Time and Temperature Dependence of the Solubility of Carbon in Liquid Silicon Equilibrated with Silicon Carbide and Its Dependence on Boron Levels

Dalaker, Halvor; Tangstad, Merete

doi:10.2320/matertrans.m2009034

Cited by 18 publications

(20 citation statements)

References 11 publications

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“…At the working temperature of 1500°C, silicon is in the liquid state and in equilibrium with SiC. Furthermore, according to literature data, the maximum value of carbon solubility into liquid silicon at 1500°C is found equal to 170 ppm in mass as shown in Figure 1-b) [19][20][21][22][23]. From this very low value, the interaction between pure molten silicon and SiC can be considered a priori as negligible.…”

Section: Background On the Capillary Infiltration Of Silicon Into Pormentioning

confidence: 77%

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SiC/Si composites elaboration by capillary infiltration of molten silicon

Roger

Guesnet

Marchais

et al. 2018

Journal of Alloys and Compounds

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Infiltration of molten metal into ceramic performs without external pressure is a promising fabrication method for metal-matrix composites. Thus, this research is focused on the kinetic of capillary infiltration in the processing of Si/SiC composites. The calculation of the infiltration kinetics for a liquid in a porous material is possible by applying the modified-Washburn equation which involves the effective diameter of the pores. This equation implies a K value depending on the wetting angle, the density, the viscosity and the surface tension of the liquid at a given temperature. In this study, the main aim was to measure the K Si value of molten silicon infiltration into porous SiC at 1500°C. On this way, consolidated β-SiC powder compacts were prepared for infiltration experiments. The effects of the SiC particles presintering on the pore size were examined as they can affect molten silicon infiltration. So, the monitoring of the mass increase during hexadecane rise was used to determine the effective diameter of the pores. It was evidenced that an increase of 15.5% of the initial effective diameter occurs. Consequently, a corresponding correction has to be applied to the initial effective diameter of the siliconinfiltrated compacts. Infiltrations of pure molten silicon into SiC compacts were successfully carried out at 1500°C under high vacuum (5.10 -3 mbar) and the average value of K Si was found equal to (5.8±0.4)×10 -6 cm 5 .s.g -2 . The effect of molten silicon rise on the porosity was also considered.

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Section: Background On the Capillary Infiltration Of Silicon Into Pormentioning

confidence: 77%

“…Figure 1. Si-C system: a) calculated Si-C diagram [18,19] and b) solubility of carbon in molten silicon from literature [19][20][21][22][23]. The values from Grobner et al were calculated by using ThermoCalc software [18].…”

Section: Resultsmentioning

confidence: 99%

SiC/Si composites elaboration by capillary infiltration of molten silicon

Roger

Guesnet

Marchais

et al. 2018

Journal of Alloys and Compounds

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“…That is why they were examined at 1600 1C by Eremenko et al [29]. Some other authors also examined the solubility of carbon in molten silicon [3,[30][31][32][33]. It is clear that carbon is very slightly soluble in molten silicon at 1450 1C (less than 100 ppm in mass) but all the studies indicate a noticeable increase with temperature (Fig.…”

Section: Introductionmentioning

confidence: 96%

Examination of the interaction between liquid silicon and bulk silicon carbide

Roger

Marchais

Petitcorps

2015

Journal of Crystal Growth

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International audienceLittle information is available about the evolution of SiC in presence of molten silicon. In this context, two kinds of experiments relative to the interaction between SiC substrates and molten Si were performed between 1450 and 1600°C with: 1) dense α-SiC bars and 2) dense α-SiC pellets coated with a β-SiC layer deposited by CVD. The results obtained indicate that an important crystal growth occurs in any cases. Large and facetted SiC crystals have grown on the surface of the SiC substrates and on the whole surface of molten silicon. These crystals are formed by dissolution-growth mechanism of SiC substrates with kinetics depending on the temperature. Low thermal gradients within the samples and between the inner parts and/or the surface of the samples could noticeably promote the evolution of the system by generating a carbon flux. The interaction between molten silicon and SiC is of importance because it could have some effects on the physical and chemical properties of the materials. It is well known that large grains are deleterious for mechanical properties

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“…The carbon solubility in liquid silicon has been determined by different authors, but the values differ in one order of magnitude, as shown by Dalaker and Tangstad. [1] These authors claim that the spread in the solubility values is a result of uncontrolled sources of carbon and oxygen, such as the crucible wall. Therefore, Dalaker and Tangstad [1] carried out carefully controlled experiments and obtained the carbon solubility in liquid silicon as 65 ppmw at the melting point 1687 K (1414°C).…”

mentioning

confidence: 99%

“…[1] These authors claim that the spread in the solubility values is a result of uncontrolled sources of carbon and oxygen, such as the crucible wall. Therefore, Dalaker and Tangstad [1] carried out carefully controlled experiments and obtained the carbon solubility in liquid silicon as 65 ppmw at the melting point 1687 K (1414°C). Therefore, approximately 90 pct of carbon in MGSi is combined in SiC particles.…”

mentioning

confidence: 99%

Effects of Solidification Rate and Settling Time of SiC Particles on the Macrosegregation of Carbon in Silicon Ingots

Ribeiro

Neto

Martorano

2014

Metallurgical and Materials Transactions E

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The macrosegregation of carbon in silicon was studied aiming for silicon refining for photovoltaic applications. Experiments of directional solidification upward and of settling of SiC particles in the melt were carried out in a Bridgman furnace using electronic grade silicon intentionally contaminated with carbon. Mold pulling velocities in the range between 5 and 80 lm/s and settling time periods of 1 and 6 hours were adopted in the experiments. In the resulting cylindrical ingots, the macrosegregation of carbon along the axial direction was measured and their macro and microstructures revealed and examined. In all directional solidification experiments, the carbon concentration increases to the ingot top as result of an accumulation of SiC particles in this region. For the lower velocities (<40 lm/s), a larger particle accumulation and columnar grains aligned axially and pointing to the ingot top are seen, which is consistent with the pushing of SiC particles by a planar solid-liquid interface. For the settling experiments, the carbon concentration increases from the ingot top to the bottom as a result of the accumulation of SiC particles at the bottom. This accumulation is probably caused by the settling of SiC particles, but an increase in the settling time from 1 to 6 hours have no significant effect in the macrosegregation profile. Finally, in the conditions of the present experiments, the directional solidification of silicon at mold pulling velocities lower than 40 lm/s is more effective to remove carbon from silicon than the settling of SiC particles during times up to 6 hours.

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Time and Temperature Dependence of the Solubility of Carbon in Liquid Silicon Equilibrated with Silicon Carbide and Its Dependence on Boron Levels

Cited by 18 publications

References 11 publications

SiC/Si composites elaboration by capillary infiltration of molten silicon

SiC/Si composites elaboration by capillary infiltration of molten silicon

Examination of the interaction between liquid silicon and bulk silicon carbide

Effects of Solidification Rate and Settling Time of SiC Particles on the Macrosegregation of Carbon in Silicon Ingots

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