6. Z. Zhao, J. Zhao, B. Qu et al., PLoS ONE. 16, 1–11 (2021) [Google Scholar]
  7. L.J. Zhou, W.L. Wang, B. Lu et al., Metal Mater. Int. 21, 126 (2015) [CrossRef] [Google Scholar]
  8. W.L. Wang, H. Shao, L. Zhou et al., Cer. Inter. 46, 26880–26887 (2020) [CrossRef] [Google Scholar]
  9. B. Liu, K. Zhuang, D. Li et al., Comp. Part B: Eng. 200, 108311 (2020) [CrossRef] [Google Scholar]
  10. B. Lu, W. Wang, J. Li et al., Metall. Mater. Trans. B 44, 365 (2013) [CrossRef] [Google Scholar]
  11. H. Kim, I. Sohn, ISIJ Int. 51, 1–8 (2011) [CrossRef] [Google Scholar]
  12. J. Yang, J.Q. Zhang, O. Ostrovski et al., Metall. Mater. Trans. B 50, 291–303 (2019) [CrossRef] [MathSciNet] [Google Scholar]
  13. S. Sadaf, T. Wu, L. Zhong et al., Steel Res. Inter. 2000, 531 (2020) [Google Scholar]
  14. S. Sadaf, T. Wu, L. Zhong et al., Metals 10, 1240 (2020) [CrossRef] [Google Scholar]
  15. G.R. Li, Iron & Steel Res. Int. 10, 6 (2003) [Google Scholar]
  16. B.X. Lu, W.L. Wang, Metall. Mater. Trans. B 46, 852 (2015) [CrossRef] [Google Scholar]
  17. Z. Wang, I. Sohn, J. Am. Ceram. Soc. 101, 4285 (2018) [CrossRef] [Google Scholar]
  18. D. Xiao, W. Wang, B. Lu, The Min. Met. Mat. Soc. Acta 46, 873–881 (2015) [Google Scholar]
  19. E. Gao, W. Wang, L. Zhang, J. Non-Cryst. Solids 473, 79 (2017) [CrossRef] [Google Scholar]
  20. Y.S. Lee, J.R. Kim, S.H. Yi, et al., 7th International Conference on Molten Slags Fluxes and Salts 225, 225–230 (2004) [Google Scholar]
  21. T. Wu, PhD thesis Chongqing Uni., 2017 [Google Scholar]
  22. L.G. Back, S. Ali, S. Karlsson, Int. J. Appl. Glass Sci. 10, 349 (2019) [CrossRef] [Google Scholar]
  23. K. Zheng, Z.T. Zhang, F.H. Yang et al., ISIJ Int. 52, 342–349 (2012) [CrossRef] [Google Scholar]
  24. Q. Yuelin, L. Hao, Y. Yanhua, Metall. Res. Technol. 115, 113 (2018) [CrossRef] [EDP Sciences] [Google Scholar]
  25. L.V. Woodcock, C.A. Angell, P. Cheeseman, J. Chem. Phys. 65, 1564 (1976) [Google Scholar]
  26. B.P. Feuston, S.H. Garofalinim, J. Chem. Phys. 89, 5818 (1988) [CrossRef] [Google Scholar]
  27. K.J. Shimoda, K. Saito, ISIJ Int. 47, 1275 (2007) [CrossRef] [Google Scholar]
  28. K. Hirao, K. Kawamura, Tokyo 52, 52–54 (1994) [Google Scholar]
  29. P. Ganster, M. Benoit, W. Kob et al., J. Chem. Phys. 120, 10172 (2004) [CrossRef] [PubMed] [Google Scholar]
  30. V. Stahleisen, Verein Deutscher Eisenhüttenleute (R.F.A) Slag Atlas 2nd Edition, Verlag Stahleisen mbH, 119 (1995) [Google Scholar]
  31. K.C. Mills, B.J. Keene, Int. Mater. Rev. 32, 1 (1987) [Google Scholar]
  32. T. Wu, Q. Wang, S. He et al., Steel Res. Int. 83, 1194 (2012) [CrossRef] [Google Scholar]
  33. L. Zhang, W.L. Wang, S. Xie et al., J. Non-Cryst. Solids. 460, 113 (2017) [CrossRef] [Google Scholar]
  34. X. Qi, G.H. Wen, P. Tang, J. Iron Steel Res. Int. 17, 6 (2010) [CrossRef] [Google Scholar]
  35. J.H. Park, D.J. Min, H.S. Song, ISIJ Int. 42, 344 (2002) [CrossRef] [Google Scholar]
  36. H. Kim, H. Matsuura, F. Tsukihashi et al., Metall. Mater. Trans. B 44, 5 (2013) [CrossRef] [Google Scholar]
  37. H. Kim. W.H. Kim, I.D.J. Min, Steel Res. Int. 81, 261 (2010) [CrossRef] [Google Scholar]
  38. B. Li, X. Geng, Z. Jiang et al., Metals 165, 11 (2021) [Google Scholar]
  39. R.N. Mead, G. Mountjoy, J. Phys. Chem. B. 110, 14273 (2006) [CrossRef] [PubMed] [Google Scholar]
  40. D.R. Neuville, L. Cormier, V. Montouillout et al., J. Non-Cryst. Solids 353, 180 (2007) [CrossRef] [Google Scholar]
  41. E.I. Kamitsos, M.A. Karakassides, G.D. Chryssikos, J. Phys. Chem. 91, 1067 (1987) [CrossRef] [Google Scholar]
  42. H. Kim, H. Matsuura, F. Tsukihashi et al., Metall. Mater. Trans. B 44, 5–12 (2013) [CrossRef] [Google Scholar]
  43. G. Padmaja, P. Kistaiah, J. Phys. Chem. A 113, 2397 (2009) [CrossRef] [PubMed] [Google Scholar]
  44. Y.Q. Sun, J.L. Liao, K. Zheng et al., JOM. 66, 2168 (2014) [CrossRef] [Google Scholar]
  45. B.O. Mysen, J.D. Frantz, Am Mineral. 78, 699 (1993) [Google Scholar]
  46. I. Sohn, W.L. Wang, H. Matsuura et al., ISIJ Int. 52, 158 (2012) [CrossRef] [Google Scholar]
  47. K. Zheng, Z.T. Zhang, L.L. Liu, Metal. Mater. Trans. B. 45, 1389 (2014) [CrossRef] [Google Scholar]

Cite this article as: Shama Sadaf, Jie Lei, Hai-xiang Zhuang, Ting Wu, Hai-chuan Wang, Effective mechanism of BaO on the structure and fluid behavior of CaO-SiO2-B2O3-based melts, Metall. Res. Technol. 119, 208 (2022)

All Tables

Table 1

BMH potential parameters of atomic pairs in CaO-SiO2-B2O3-BaO melts.

Table 2

Composition content, atomic numbers, density and box length of CaO-SiO2-B2O3-BaO system at 1300 °C (wt%).

Table 3

Composition content of fluorine-free mold fluxes (wt%).

Table 4

Activation energy of CaO-SiO2-B2O3-BaO based mold fluxes.

All Figures

thumbnail Fig. 1

(a) Radial distribution function, and (b) average coordination number function of different atom pairs in sample B1-1.

In the text
thumbnail Fig. 2

Effect of BaO content on oxygen distribution in CaO-SiO2-B2O3-BaO system.

In the text
thumbnail Fig. 3

Effect of BaO content on structure unit Qi for Si and B in CaO-SiO2-B2O3-BaO system.

In the text
thumbnail Fig. 4

XRD results of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

In the text
thumbnail Fig. 5

FTIR spectra of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

In the text
thumbnail Fig. 6

Effect of BaO content on viscosity at 1300 °C of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

In the text
thumbnail Fig. 7

Viscosity-temperature curves of CaO-SiO2-B2O3-BaO-based mold fluxes at basicity 1.15 and 1.25.

In the text

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