scholarly journals Ultrafast carbothermal reduction of silica to silicon using a CO2 laser beam

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Seok-Ho Maeng ◽  
Hakju Lee ◽  
Min Soo Park ◽  
Suhyun Park ◽  
Jaeki Jeong ◽  
...  
Keyword(s):  
Carbon Black ◽  
Laser Beam ◽  
Carbothermal Reduction ◽  
Gas Flow ◽  
Crystalline Silicon ◽  
Reduction Process ◽  
Reaction Chamber ◽  
Raman Shift ◽  
Influence Of Process Parameters ◽  
Laser Beam Intensity

AbstractWe report the extraction of silicon via a carbothermal reduction process using a CO2 laser beam as a heat source. The surface of a mixture of silica and carbon black powder became brown after laser beam irradiation for a few tens of seconds, and clear peaks of crystalline silicon were observed by Raman shift measurements, confirming the successful carbothermal reduction of silica. The influence of process parameters, including the laser beam intensity, radiation time, nitrogen gas flow in a reaction chamber, and the molar ratios of silica/carbon black of the mixture, on the carbothermal reduction process is explained in detail.

An Experimental Study on Laser Annealing of Thin Silicon Layers

1988 ◽  
Vol 110 (2) ◽  
pp. 416-423 ◽  
Author(s):  
C. P. Grigoropoulos ◽  
R. H. Buckholz ◽  
G. A. Domoto
Keyword(s):  
Laser Beam ◽  
Laser Annealing ◽  
Crystalline Silicon ◽  
Silicon Layer ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Beam Power ◽  
Silicon Phase ◽  
Laser Beam Intensity ◽  
Thin Silicon

A laser annealing technique directed toward producing single crystalline silicon on substrates is studied. In this paper the laser-induced melting of thin silicon films is studied experimentally. Direct heating of thin silicon layers on substrates is shown to produce a variety of different silicon melting patterns. A systematic study of these phase change phenomena has been performed. The important parameters are: (1) the laser beam power, (2) the laser beam intensity distribution, and (3) the speed of the translating silicon layer. Unstable silicon phase boundaries break up to form regions where solid and melt silicon coexist. Complicated silicon phase boundary patterns are shown. The experimental results showed the occurrence of organized patterns of alternating solid and liquid silicon stripes for two-dimensional heating distributions. Finally, temperature fields for the experimental operating conditions are calculated using an enthalpy model.

scholarly journals Thermodynamic analysis of interaction of components in the SIO2-C system: improvement of technical silicon production technological process

2021 ◽  
Vol 22 (2) ◽  
pp. 345-352
Author(s):  
Inga Janelidze ◽  
Gigo Jandieri ◽  
Tamar Tsertsvadze
Keyword(s):  
Technological Process ◽  
Thermodynamic Analysis ◽  
Carbothermal Reduction ◽  
Crystalline Silicon ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Technical Solution ◽  
Chemical Furnace ◽  
Interaction Of Components ◽  
Degree Of Extraction

In order to identify ways to improve the technological process of smelting metallic (crystalline) silicon of technical purity, a thermodynamic analysis of the interaction of components in the SiO2-C system is carried out that reveals the main factor in obtaining high-quality technical silicon is the elimination of superposition of the silicon carbonization process that is possible by carrying out a two-stage carbothermal reduction reaction, in that firstly the incomplete reduction of silica (SiO2) by solid carbon (C) is provided, accompanied by the release of new reacting gas components - SiO and CO, the subsequent interaction of which leads to the formation of the target product - technical silicon that is suitable for the production of modern solar energy converters. It is determined that main condition for highly efficient reduction reactions is the fine fractionness (<1 mm) of the used quartzite ore with keeping of a rational temperature range for its carbothermal reduction (1688-2000 K). It has been shown experimentally that the optimal technical solution for the implementation of this reduction process is to performt melting in a special plasma-chemical furnace-reactor with one liquid-metal subconducting electrode, with a reverse vertical feed of the reaction gases released at the first stage. The degree of extraction of silicon was on average 95%, and the degree of its purity was 97.2%.

Synthesis of Al4SiC4-Al8SiC7 Composite Powders by Carbothermal Reduction Process

2011 ◽  
Vol 399-401 ◽  
pp. 813-816 ◽  
Author(s):  
Chao Yu ◽  
Wen Jie Yuan ◽  
Jun Li ◽  
Hong Xi Zhu ◽  
Cheng Ji Deng
Keyword(s):  
Carbon Black ◽  
Carbothermal Reduction ◽  
Carbothermic Reduction ◽  
Heating Temperature ◽  
Reduction Process ◽  
Composite Powders

Tabular structure of Al4SiC4-Al8SiC7composites was successfully synthesized using a mixture of calcined bauxite, SiC and carbon black by a carbothermal reduction process. The effects of the amount of SiC addition and the heating temperature on synthesis of Al4SiC4-Al8SiC7composites by carbothermic reduction were investigated. The results show that SiC amount played an important role in the content of the final products. With the increasing of heating temperature, the Al4SiC4content increased and Al8SiC7content decreased in the products, which indicated the formation and growth of Al4SiC4were promoted.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

Influence of Thermal Deformations in the Solid Laser Medium on the Emitted Radiation Parameters

2005 ◽  
Vol 219 (8) ◽  
pp. 823-827
Author(s):  
O Donţu ◽  
S Ganatsios ◽  
D Duminica
Keyword(s):  
Laser Beam ◽  
Radial Distribution ◽  
Thermal Deformation ◽  
Processing Parameters ◽  
Beam Intensity ◽  
Laser Medium ◽  
Laser Beam Intensity ◽  
Active Laser ◽  
Thermal Deformations ◽  
Active Laser Medium

The paper presents some remarks about the way in which the thermal deformation in the solid active laser medium influences the radial distribution of the emitted laser beam intensity, implicitly the processing parameters.

scholarly journals Titanium Carbide Nanocrystals Synthesized from a Metatitanic Acid-Sucrose Precursor via a Carbothermal Reduction

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hyunho Shin ◽  
Jun-Ho Eun
Keyword(s):  
Process Control ◽  
Titanium Carbide ◽  
Specific Surface ◽  
Surface Area ◽  
Pore Volume ◽  
Carbothermal Reduction ◽  
Crystal Size ◽  
Reduction Process ◽  
Specific Pore Volume ◽  
Metatitanic Acid

A TiC powder is synthesized from a micron-sized mesoporous metatitanic acid-sucrose precursor (precursor M) by a carbothermal reduction process. Control specimens are also prepared using a nanosized TiO2-sucrose precursor (precursor T) with a higher cost. When synthesized at 1500°C for 2 h in flowing Ar, the characteristics of the synthesized TiC from precursor M are similar to those of the counterpart from precursor T in terms of the crystal size (58.5 versus 57.4 nm), oxygen content (0.22 wt% versus 0.25 wt%), and representative sizes of mesopores: approximately 2.5 and 19.7–25.0 nm in both specimens. The most salient differences of the two specimens are found in the TiC from precursor M demonstrating (i) a higher crystallinity based on the distinctive doublet peaks in the high-two-theta XRD regime and (ii) a lower specific surface area (79.4 versus 94.8 m2/g) with a smaller specific pore volume (0.1 versus 0.2 cm3/g) than the counterpart from precursor T.

The SiNx films process research by plasma-enhanced chemical vapor deposition in crystalline silicon solar cells

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744101 ◽  
Author(s):  
Bitao Chen ◽  
Yingke Zhang ◽  
Qiuping Ouyang ◽  
Fei Chen ◽  
Xinghua Zhan ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Solar Cell ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Silicon Solar Cell ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Double Layers ◽  
Crystalline Silicon Solar Cell

SiNx thin film has been widely used in crystalline silicon solar cell production because of the good anti-reflection and passivation effect. We can effectively optimize the cells performance by plasma-enhanced chemical vapor deposition (PECVD) method to change deposition conditions such as temperature, gas flow ratio, etc. In this paper, we deposit a new layer of SiNx thin film on the basis of double-layers process. By changing the process parameters, the compactness of thin films is improved effectively. The NH3passivation technology is augmented in a creative way, which improves the minority carrier lifetime. In sight of this, a significant increase is generated in the photoelectric performance of crystalline silicon solar cell.

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