Synthesis Of β-SiC Research Articles

Rapid and cost-effective fabrication of SiC from Si scrap through flash sintering

A rapid, cost-effective and eco-friendly approach for fabricating SiC using Si particles derived from Si scrap is highly recommended from both economic and environmental standpoints. Herein, we demonstrate the fabrication of β-SiC effectively in argon atmosphere at 1500°C by utilizing combustion synthesis followed by flash sintering in a single-step experiment for the first time. Synthesis of β-SiC was relied on exothermic reaction between Si and C elements present in the powder compact whereas densification was accomplished eventually through flash sintering. In addition, the effects of different flash sintering conditions on the properties of β-SiC are examined with and without Y2O3 sintering additive. A high relative density of 85% was realized when a current density of 60 mA/mm2 was applied for 60 min with Y2O3 addition. This novel one-step fabrication approach has the potential to reduce production cost of β-SiC significantly and has both commercial and environmental advantages.

Synthesis of α-SiC from tetramethylsilane by chemical vapor deposition at high temperature

Tetramethylsilane (TMS) is a common liquid-phase precursor that is used in the synthesis of β-SiC by chemical vapor deposition (CVD). At temperatures above 1500 °C, however, it has been shown that C is also formed together with SiC. In this study, based on thermodynamic modeling, we report on the successful synthesis of single-phase SiC with no evidence of the inclusion of C from TMS through CVD at temperatures over 1900 °C. X-ray diffraction data showed that α-SiC phases are formed at temperatures over 2000 °C. On the basis of these results, TMS can be used as a precursor for α-SiC synthesis.

Effect of Temperature and Carbon Contents on the Synthesis of β-SiC from Silicon Sludge by Direct Carbonization Method

β-SiC powder was synthesized using silicon sludge from photovoltaic silicon-wafer production by varying heat treatment temperature and carbon contents. The synthesized β-SiC powder and silicon sludge was analyzed by XRD, SEM, FT-IR and Particle size analysis. It is known that the conversion of SiC from the mixture of Silicon and Carbon is mainly affected by the mole ratio of C/Si and heat treatment temperature. In this study, the influence of reaction temperature and carbon contents on the synthesis of β-SiC from silicon sludge was examined.

Mechanism of Silicon/Carbon Reaction for β-SiC Bonded SiC Materials

Based on industrial silicon and carbon black as starting materials,β-SiC bonded SiC materials were prepared. The microstructure of such material and the silicon/carbon reaction were analyzed and investigated by XRD, SEM and other tools. The results indicate that the synthesis of β-SiC at 1400°C can be achieved through gas-phase mass transfer, liquid dissolution as well as in-situ reaction. While gas-phase mass transfer is the dominant reaction during the sintering of the material, in which β-SiC exists mainly as nanowhisker. The formation of β-SiC nanowires is believed to be the mechanism of reaction sintering.

Synthesis of β-SiC in the intermediate layer of corundum coatings based on a sol-gel binder for protecting graphite objects from oxidation

A coating is developed for protecting graphite from oxidation at 2023 – 2223 K. The efficiency of the protective action of a corundum coating based on a sol-gel binder increases due to creating a dense intermediate layer between the graphite substrate and the coating as a result of its self-reinforcement with fibers of mullite crystals and β-SiC nanoparticles. Components of a modifier and sol-gel binder, but not carbon of the graphite substrate, provide synthesis of β-SiC.

Synthesis of β-SiC by the Reaction of Gaseous SiO with Activated Carbon

Synthesis of β-SiC by the Reaction of Gaseous SiO with Activated Carbon

Synthesis of β-SiC and α-Si3N4 whiskers by the sol-gel process

A study is reported on a synthesis of α-Si3N4 whiskers from a modified ethyl silicate binder. It is noted that crystal growth induces thermal stresses. it is confirmed that such crystals are formed by a dislocation diffusion mechanism.

Low-temperature synthesis of SiC in heat-treatment of gels of hydrolyzed ethyl silicate

The problem of low-temperature synthesis of β-SiC in heat treatment of gels of hydrolyzed ethyl silicate is considered. Data obtained in DTA, IR, Raman spectroscopy, and EPR physicochemical investigations of the process of gel transformation in heat treatment in air are presented. A mechanism of the organization of the carbon system in a gel and possible ways of synthesizing SiC at low temperatures are suggested. Synthesis of SiC in heat treatment of gels of ethyl silicate at a rate exceeding 10 K/min is established by the x-ray method beginning with 773 K.

Combustion for the Synthesis of β-SiC and Diamond/SiC Composite

AbstractCubic β-SiC was processed under conditions of self-propagating high-temperature synthesis, based on the exothermic reaction between elemental Si and C powders. The set up for the synthesis of SiC using a mixture of Si and C is described. X-Ray and Raman spectroscopy studies were performed to characterize the quality of the β-SiC produced using the new set up. Scanning Electron Microscopy and Transmission Electron Microscopy studies were also carried out to study the mechanism of the formation of β-SiC from the elemental powders. The density of the compact and grain size of the graphite was found to be critical in the formation of the SiC. Diamond seeds were also implanted on the SiC pellet while compaction and this implanted diamond provided the necessary seed for the growth of a thick diamond film. The adhesion of the film is good because of its growth from the implanted diamond. Diamond films were grown on SiC using HFCVD. The quality and the adhesion of the diamond films on SiC were studied using SEM.